/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.regex.Pattern;
/**
* <p>Operations on {@link java.lang.String} that are
* {@code null} safe.</p>
*
* <ul>
* <li><b>IsEmpty/IsBlank</b>
* - checks if a String contains text</li>
* <li><b>Trim/Strip</b>
* - removes leading and trailing whitespace</li>
* <li><b>Equals</b>
* - compares two strings null-safe</li>
* <li><b>startsWith</b>
* - check if a String starts with a prefix null-safe</li>
* <li><b>endsWith</b>
* - check if a String ends with a suffix null-safe</li>
* <li><b>IndexOf/LastIndexOf/Contains</b>
* - null-safe index-of checks
* <li><b>IndexOfAny/LastIndexOfAny/IndexOfAnyBut/LastIndexOfAnyBut</b>
* - index-of any of a set of Strings</li>
* <li><b>ContainsOnly/ContainsNone/ContainsAny</b>
* - does String contains only/none/any of these characters</li>
* <li><b>Substring/Left/Right/Mid</b>
* - null-safe substring extractions</li>
* <li><b>SubstringBefore/SubstringAfter/SubstringBetween</b>
* - substring extraction relative to other strings</li>
* <li><b>Split/Join</b>
* - splits a String into an array of substrings and vice versa</li>
* <li><b>Remove/Delete</b>
* - removes part of a String</li>
* <li><b>Replace/Overlay</b>
* - Searches a String and replaces one String with another</li>
* <li><b>Chomp/Chop</b>
* - removes the last part of a String</li>
* <li><b>LeftPad/RightPad/Center/Repeat</b>
* - pads a String</li>
* <li><b>UpperCase/LowerCase/SwapCase/Capitalize/Uncapitalize</b>
* - changes the case of a String</li>
* <li><b>CountMatches</b>
* - counts the number of occurrences of one String in another</li>
* <li><b>IsAlpha/IsNumeric/IsWhitespace/IsAsciiPrintable</b>
* - checks the characters in a String</li>
* <li><b>DefaultString</b>
* - protects against a null input String</li>
* <li><b>Reverse/ReverseDelimited</b>
* - reverses a String</li>
* <li><b>Abbreviate</b>
* - abbreviates a string using ellipsis</li>
* <li><b>Difference</b>
* - compares Strings and reports on their differences</li>
* <li><b>LevenshteinDistance</b>
* - the number of changes needed to change one String into another</li>
* </ul>
*
* <p>The {@code StringUtils} class defines certain words related to
* String handling.</p>
*
* <ul>
* <li>null - {@code null}</li>
* <li>empty - a zero-length string ({@code ""})</li>
* <li>space - the space character ({@code ' '}, char 32)</li>
* <li>whitespace - the characters defined by {@link Character#isWhitespace(char)}</li>
* <li>trim - the characters <= 32 as in {@link String#trim()}</li>
* </ul>
*
* <p>{@code StringUtils} handles {@code null} input Strings quietly.
* That is to say that a {@code null} input will return {@code null}.
* Where a {@code boolean} or {@code int} is being returned
* details vary by method.</p>
*
* <p>A side effect of the {@code null} handling is that a
* {@code NullPointerException} should be considered a bug in
* {@code StringUtils}.</p>
*
* <p>Methods in this class give sample code to explain their operation.
* The symbol {@code *} is used to indicate any input including {@code null}.</p>
*
* <p>#ThreadSafe#</p>
* @see java.lang.String
* @since 1.0
* @version $Id: StringUtils.java 1153241 2011-08-02 18:49:52Z ggregory $
*/
//@Immutable
public class StringUtils {
// Performance testing notes (JDK 1.4, Jul03, scolebourne)
// Whitespace:
// Character.isWhitespace() is faster than WHITESPACE.indexOf()
// where WHITESPACE is a string of all whitespace characters
//
// Character access:
// String.charAt(n) versus toCharArray(), then array[n]
// String.charAt(n) is about 15% worse for a 10K string
// They are about equal for a length 50 string
// String.charAt(n) is about 4 times better for a length 3 string
// String.charAt(n) is best bet overall
//
// Append:
// String.concat about twice as fast as StringBuffer.append
// (not sure who tested this)
/**
* The empty String {@code ""}.
* @since 2.0
*/
public static final String EMPTY = "";
/**
* Represents a failed index search.
* @since 2.1
*/
public static final int INDEX_NOT_FOUND = -1;
/**
* <p>The maximum size to which the padding constant(s) can expand.</p>
*/
private static final int PAD_LIMIT = 8192;
/**
* A regex pattern for recognizing blocks of whitespace characters.
*/
private static final Pattern WHITESPACE_BLOCK = Pattern.compile("\\s+");
/**
* <p>{@code StringUtils} instances should NOT be constructed in
* standard programming. Instead, the class should be used as
* {@code StringUtils.trim(" foo ");}.</p>
*
* <p>This constructor is public to permit tools that require a JavaBean
* instance to operate.</p>
*/
public StringUtils() {
super();
}
// Empty checks
//-----------------------------------------------------------------------
/**
* <p>Checks if a CharSequence is empty ("") or null.</p>
*
* <pre>
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
* </pre>
*
* <p>NOTE: This method changed in Lang version 2.0.
* It no longer trims the CharSequence.
* That functionality is available in isBlank().</p>
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is empty or null
* @since 3.0 Changed signature from isEmpty(String) to isEmpty(CharSequence)
*/
public static boolean isEmpty(CharSequence cs) {
return cs == null || cs.length() == 0;
}
/**
* <p>Checks if a CharSequence is not empty ("") and not null.</p>
*
* <pre>
* StringUtils.isNotEmpty(null) = false
* StringUtils.isNotEmpty("") = false
* StringUtils.isNotEmpty(" ") = true
* StringUtils.isNotEmpty("bob") = true
* StringUtils.isNotEmpty(" bob ") = true
* </pre>
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is not empty and not null
* @since 3.0 Changed signature from isNotEmpty(String) to isNotEmpty(CharSequence)
*/
public static boolean isNotEmpty(CharSequence cs) {
return !StringUtils.isEmpty(cs);
}
/**
* <p>Checks if a CharSequence is whitespace, empty ("") or null.</p>
*
* <pre>
* StringUtils.isBlank(null) = true
* StringUtils.isBlank("") = true
* StringUtils.isBlank(" ") = true
* StringUtils.isBlank("bob") = false
* StringUtils.isBlank(" bob ") = false
* </pre>
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is null, empty or whitespace
* @since 2.0
* @since 3.0 Changed signature from isBlank(String) to isBlank(CharSequence)
*/
public static boolean isBlank(CharSequence cs) {
int strLen;
if (cs == null || (strLen = cs.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if ((Character.isWhitespace(cs.charAt(i)) == false)) {
return false;
}
}
return true;
}
/**
* <p>Checks if a CharSequence is not empty (""), not null and not whitespace only.</p>
*
* <pre>
* StringUtils.isNotBlank(null) = false
* StringUtils.isNotBlank("") = false
* StringUtils.isNotBlank(" ") = false
* StringUtils.isNotBlank("bob") = true
* StringUtils.isNotBlank(" bob ") = true
* </pre>
*
* @param cs the CharSequence to check, may be null
* @return {@code true} if the CharSequence is
* not empty and not null and not whitespace
* @since 2.0
* @since 3.0 Changed signature from isNotBlank(String) to isNotBlank(CharSequence)
*/
public static boolean isNotBlank(CharSequence cs) {
return !StringUtils.isBlank(cs);
}
// Trim
//-----------------------------------------------------------------------
/**
* <p>Removes control characters (char <= 32) from both
* ends of this String, handling {@code null} by returning
* {@code null}.</p>
*
* <p>The String is trimmed using {@link String#trim()}.
* Trim removes start and end characters <= 32.
* To strip whitespace use {@link #strip(String)}.</p>
*
* <p>To trim your choice of characters, use the
* {@link #strip(String, String)} methods.</p>
*
* <pre>
* StringUtils.trim(null) = null
* StringUtils.trim("") = ""
* StringUtils.trim(" ") = ""
* StringUtils.trim("abc") = "abc"
* StringUtils.trim(" abc ") = "abc"
* </pre>
*
* @param str the String to be trimmed, may be null
* @return the trimmed string, {@code null} if null String input
*/
public static String trim(String str) {
return str == null ? null : str.trim();
}
/**
* <p>Removes control characters (char <= 32) from both
* ends of this String returning {@code null} if the String is
* empty ("") after the trim or if it is {@code null}.
*
* <p>The String is trimmed using {@link String#trim()}.
* Trim removes start and end characters <= 32.
* To strip whitespace use {@link #stripToNull(String)}.</p>
*
* <pre>
* StringUtils.trimToNull(null) = null
* StringUtils.trimToNull("") = null
* StringUtils.trimToNull(" ") = null
* StringUtils.trimToNull("abc") = "abc"
* StringUtils.trimToNull(" abc ") = "abc"
* </pre>
*
* @param str the String to be trimmed, may be null
* @return the trimmed String,
* {@code null} if only chars <= 32, empty or null String input
* @since 2.0
*/
public static String trimToNull(String str) {
String ts = trim(str);
return isEmpty(ts) ? null : ts;
}
/**
* <p>Removes control characters (char <= 32) from both
* ends of this String returning an empty String ("") if the String
* is empty ("") after the trim or if it is {@code null}.
*
* <p>The String is trimmed using {@link String#trim()}.
* Trim removes start and end characters <= 32.
* To strip whitespace use {@link #stripToEmpty(String)}.</p>
*
* <pre>
* StringUtils.trimToEmpty(null) = ""
* StringUtils.trimToEmpty("") = ""
* StringUtils.trimToEmpty(" ") = ""
* StringUtils.trimToEmpty("abc") = "abc"
* StringUtils.trimToEmpty(" abc ") = "abc"
* </pre>
*
* @param str the String to be trimmed, may be null
* @return the trimmed String, or an empty String if {@code null} input
* @since 2.0
*/
public static String trimToEmpty(String str) {
return str == null ? EMPTY : str.trim();
}
// Stripping
//-----------------------------------------------------------------------
/**
* <p>Strips whitespace from the start and end of a String.</p>
*
* <p>This is similar to {@link #trim(String)} but removes whitespace.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.strip(null) = null
* StringUtils.strip("") = ""
* StringUtils.strip(" ") = ""
* StringUtils.strip("abc") = "abc"
* StringUtils.strip(" abc") = "abc"
* StringUtils.strip("abc ") = "abc"
* StringUtils.strip(" abc ") = "abc"
* StringUtils.strip(" ab c ") = "ab c"
* </pre>
*
* @param str the String to remove whitespace from, may be null
* @return the stripped String, {@code null} if null String input
*/
public static String strip(String str) {
return strip(str, null);
}
/**
* <p>Strips whitespace from the start and end of a String returning
* {@code null} if the String is empty ("") after the strip.</p>
*
* <p>This is similar to {@link #trimToNull(String)} but removes whitespace.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripToNull(null) = null
* StringUtils.stripToNull("") = null
* StringUtils.stripToNull(" ") = null
* StringUtils.stripToNull("abc") = "abc"
* StringUtils.stripToNull(" abc") = "abc"
* StringUtils.stripToNull("abc ") = "abc"
* StringUtils.stripToNull(" abc ") = "abc"
* StringUtils.stripToNull(" ab c ") = "ab c"
* </pre>
*
* @param str the String to be stripped, may be null
* @return the stripped String,
* {@code null} if whitespace, empty or null String input
* @since 2.0
*/
public static String stripToNull(String str) {
if (str == null) {
return null;
}
str = strip(str, null);
return str.length() == 0 ? null : str;
}
/**
* <p>Strips whitespace from the start and end of a String returning
* an empty String if {@code null} input.</p>
*
* <p>This is similar to {@link #trimToEmpty(String)} but removes whitespace.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripToEmpty(null) = ""
* StringUtils.stripToEmpty("") = ""
* StringUtils.stripToEmpty(" ") = ""
* StringUtils.stripToEmpty("abc") = "abc"
* StringUtils.stripToEmpty(" abc") = "abc"
* StringUtils.stripToEmpty("abc ") = "abc"
* StringUtils.stripToEmpty(" abc ") = "abc"
* StringUtils.stripToEmpty(" ab c ") = "ab c"
* </pre>
*
* @param str the String to be stripped, may be null
* @return the trimmed String, or an empty String if {@code null} input
* @since 2.0
*/
public static String stripToEmpty(String str) {
return str == null ? EMPTY : strip(str, null);
}
/**
* <p>Strips any of a set of characters from the start and end of a String.
* This is similar to {@link String#trim()} but allows the characters
* to be stripped to be controlled.</p>
*
* <p>A {@code null} input String returns {@code null}.
* An empty string ("") input returns the empty string.</p>
*
* <p>If the stripChars String is {@code null}, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
* Alternatively use {@link #strip(String)}.</p>
*
* <pre>
* StringUtils.strip(null, *) = null
* StringUtils.strip("", *) = ""
* StringUtils.strip("abc", null) = "abc"
* StringUtils.strip(" abc", null) = "abc"
* StringUtils.strip("abc ", null) = "abc"
* StringUtils.strip(" abc ", null) = "abc"
* StringUtils.strip(" abcyx", "xyz") = " abc"
* </pre>
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, {@code null} if null String input
*/
public static String strip(String str, String stripChars) {
if (isEmpty(str)) {
return str;
}
str = stripStart(str, stripChars);
return stripEnd(str, stripChars);
}
/**
* <p>Strips any of a set of characters from the start of a String.</p>
*
* <p>A {@code null} input String returns {@code null}.
* An empty string ("") input returns the empty string.</p>
*
* <p>If the stripChars String is {@code null}, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripStart(null, *) = null
* StringUtils.stripStart("", *) = ""
* StringUtils.stripStart("abc", "") = "abc"
* StringUtils.stripStart("abc", null) = "abc"
* StringUtils.stripStart(" abc", null) = "abc"
* StringUtils.stripStart("abc ", null) = "abc "
* StringUtils.stripStart(" abc ", null) = "abc "
* StringUtils.stripStart("yxabc ", "xyz") = "abc "
* </pre>
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, {@code null} if null String input
*/
public static String stripStart(String str, String stripChars) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return str;
}
int start = 0;
if (stripChars == null) {
while ((start != strLen) && Character.isWhitespace(str.charAt(start))) {
start++;
}
} else if (stripChars.length() == 0) {
return str;
} else {
while ((start != strLen) && (stripChars.indexOf(str.charAt(start)) != INDEX_NOT_FOUND)) {
start++;
}
}
return str.substring(start);
}
/**
* <p>Strips any of a set of characters from the end of a String.</p>
*
* <p>A {@code null} input String returns {@code null}.
* An empty string ("") input returns the empty string.</p>
*
* <p>If the stripChars String is {@code null}, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripEnd(null, *) = null
* StringUtils.stripEnd("", *) = ""
* StringUtils.stripEnd("abc", "") = "abc"
* StringUtils.stripEnd("abc", null) = "abc"
* StringUtils.stripEnd(" abc", null) = " abc"
* StringUtils.stripEnd("abc ", null) = "abc"
* StringUtils.stripEnd(" abc ", null) = " abc"
* StringUtils.stripEnd(" abcyx", "xyz") = " abc"
* StringUtils.stripEnd("120.00", ".0") = "12"
* </pre>
*
* @param str the String to remove characters from, may be null
* @param stripChars the set of characters to remove, null treated as whitespace
* @return the stripped String, {@code null} if null String input
*/
public static String stripEnd(String str, String stripChars) {
int end;
if (str == null || (end = str.length()) == 0) {
return str;
}
if (stripChars == null) {
while ((end != 0) && Character.isWhitespace(str.charAt(end - 1))) {
end--;
}
} else if (stripChars.length() == 0) {
return str;
} else {
while ((end != 0) && (stripChars.indexOf(str.charAt(end - 1)) != INDEX_NOT_FOUND)) {
end--;
}
}
return str.substring(0, end);
}
// StripAll
//-----------------------------------------------------------------------
/**
* <p>Strips whitespace from the start and end of every String in an array.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>A new array is returned each time, except for length zero.
* A {@code null} array will return {@code null}.
* An empty array will return itself.
* A {@code null} array entry will be ignored.</p>
*
* <pre>
* StringUtils.stripAll(null) = null
* StringUtils.stripAll([]) = []
* StringUtils.stripAll(["abc", " abc"]) = ["abc", "abc"]
* StringUtils.stripAll(["abc ", null]) = ["abc", null]
* </pre>
*
* @param strs the array to remove whitespace from, may be null
* @return the stripped Strings, {@code null} if null array input
*/
public static String[] stripAll(String... strs) {
return stripAll(strs, null);
}
/**
* <p>Strips any of a set of characters from the start and end of every
* String in an array.</p>
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>A new array is returned each time, except for length zero.
* A {@code null} array will return {@code null}.
* An empty array will return itself.
* A {@code null} array entry will be ignored.
* A {@code null} stripChars will strip whitespace as defined by
* {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.stripAll(null, *) = null
* StringUtils.stripAll([], *) = []
* StringUtils.stripAll(["abc", " abc"], null) = ["abc", "abc"]
* StringUtils.stripAll(["abc ", null], null) = ["abc", null]
* StringUtils.stripAll(["abc ", null], "yz") = ["abc ", null]
* StringUtils.stripAll(["yabcz", null], "yz") = ["abc", null]
* </pre>
*
* @param strs the array to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped Strings, {@code null} if null array input
*/
public static String[] stripAll(String[] strs, String stripChars) {
int strsLen;
if (strs == null || (strsLen = strs.length) == 0) {
return strs;
}
String[] newArr = new String[strsLen];
for (int i = 0; i < strsLen; i++) {
newArr[i] = strip(strs[i], stripChars);
}
return newArr;
}
/**
* <p>Removes diacritics (~= accents) from a string. The case will not be altered.</p>
* <p>For instance, 'à' will be replaced by 'a'.</p>
* <p>Note that ligatures will be left as is.</p>
*
* <p>This method will use the first available implementation of:
* Java 6's {@link java.text.Normalizer}, Java 1.3–1.5's {@code sun.text.Normalizer}</p>
*
* <pre>
* StringUtils.stripAccents(null) = null
* StringUtils.stripAccents("") = ""
* StringUtils.stripAccents("control") = "control"
* StringUtils.stripAccents("éclair") = "eclair"
* </pre>
*
* @param input String to be stripped
* @return input text with diacritics removed
*
* @since 3.0
*/
// See also Lucene's ASCIIFoldingFilter (Lucene 2.9) that replaces accented characters by their unaccented equivalent (and uncommitted bug fix: https://issues.apache.org/jira/browse/LUCENE-1343?focusedCommentId=12858907&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#action_12858907).
public static String stripAccents(String input) {
if(input == null) {
return null;
}
try {
String result = null;
if (java6Available) {
result = removeAccentsJava6(input);
} else if (sunAvailable) {
result = removeAccentsSUN(input);
} else {
throw new UnsupportedOperationException(
"The stripAccents(CharSequence) method requires at least Java 1.6 or a Sun JVM");
}
// Note that none of the above methods correctly remove ligatures...
return result;
} catch(IllegalArgumentException iae) {
throw new RuntimeException("IllegalArgumentException occurred", iae);
} catch(IllegalAccessException iae) {
throw new RuntimeException("IllegalAccessException occurred", iae);
} catch(InvocationTargetException ite) {
throw new RuntimeException("InvocationTargetException occurred", ite);
} catch(SecurityException se) {
throw new RuntimeException("SecurityException occurred", se);
}
}
/**
* Use {@code java.text.Normalizer#normalize(CharSequence, Normalizer.Form)}
* (but be careful, this class exists in Java 1.3, with an entirely different meaning!)
*
* @param text the text to be processed
* @return the processed string
* @throws IllegalAccessException may be thrown by a reflection call
* @throws InvocationTargetException if a reflection call throws an exception
* @throws IllegalStateException if the {@code Normalizer} class is not available
*/
private static String removeAccentsJava6(CharSequence text)
throws IllegalAccessException, InvocationTargetException {
/*
String decomposed = java.text.Normalizer.normalize(CharSequence, Normalizer.Form.NFD);
return java6Pattern.matcher(decomposed).replaceAll("");//$NON-NLS-1$
*/
if (!java6Available || java6NormalizerFormNFD == null) {
throw new IllegalStateException("java.text.Normalizer is not available");
}
String result;
result = (String) java6NormalizeMethod.invoke(null, new Object[] {text, java6NormalizerFormNFD});
result = java6Pattern.matcher(result).replaceAll("");//$NON-NLS-1$
return result;
}
/**
* Use {@code sun.text.Normalizer#decompose(String, boolean, int)}
*
* @param text the text to be processed
* @return the processed string
* @throws IllegalAccessException may be thrown by a reflection call
* @throws InvocationTargetException if a reflection call throws an exception
* @throws IllegalStateException if the {@code Normalizer} class is not available
*/
private static String removeAccentsSUN(CharSequence text)
throws IllegalAccessException, InvocationTargetException {
/*
String decomposed = sun.text.Normalizer.decompose(text, false, 0);
return sunPattern.matcher(decomposed).replaceAll("");//$NON-NLS-1$
*/
if (! sunAvailable) {
throw new IllegalStateException("sun.text.Normalizer is not available");
}
String result;
result = (String) sunDecomposeMethod.invoke(null, new Object[] {text, Boolean.FALSE, Integer.valueOf(0)});
result = sunPattern.matcher(result).replaceAll("");//$NON-NLS-1$
return result;
}
// SUN internal, Java 1.3 -> Java 5
private static boolean sunAvailable = false;
private static Method sunDecomposeMethod = null;
private static final Pattern sunPattern = Pattern.compile("\\p{InCombiningDiacriticalMarks}+");//$NON-NLS-1$
// Java 6+
private static boolean java6Available = false;
private static Method java6NormalizeMethod = null;
private static Object java6NormalizerFormNFD = null;
private static final Pattern java6Pattern = sunPattern;
static {
try {
// java.text.Normalizer.normalize(CharSequence, Normalizer.Form.NFD);
// Be careful not to get Java 1.3 java.text.Normalizer!
Class<?> normalizerFormClass = Thread.currentThread().getContextClassLoader()
.loadClass("java.text.Normalizer$Form");//$NON-NLS-1$
java6NormalizerFormNFD = normalizerFormClass.getField("NFD").get(null);//$NON-NLS-1$
Class<?> normalizerClass = Thread.currentThread().getContextClassLoader()
.loadClass("java.text.Normalizer");//$NON-NLS-1$
java6NormalizeMethod = normalizerClass.getMethod("normalize",
new Class[] {CharSequence.class, normalizerFormClass});//$NON-NLS-1$
java6Available = true;
} catch (ClassNotFoundException e) {
java6Available = false;
} catch (NoSuchFieldException e) {
java6Available = false;
} catch (IllegalAccessException e) {
java6Available = false;
} catch (NoSuchMethodException e) {
java6Available = false;
}
try {
// sun.text.Normalizer.decompose(text, false, 0);
Class<?> normalizerClass = Thread.currentThread().getContextClassLoader()
.loadClass("sun.text.Normalizer");//$NON-NLS-1$
sunDecomposeMethod = normalizerClass.getMethod("decompose",
new Class[] {String.class, Boolean.TYPE, Integer.TYPE});//$NON-NLS-1$
sunAvailable = true;
} catch (ClassNotFoundException e) {
sunAvailable = false;
} catch (NoSuchMethodException e) {
sunAvailable = false;
}
}
// Equals
//-----------------------------------------------------------------------
/**
* <p>Compares two CharSequences, returning {@code true} if they are equal.</p>
*
* <p>{@code null}s are handled without exceptions. Two {@code null}
* references are considered to be equal. The comparison is case sensitive.</p>
*
* <pre>
* StringUtils.equals(null, null) = true
* StringUtils.equals(null, "abc") = false
* StringUtils.equals("abc", null) = false
* StringUtils.equals("abc", "abc") = true
* StringUtils.equals("abc", "ABC") = false
* </pre>
*
* @see java.lang.String#equals(Object)
* @param cs1 the first CharSequence, may be null
* @param cs2 the second CharSequence, may be null
* @return {@code true} if the CharSequences are equal, case sensitive, or
* both {@code null}
* @since 3.0 Changed signature from equals(String, String) to equals(CharSequence, CharSequence)
*/
public static boolean equals(CharSequence cs1, CharSequence cs2) {
return cs1 == null ? cs2 == null : cs1.equals(cs2);
}
/**
* <p>Compares two CharSequences, returning {@code true} if they are equal ignoring
* the case.</p>
*
* <p>{@code null}s are handled without exceptions. Two {@code null}
* references are considered equal. Comparison is case insensitive.</p>
*
* <pre>
* StringUtils.equalsIgnoreCase(null, null) = true
* StringUtils.equalsIgnoreCase(null, "abc") = false
* StringUtils.equalsIgnoreCase("abc", null) = false
* StringUtils.equalsIgnoreCase("abc", "abc") = true
* StringUtils.equalsIgnoreCase("abc", "ABC") = true
* </pre>
*
* @param str1 the first CharSequence, may be null
* @param str2 the second CharSequence, may be null
* @return {@code true} if the CharSequence are equal, case insensitive, or
* both {@code null}
* @since 3.0 Changed signature from equalsIgnoreCase(String, String) to equalsIgnoreCase(CharSequence, CharSequence)
*/
public static boolean equalsIgnoreCase(CharSequence str1, CharSequence str2) {
if (str1 == null || str2 == null) {
return str1 == str2;
} else {
return CharSequenceUtils.regionMatches(str1, true, 0, str2, 0, Math.max(str1.length(), str2.length()));
}
}
// IndexOf
//-----------------------------------------------------------------------
/**
* <p>Finds the first index within a CharSequence, handling {@code null}.
* This method uses {@link String#indexOf(int, int)} if possible.</p>
*
* <p>A {@code null} or empty ("") CharSequence will return {@code INDEX_NOT_FOUND (-1)}.</p>
*
* <pre>
* StringUtils.indexOf(null, *) = -1
* StringUtils.indexOf("", *) = -1
* StringUtils.indexOf("aabaabaa", 'a') = 0
* StringUtils.indexOf("aabaabaa", 'b') = 2
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchChar the character to find
* @return the first index of the search character,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from indexOf(String, int) to indexOf(CharSequence, int)
*/
public static int indexOf(CharSequence seq, int searchChar) {
if (isEmpty(seq)) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.indexOf(seq, searchChar, 0);
}
/**
* <p>Finds the first index within a CharSequence from a start position,
* handling {@code null}.
* This method uses {@link String#indexOf(int, int)} if possible.</p>
*
* <p>A {@code null} or empty ("") CharSequence will return {@code (INDEX_NOT_FOUND) -1}.
* A negative start position is treated as zero.
* A start position greater than the string length returns {@code -1}.</p>
*
* <pre>
* StringUtils.indexOf(null, *, *) = -1
* StringUtils.indexOf("", *, *) = -1
* StringUtils.indexOf("aabaabaa", 'b', 0) = 2
* StringUtils.indexOf("aabaabaa", 'b', 3) = 5
* StringUtils.indexOf("aabaabaa", 'b', 9) = -1
* StringUtils.indexOf("aabaabaa", 'b', -1) = 2
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchChar the character to find
* @param startPos the start position, negative treated as zero
* @return the first index of the search character,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from indexOf(String, int, int) to indexOf(CharSequence, int, int)
*/
public static int indexOf(CharSequence seq, int searchChar, int startPos) {
if (isEmpty(seq)) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.indexOf(seq, searchChar, startPos);
}
/**
* <p>Finds the first index within a CharSequence, handling {@code null}.
* This method uses {@link String#indexOf(String, int)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.</p>
*
* <pre>
* StringUtils.indexOf(null, *) = -1
* StringUtils.indexOf(*, null) = -1
* StringUtils.indexOf("", "") = 0
* StringUtils.indexOf("", *) = -1 (except when * = "")
* StringUtils.indexOf("aabaabaa", "a") = 0
* StringUtils.indexOf("aabaabaa", "b") = 2
* StringUtils.indexOf("aabaabaa", "ab") = 1
* StringUtils.indexOf("aabaabaa", "") = 0
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchSeq the CharSequence to find, may be null
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from indexOf(String, String) to indexOf(CharSequence, CharSequence)
*/
public static int indexOf(CharSequence seq, CharSequence searchSeq) {
if (seq == null || searchSeq == null) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.indexOf(seq, searchSeq, 0);
}
/**
* <p>Finds the first index within a CharSequence, handling {@code null}.
* This method uses {@link String#indexOf(String, int)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A negative start position is treated as zero.
* An empty ("") search CharSequence always matches.
* A start position greater than the string length only matches
* an empty search CharSequence.</p>
*
* <pre>
* StringUtils.indexOf(null, *, *) = -1
* StringUtils.indexOf(*, null, *) = -1
* StringUtils.indexOf("", "", 0) = 0
* StringUtils.indexOf("", *, 0) = -1 (except when * = "")
* StringUtils.indexOf("aabaabaa", "a", 0) = 0
* StringUtils.indexOf("aabaabaa", "b", 0) = 2
* StringUtils.indexOf("aabaabaa", "ab", 0) = 1
* StringUtils.indexOf("aabaabaa", "b", 3) = 5
* StringUtils.indexOf("aabaabaa", "b", 9) = -1
* StringUtils.indexOf("aabaabaa", "b", -1) = 2
* StringUtils.indexOf("aabaabaa", "", 2) = 2
* StringUtils.indexOf("abc", "", 9) = 3
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchSeq the CharSequence to find, may be null
* @param startPos the start position, negative treated as zero
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from indexOf(String, String, int) to indexOf(CharSequence, CharSequence, int)
*/
public static int indexOf(CharSequence seq, CharSequence searchSeq, int startPos) {
if (seq == null || searchSeq == null) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.indexOf(seq, searchSeq, startPos);
}
/**
* <p>Finds the n-th index within a CharSequence, handling {@code null}.
* This method uses {@link String#indexOf(String)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.</p>
*
* <pre>
* StringUtils.ordinalIndexOf(null, *, *) = -1
* StringUtils.ordinalIndexOf(*, null, *) = -1
* StringUtils.ordinalIndexOf("", "", *) = 0
* StringUtils.ordinalIndexOf("aabaabaa", "a", 1) = 0
* StringUtils.ordinalIndexOf("aabaabaa", "a", 2) = 1
* StringUtils.ordinalIndexOf("aabaabaa", "b", 1) = 2
* StringUtils.ordinalIndexOf("aabaabaa", "b", 2) = 5
* StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
* StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
* StringUtils.ordinalIndexOf("aabaabaa", "", 1) = 0
* StringUtils.ordinalIndexOf("aabaabaa", "", 2) = 0
* </pre>
*
* <p>Note that 'head(CharSequence str, int n)' may be implemented as: </p>
*
* <pre>
* str.substring(0, lastOrdinalIndexOf(str, "\n", n))
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @param ordinal the n-th {@code searchStr} to find
* @return the n-th index of the search CharSequence,
* {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
* @since 2.1
* @since 3.0 Changed signature from ordinalIndexOf(String, String, int) to ordinalIndexOf(CharSequence, CharSequence, int)
*/
public static int ordinalIndexOf(CharSequence str, CharSequence searchStr, int ordinal) {
return ordinalIndexOf(str, searchStr, ordinal, false);
}
/**
* <p>Finds the n-th index within a String, handling {@code null}.
* This method uses {@link String#indexOf(String)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.</p>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @param ordinal the n-th {@code searchStr} to find
* @param lastIndex true if lastOrdinalIndexOf() otherwise false if ordinalIndexOf()
* @return the n-th index of the search CharSequence,
* {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
*/
// Shared code between ordinalIndexOf(String,String,int) and lastOrdinalIndexOf(String,String,int)
private static int ordinalIndexOf(CharSequence str, CharSequence searchStr, int ordinal, boolean lastIndex) {
if (str == null || searchStr == null || ordinal <= 0) {
return INDEX_NOT_FOUND;
}
if (searchStr.length() == 0) {
return lastIndex ? str.length() : 0;
}
int found = 0;
int index = lastIndex ? str.length() : INDEX_NOT_FOUND;
do {
if (lastIndex) {
index = CharSequenceUtils.lastIndexOf(str, searchStr, index - 1);
} else {
index = CharSequenceUtils.indexOf(str, searchStr, index + 1);
}
if (index < 0) {
return index;
}
found++;
} while (found < ordinal);
return index;
}
/**
* <p>Case in-sensitive find of the first index within a CharSequence.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A negative start position is treated as zero.
* An empty ("") search CharSequence always matches.
* A start position greater than the string length only matches
* an empty search CharSequence.</p>
*
* <pre>
* StringUtils.indexOfIgnoreCase(null, *) = -1
* StringUtils.indexOfIgnoreCase(*, null) = -1
* StringUtils.indexOfIgnoreCase("", "") = 0
* StringUtils.indexOfIgnoreCase("aabaabaa", "a") = 0
* StringUtils.indexOfIgnoreCase("aabaabaa", "b") = 2
* StringUtils.indexOfIgnoreCase("aabaabaa", "ab") = 1
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} string input
* @since 2.5
* @since 3.0 Changed signature from indexOfIgnoreCase(String, String) to indexOfIgnoreCase(CharSequence, CharSequence)
*/
public static int indexOfIgnoreCase(CharSequence str, CharSequence searchStr) {
return indexOfIgnoreCase(str, searchStr, 0);
}
/**
* <p>Case in-sensitive find of the first index within a CharSequence
* from the specified position.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A negative start position is treated as zero.
* An empty ("") search CharSequence always matches.
* A start position greater than the string length only matches
* an empty search CharSequence.</p>
*
* <pre>
* StringUtils.indexOfIgnoreCase(null, *, *) = -1
* StringUtils.indexOfIgnoreCase(*, null, *) = -1
* StringUtils.indexOfIgnoreCase("", "", 0) = 0
* StringUtils.indexOfIgnoreCase("aabaabaa", "A", 0) = 0
* StringUtils.indexOfIgnoreCase("aabaabaa", "B", 0) = 2
* StringUtils.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
* StringUtils.indexOfIgnoreCase("aabaabaa", "B", 3) = 5
* StringUtils.indexOfIgnoreCase("aabaabaa", "B", 9) = -1
* StringUtils.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
* StringUtils.indexOfIgnoreCase("aabaabaa", "", 2) = 2
* StringUtils.indexOfIgnoreCase("abc", "", 9) = 3
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @param startPos the start position, negative treated as zero
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} string input
* @since 2.5
* @since 3.0 Changed signature from indexOfIgnoreCase(String, String, int) to indexOfIgnoreCase(CharSequence, CharSequence, int)
*/
public static int indexOfIgnoreCase(CharSequence str, CharSequence searchStr, int startPos) {
if (str == null || searchStr == null) {
return INDEX_NOT_FOUND;
}
if (startPos < 0) {
startPos = 0;
}
int endLimit = (str.length() - searchStr.length()) + 1;
if (startPos > endLimit) {
return INDEX_NOT_FOUND;
}
if (searchStr.length() == 0) {
return startPos;
}
for (int i = startPos; i < endLimit; i++) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, searchStr.length())) {
return i;
}
}
return INDEX_NOT_FOUND;
}
// LastIndexOf
//-----------------------------------------------------------------------
/**
* <p>Finds the last index within a CharSequence, handling {@code null}.
* This method uses {@link String#lastIndexOf(int)} if possible.</p>
*
* <p>A {@code null} or empty ("") CharSequence will return {@code -1}.</p>
*
* <pre>
* StringUtils.lastIndexOf(null, *) = -1
* StringUtils.lastIndexOf("", *) = -1
* StringUtils.lastIndexOf("aabaabaa", 'a') = 7
* StringUtils.lastIndexOf("aabaabaa", 'b') = 5
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchChar the character to find
* @return the last index of the search character,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from lastIndexOf(String, int) to lastIndexOf(CharSequence, int)
*/
public static int lastIndexOf(CharSequence seq, int searchChar) {
if (isEmpty(seq)) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.lastIndexOf(seq, searchChar, seq.length());
}
/**
* <p>Finds the last index within a CharSequence from a start position,
* handling {@code null}.
* This method uses {@link String#lastIndexOf(int, int)} if possible.</p>
*
* <p>A {@code null} or empty ("") CharSequence will return {@code -1}.
* A negative start position returns {@code -1}.
* A start position greater than the string length searches the whole string.</p>
*
* <pre>
* StringUtils.lastIndexOf(null, *, *) = -1
* StringUtils.lastIndexOf("", *, *) = -1
* StringUtils.lastIndexOf("aabaabaa", 'b', 8) = 5
* StringUtils.lastIndexOf("aabaabaa", 'b', 4) = 2
* StringUtils.lastIndexOf("aabaabaa", 'b', 0) = -1
* StringUtils.lastIndexOf("aabaabaa", 'b', 9) = 5
* StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
* StringUtils.lastIndexOf("aabaabaa", 'a', 0) = 0
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchChar the character to find
* @param startPos the start position
* @return the last index of the search character,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from lastIndexOf(String, int, int) to lastIndexOf(CharSequence, int, int)
*/
public static int lastIndexOf(CharSequence seq, int searchChar, int startPos) {
if (isEmpty(seq)) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.lastIndexOf(seq, searchChar, startPos);
}
/**
* <p>Finds the last index within a CharSequence, handling {@code null}.
* This method uses {@link String#lastIndexOf(String)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.</p>
*
* <pre>
* StringUtils.lastIndexOf(null, *) = -1
* StringUtils.lastIndexOf(*, null) = -1
* StringUtils.lastIndexOf("", "") = 0
* StringUtils.lastIndexOf("aabaabaa", "a") = 7
* StringUtils.lastIndexOf("aabaabaa", "b") = 5
* StringUtils.lastIndexOf("aabaabaa", "ab") = 4
* StringUtils.lastIndexOf("aabaabaa", "") = 8
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchSeq the CharSequence to find, may be null
* @return the last index of the search String,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from lastIndexOf(String, String) to lastIndexOf(CharSequence, CharSequence)
*/
public static int lastIndexOf(CharSequence seq, CharSequence searchSeq) {
if (seq == null || searchSeq == null) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.lastIndexOf(seq, searchSeq, seq.length());
}
/**
* <p>Finds the n-th last index within a String, handling {@code null}.
* This method uses {@link String#lastIndexOf(String)}.</p>
*
* <p>A {@code null} String will return {@code -1}.</p>
*
* <pre>
* StringUtils.lastOrdinalIndexOf(null, *, *) = -1
* StringUtils.lastOrdinalIndexOf(*, null, *) = -1
* StringUtils.lastOrdinalIndexOf("", "", *) = 0
* StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1) = 7
* StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2) = 6
* StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1) = 5
* StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2) = 2
* StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) = 4
* StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) = 1
* StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1) = 8
* StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2) = 8
* </pre>
*
* <p>Note that 'tail(CharSequence str, int n)' may be implemented as: </p>
*
* <pre>
* str.substring(lastOrdinalIndexOf(str, "\n", n) + 1)
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @param ordinal the n-th last {@code searchStr} to find
* @return the n-th last index of the search CharSequence,
* {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
* @since 2.5
* @since 3.0 Changed signature from lastOrdinalIndexOf(String, String, int) to lastOrdinalIndexOf(CharSequence, CharSequence, int)
*/
public static int lastOrdinalIndexOf(CharSequence str, CharSequence searchStr, int ordinal) {
return ordinalIndexOf(str, searchStr, ordinal, true);
}
/**
* <p>Finds the first index within a CharSequence, handling {@code null}.
* This method uses {@link String#lastIndexOf(String, int)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A negative start position returns {@code -1}.
* An empty ("") search CharSequence always matches unless the start position is negative.
* A start position greater than the string length searches the whole string.</p>
*
* <pre>
* StringUtils.lastIndexOf(null, *, *) = -1
* StringUtils.lastIndexOf(*, null, *) = -1
* StringUtils.lastIndexOf("aabaabaa", "a", 8) = 7
* StringUtils.lastIndexOf("aabaabaa", "b", 8) = 5
* StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
* StringUtils.lastIndexOf("aabaabaa", "b", 9) = 5
* StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
* StringUtils.lastIndexOf("aabaabaa", "a", 0) = 0
* StringUtils.lastIndexOf("aabaabaa", "b", 0) = -1
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchSeq the CharSequence to find, may be null
* @param startPos the start position, negative treated as zero
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from lastIndexOf(String, String, int) to lastIndexOf(CharSequence, CharSequence, int)
*/
public static int lastIndexOf(CharSequence seq, CharSequence searchSeq, int startPos) {
if (seq == null || searchSeq == null) {
return INDEX_NOT_FOUND;
}
return CharSequenceUtils.lastIndexOf(seq, searchSeq, startPos);
}
/**
* <p>Case in-sensitive find of the last index within a CharSequence.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A negative start position returns {@code -1}.
* An empty ("") search CharSequence always matches unless the start position is negative.
* A start position greater than the string length searches the whole string.</p>
*
* <pre>
* StringUtils.lastIndexOfIgnoreCase(null, *) = -1
* StringUtils.lastIndexOfIgnoreCase(*, null) = -1
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A") = 7
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B") = 5
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB") = 4
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} string input
* @since 2.5
* @since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String) to lastIndexOfIgnoreCase(CharSequence, CharSequence)
*/
public static int lastIndexOfIgnoreCase(CharSequence str, CharSequence searchStr) {
if (str == null || searchStr == null) {
return INDEX_NOT_FOUND;
}
return lastIndexOfIgnoreCase(str, searchStr, str.length());
}
/**
* <p>Case in-sensitive find of the last index within a CharSequence
* from the specified position.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A negative start position returns {@code -1}.
* An empty ("") search CharSequence always matches unless the start position is negative.
* A start position greater than the string length searches the whole string.</p>
*
* <pre>
* StringUtils.lastIndexOfIgnoreCase(null, *, *) = -1
* StringUtils.lastIndexOfIgnoreCase(*, null, *) = -1
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 8) = 7
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 8) = 5
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB", 8) = 4
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 9) = 5
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", -1) = -1
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 0) = 0
* StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 0) = -1
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @param startPos the start position
* @return the first index of the search CharSequence,
* -1 if no match or {@code null} input
* @since 2.5
* @since 3.0 Changed signature from lastIndexOfIgnoreCase(String, String, int) to lastIndexOfIgnoreCase(CharSequence, CharSequence, int)
*/
public static int lastIndexOfIgnoreCase(CharSequence str, CharSequence searchStr, int startPos) {
if (str == null || searchStr == null) {
return INDEX_NOT_FOUND;
}
if (startPos > (str.length() - searchStr.length())) {
startPos = str.length() - searchStr.length();
}
if (startPos < 0) {
return INDEX_NOT_FOUND;
}
if (searchStr.length() == 0) {
return startPos;
}
for (int i = startPos; i >= 0; i--) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, searchStr.length())) {
return i;
}
}
return INDEX_NOT_FOUND;
}
// Contains
//-----------------------------------------------------------------------
/**
* <p>Checks if CharSequence contains a search character, handling {@code null}.
* This method uses {@link String#indexOf(int)} if possible.</p>
*
* <p>A {@code null} or empty ("") CharSequence will return {@code false}.</p>
*
* <pre>
* StringUtils.contains(null, *) = false
* StringUtils.contains("", *) = false
* StringUtils.contains("abc", 'a') = true
* StringUtils.contains("abc", 'z') = false
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchChar the character to find
* @return true if the CharSequence contains the search character,
* false if not or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from contains(String, int) to contains(CharSequence, int)
*/
public static boolean contains(CharSequence seq, int searchChar) {
if (isEmpty(seq)) {
return false;
}
return CharSequenceUtils.indexOf(seq, searchChar, 0) >= 0;
}
/**
* <p>Checks if CharSequence contains a search CharSequence, handling {@code null}.
* This method uses {@link String#indexOf(String)} if possible.</p>
*
* <p>A {@code null} CharSequence will return {@code false}.</p>
*
* <pre>
* StringUtils.contains(null, *) = false
* StringUtils.contains(*, null) = false
* StringUtils.contains("", "") = true
* StringUtils.contains("abc", "") = true
* StringUtils.contains("abc", "a") = true
* StringUtils.contains("abc", "z") = false
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchSeq the CharSequence to find, may be null
* @return true if the CharSequence contains the search CharSequence,
* false if not or {@code null} string input
* @since 2.0
* @since 3.0 Changed signature from contains(String, String) to contains(CharSequence, CharSequence)
*/
public static boolean contains(CharSequence seq, CharSequence searchSeq) {
if (seq == null || searchSeq == null) {
return false;
}
return CharSequenceUtils.indexOf(seq, searchSeq, 0) >= 0;
}
/**
* <p>Checks if CharSequence contains a search CharSequence irrespective of case,
* handling {@code null}. Case-insensitivity is defined as by
* {@link String#equalsIgnoreCase(String)}.
*
* <p>A {@code null} CharSequence will return {@code false}.</p>
*
* <pre>
* StringUtils.contains(null, *) = false
* StringUtils.contains(*, null) = false
* StringUtils.contains("", "") = true
* StringUtils.contains("abc", "") = true
* StringUtils.contains("abc", "a") = true
* StringUtils.contains("abc", "z") = false
* StringUtils.contains("abc", "A") = true
* StringUtils.contains("abc", "Z") = false
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStr the CharSequence to find, may be null
* @return true if the CharSequence contains the search CharSequence irrespective of
* case or false if not or {@code null} string input
* @since 3.0 Changed signature from containsIgnoreCase(String, String) to containsIgnoreCase(CharSequence, CharSequence)
*/
public static boolean containsIgnoreCase(CharSequence str, CharSequence searchStr) {
if (str == null || searchStr == null) {
return false;
}
int len = searchStr.length();
int max = str.length() - len;
for (int i = 0; i <= max; i++) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
return true;
}
}
return false;
}
/**
* Check whether the given CharSequence contains any whitespace characters.
* @param seq the CharSequence to check (may be {@code null})
* @return {@code true} if the CharSequence is not empty and
* contains at least 1 whitespace character
* @see java.lang.Character#isWhitespace
* @since 3.0
*/
// From org.springframework.util.StringUtils, under Apache License 2.0
public static boolean containsWhitespace(CharSequence seq) {
if (isEmpty(seq)) {
return false;
}
int strLen = seq.length();
for (int i = 0; i < strLen; i++) {
if (Character.isWhitespace(seq.charAt(i))) {
return true;
}
}
return false;
}
// IndexOfAny chars
//-----------------------------------------------------------------------
/**
* <p>Search a CharSequence to find the first index of any
* character in the given set of characters.</p>
*
* <p>A {@code null} String will return {@code -1}.
* A {@code null} or zero length search array will return {@code -1}.</p>
*
* <pre>
* StringUtils.indexOfAny(null, *) = -1
* StringUtils.indexOfAny("", *) = -1
* StringUtils.indexOfAny(*, null) = -1
* StringUtils.indexOfAny(*, []) = -1
* StringUtils.indexOfAny("zzabyycdxx",['z','a']) = 0
* StringUtils.indexOfAny("zzabyycdxx",['b','y']) = 3
* StringUtils.indexOfAny("aba", ['z']) = -1
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param searchChars the chars to search for, may be null
* @return the index of any of the chars, -1 if no match or null input
* @since 2.0
* @since 3.0 Changed signature from indexOfAny(String, char[]) to indexOfAny(CharSequence, char...)
*/
public static int indexOfAny(CharSequence cs, char... searchChars) {
if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
return INDEX_NOT_FOUND;
}
int csLen = cs.length();
int csLast = csLen - 1;
int searchLen = searchChars.length;
int searchLast = searchLen - 1;
for (int i = 0; i < csLen; i++) {
char ch = cs.charAt(i);
for (int j = 0; j < searchLen; j++) {
if (searchChars[j] == ch) {
if (i < csLast && j < searchLast && Character.isHighSurrogate(ch)) {
// ch is a supplementary character
if (searchChars[j + 1] == cs.charAt(i + 1)) {
return i;
}
} else {
return i;
}
}
}
}
return INDEX_NOT_FOUND;
}
/**
* <p>Search a CharSequence to find the first index of any
* character in the given set of characters.</p>
*
* <p>A {@code null} String will return {@code -1}.
* A {@code null} search string will return {@code -1}.</p>
*
* <pre>
* StringUtils.indexOfAny(null, *) = -1
* StringUtils.indexOfAny("", *) = -1
* StringUtils.indexOfAny(*, null) = -1
* StringUtils.indexOfAny(*, "") = -1
* StringUtils.indexOfAny("zzabyycdxx", "za") = 0
* StringUtils.indexOfAny("zzabyycdxx", "by") = 3
* StringUtils.indexOfAny("aba","z") = -1
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param searchChars the chars to search for, may be null
* @return the index of any of the chars, -1 if no match or null input
* @since 2.0
* @since 3.0 Changed signature from indexOfAny(String, String) to indexOfAny(CharSequence, String)
*/
public static int indexOfAny(CharSequence cs, String searchChars) {
if (isEmpty(cs) || isEmpty(searchChars)) {
return INDEX_NOT_FOUND;
}
return indexOfAny(cs, searchChars.toCharArray());
}
// ContainsAny
//-----------------------------------------------------------------------
/**
* <p>Checks if the CharSequence contains any character in the given
* set of characters.</p>
*
* <p>A {@code null} CharSequence will return {@code false}.
* A {@code null} or zero length search array will return {@code false}.</p>
*
* <pre>
* StringUtils.containsAny(null, *) = false
* StringUtils.containsAny("", *) = false
* StringUtils.containsAny(*, null) = false
* StringUtils.containsAny(*, []) = false
* StringUtils.containsAny("zzabyycdxx",['z','a']) = true
* StringUtils.containsAny("zzabyycdxx",['b','y']) = true
* StringUtils.containsAny("aba", ['z']) = false
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param searchChars the chars to search for, may be null
* @return the {@code true} if any of the chars are found,
* {@code false} if no match or null input
* @since 2.4
* @since 3.0 Changed signature from containsAny(String, char[]) to containsAny(CharSequence, char...)
*/
public static boolean containsAny(CharSequence cs, char... searchChars) {
if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
return false;
}
int csLength = cs.length();
int searchLength = searchChars.length;
int csLast = csLength - 1;
int searchLast = searchLength - 1;
for (int i = 0; i < csLength; i++) {
char ch = cs.charAt(i);
for (int j = 0; j < searchLength; j++) {
if (searchChars[j] == ch) {
if (Character.isHighSurrogate(ch)) {
if (j == searchLast) {
// missing low surrogate, fine, like String.indexOf(String)
return true;
}
if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
return true;
}
} else {
// ch is in the Basic Multilingual Plane
return true;
}
}
}
}
return false;
}
/**
* <p>
* Checks if the CharSequence contains any character in the given set of characters.
* </p>
*
* <p>
* A {@code null} CharSequence will return {@code false}. A {@code null} search CharSequence will return
* {@code false}.
* </p>
*
* <pre>
* StringUtils.containsAny(null, *) = false
* StringUtils.containsAny("", *) = false
* StringUtils.containsAny(*, null) = false
* StringUtils.containsAny(*, "") = false
* StringUtils.containsAny("zzabyycdxx", "za") = true
* StringUtils.containsAny("zzabyycdxx", "by") = true
* StringUtils.containsAny("aba","z") = false
* </pre>
*
* @param cs
* the CharSequence to check, may be null
* @param searchChars
* the chars to search for, may be null
* @return the {@code true} if any of the chars are found, {@code false} if no match or null input
* @since 2.4
* @since 3.0 Changed signature from containsAny(String, String) to containsAny(CharSequence, CharSequence)
*/
public static boolean containsAny(CharSequence cs, CharSequence searchChars) {
if (searchChars == null) {
return false;
}
return containsAny(cs, CharSequenceUtils.toCharArray(searchChars));
}
// IndexOfAnyBut chars
//-----------------------------------------------------------------------
/**
* <p>Searches a CharSequence to find the first index of any
* character not in the given set of characters.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A {@code null} or zero length search array will return {@code -1}.</p>
*
* <pre>
* StringUtils.indexOfAnyBut(null, *) = -1
* StringUtils.indexOfAnyBut("", *) = -1
* StringUtils.indexOfAnyBut(*, null) = -1
* StringUtils.indexOfAnyBut(*, []) = -1
* StringUtils.indexOfAnyBut("zzabyycdxx", new char[] {'z', 'a'} ) = 3
* StringUtils.indexOfAnyBut("aba", new char[] {'z'} ) = 0
* StringUtils.indexOfAnyBut("aba", new char[] {'a', 'b'} ) = -1
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param searchChars the chars to search for, may be null
* @return the index of any of the chars, -1 if no match or null input
* @since 2.0
* @since 3.0 Changed signature from indexOfAnyBut(String, char[]) to indexOfAnyBut(CharSequence, char...)
*/
public static int indexOfAnyBut(CharSequence cs, char... searchChars) {
if (isEmpty(cs) || ArrayUtils.isEmpty(searchChars)) {
return INDEX_NOT_FOUND;
}
int csLen = cs.length();
int csLast = csLen - 1;
int searchLen = searchChars.length;
int searchLast = searchLen - 1;
outer:
for (int i = 0; i < csLen; i++) {
char ch = cs.charAt(i);
for (int j = 0; j < searchLen; j++) {
if (searchChars[j] == ch) {
if (i < csLast && j < searchLast && Character.isHighSurrogate(ch)) {
if (searchChars[j + 1] == cs.charAt(i + 1)) {
continue outer;
}
} else {
continue outer;
}
}
}
return i;
}
return INDEX_NOT_FOUND;
}
/**
* <p>Search a CharSequence to find the first index of any
* character not in the given set of characters.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A {@code null} or empty search string will return {@code -1}.</p>
*
* <pre>
* StringUtils.indexOfAnyBut(null, *) = -1
* StringUtils.indexOfAnyBut("", *) = -1
* StringUtils.indexOfAnyBut(*, null) = -1
* StringUtils.indexOfAnyBut(*, "") = -1
* StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
* StringUtils.indexOfAnyBut("zzabyycdxx", "") = -1
* StringUtils.indexOfAnyBut("aba","ab") = -1
* </pre>
*
* @param seq the CharSequence to check, may be null
* @param searchChars the chars to search for, may be null
* @return the index of any of the chars, -1 if no match or null input
* @since 2.0
* @since 3.0 Changed signature from indexOfAnyBut(String, String) to indexOfAnyBut(CharSequence, CharSequence)
*/
public static int indexOfAnyBut(CharSequence seq, CharSequence searchChars) {
if (isEmpty(seq) || isEmpty(searchChars)) {
return INDEX_NOT_FOUND;
}
int strLen = seq.length();
for (int i = 0; i < strLen; i++) {
char ch = seq.charAt(i);
boolean chFound = CharSequenceUtils.indexOf(searchChars, ch, 0) >= 0;
if (i + 1 < strLen && Character.isHighSurrogate(ch)) {
char ch2 = seq.charAt(i + 1);
if (chFound && CharSequenceUtils.indexOf(searchChars, ch2, 0) < 0) {
return i;
}
} else {
if (!chFound) {
return i;
}
}
}
return INDEX_NOT_FOUND;
}
// ContainsOnly
//-----------------------------------------------------------------------
/**
* <p>Checks if the CharSequence contains only certain characters.</p>
*
* <p>A {@code null} CharSequence will return {@code false}.
* A {@code null} valid character array will return {@code false}.
* An empty CharSequence (length()=0) always returns {@code true}.</p>
*
* <pre>
* StringUtils.containsOnly(null, *) = false
* StringUtils.containsOnly(*, null) = false
* StringUtils.containsOnly("", *) = true
* StringUtils.containsOnly("ab", '') = false
* StringUtils.containsOnly("abab", 'abc') = true
* StringUtils.containsOnly("ab1", 'abc') = false
* StringUtils.containsOnly("abz", 'abc') = false
* </pre>
*
* @param cs the String to check, may be null
* @param valid an array of valid chars, may be null
* @return true if it only contains valid chars and is non-null
* @since 3.0 Changed signature from containsOnly(String, char[]) to containsOnly(CharSequence, char...)
*/
public static boolean containsOnly(CharSequence cs, char... valid) {
// All these pre-checks are to maintain API with an older version
if (valid == null || cs == null) {
return false;
}
if (cs.length() == 0) {
return true;
}
if (valid.length == 0) {
return false;
}
return indexOfAnyBut(cs, valid) == INDEX_NOT_FOUND;
}
/**
* <p>Checks if the CharSequence contains only certain characters.</p>
*
* <p>A {@code null} CharSequence will return {@code false}.
* A {@code null} valid character String will return {@code false}.
* An empty String (length()=0) always returns {@code true}.</p>
*
* <pre>
* StringUtils.containsOnly(null, *) = false
* StringUtils.containsOnly(*, null) = false
* StringUtils.containsOnly("", *) = true
* StringUtils.containsOnly("ab", "") = false
* StringUtils.containsOnly("abab", "abc") = true
* StringUtils.containsOnly("ab1", "abc") = false
* StringUtils.containsOnly("abz", "abc") = false
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param validChars a String of valid chars, may be null
* @return true if it only contains valid chars and is non-null
* @since 2.0
* @since 3.0 Changed signature from containsOnly(String, String) to containsOnly(CharSequence, String)
*/
public static boolean containsOnly(CharSequence cs, String validChars) {
if (cs == null || validChars == null) {
return false;
}
return containsOnly(cs, validChars.toCharArray());
}
// ContainsNone
//-----------------------------------------------------------------------
/**
* <p>Checks that the CharSequence does not contain certain characters.</p>
*
* <p>A {@code null} CharSequence will return {@code true}.
* A {@code null} invalid character array will return {@code true}.
* An empty CharSequence (length()=0) always returns true.</p>
*
* <pre>
* StringUtils.containsNone(null, *) = true
* StringUtils.containsNone(*, null) = true
* StringUtils.containsNone("", *) = true
* StringUtils.containsNone("ab", '') = true
* StringUtils.containsNone("abab", 'xyz') = true
* StringUtils.containsNone("ab1", 'xyz') = true
* StringUtils.containsNone("abz", 'xyz') = false
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param searchChars an array of invalid chars, may be null
* @return true if it contains none of the invalid chars, or is null
* @since 2.0
* @since 3.0 Changed signature from containsNone(String, char[]) to containsNone(CharSequence, char...)
*/
public static boolean containsNone(CharSequence cs, char... searchChars) {
if (cs == null || searchChars == null) {
return true;
}
int csLen = cs.length();
int csLast = csLen - 1;
int searchLen = searchChars.length;
int searchLast = searchLen - 1;
for (int i = 0; i < csLen; i++) {
char ch = cs.charAt(i);
for (int j = 0; j < searchLen; j++) {
if (searchChars[j] == ch) {
if (Character.isHighSurrogate(ch)) {
if (j == searchLast) {
// missing low surrogate, fine, like String.indexOf(String)
return false;
}
if (i < csLast && searchChars[j + 1] == cs.charAt(i + 1)) {
return false;
}
} else {
// ch is in the Basic Multilingual Plane
return false;
}
}
}
}
return true;
}
/**
* <p>Checks that the CharSequence does not contain certain characters.</p>
*
* <p>A {@code null} CharSequence will return {@code true}.
* A {@code null} invalid character array will return {@code true}.
* An empty String ("") always returns true.</p>
*
* <pre>
* StringUtils.containsNone(null, *) = true
* StringUtils.containsNone(*, null) = true
* StringUtils.containsNone("", *) = true
* StringUtils.containsNone("ab", "") = true
* StringUtils.containsNone("abab", "xyz") = true
* StringUtils.containsNone("ab1", "xyz") = true
* StringUtils.containsNone("abz", "xyz") = false
* </pre>
*
* @param cs the CharSequence to check, may be null
* @param invalidChars a String of invalid chars, may be null
* @return true if it contains none of the invalid chars, or is null
* @since 2.0
* @since 3.0 Changed signature from containsNone(String, String) to containsNone(CharSequence, String)
*/
public static boolean containsNone(CharSequence cs, String invalidChars) {
if (cs == null || invalidChars == null) {
return true;
}
return containsNone(cs, invalidChars.toCharArray());
}
// IndexOfAny strings
//-----------------------------------------------------------------------
/**
* <p>Find the first index of any of a set of potential substrings.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A {@code null} or zero length search array will return {@code -1}.
* A {@code null} search array entry will be ignored, but a search
* array containing "" will return {@code 0} if {@code str} is not
* null. This method uses {@link String#indexOf(String)} if possible.</p>
*
* <pre>
* StringUtils.indexOfAny(null, *) = -1
* StringUtils.indexOfAny(*, null) = -1
* StringUtils.indexOfAny(*, []) = -1
* StringUtils.indexOfAny("zzabyycdxx", ["ab","cd"]) = 2
* StringUtils.indexOfAny("zzabyycdxx", ["cd","ab"]) = 2
* StringUtils.indexOfAny("zzabyycdxx", ["mn","op"]) = -1
* StringUtils.indexOfAny("zzabyycdxx", ["zab","aby"]) = 1
* StringUtils.indexOfAny("zzabyycdxx", [""]) = 0
* StringUtils.indexOfAny("", [""]) = 0
* StringUtils.indexOfAny("", ["a"]) = -1
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStrs the CharSequences to search for, may be null
* @return the first index of any of the searchStrs in str, -1 if no match
* @since 3.0 Changed signature from indexOfAny(String, String[]) to indexOfAny(CharSequence, CharSequence...)
*/
public static int indexOfAny(CharSequence str, CharSequence... searchStrs) {
if (str == null || searchStrs == null) {
return INDEX_NOT_FOUND;
}
int sz = searchStrs.length;
// String's can't have a MAX_VALUEth index.
int ret = Integer.MAX_VALUE;
int tmp = 0;
for (int i = 0; i < sz; i++) {
CharSequence search = searchStrs[i];
if (search == null) {
continue;
}
tmp = CharSequenceUtils.indexOf(str, search, 0);
if (tmp == INDEX_NOT_FOUND) {
continue;
}
if (tmp < ret) {
ret = tmp;
}
}
return (ret == Integer.MAX_VALUE) ? INDEX_NOT_FOUND : ret;
}
/**
* <p>Find the latest index of any of a set of potential substrings.</p>
*
* <p>A {@code null} CharSequence will return {@code -1}.
* A {@code null} search array will return {@code -1}.
* A {@code null} or zero length search array entry will be ignored,
* but a search array containing "" will return the length of {@code str}
* if {@code str} is not null. This method uses {@link String#indexOf(String)} if possible</p>
*
* <pre>
* StringUtils.lastIndexOfAny(null, *) = -1
* StringUtils.lastIndexOfAny(*, null) = -1
* StringUtils.lastIndexOfAny(*, []) = -1
* StringUtils.lastIndexOfAny(*, [null]) = -1
* StringUtils.lastIndexOfAny("zzabyycdxx", ["ab","cd"]) = 6
* StringUtils.lastIndexOfAny("zzabyycdxx", ["cd","ab"]) = 6
* StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
* StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
* StringUtils.lastIndexOfAny("zzabyycdxx", ["mn",""]) = 10
* </pre>
*
* @param str the CharSequence to check, may be null
* @param searchStrs the CharSequences to search for, may be null
* @return the last index of any of the CharSequences, -1 if no match
* @since 3.0 Changed signature from lastIndexOfAny(String, String[]) to lastIndexOfAny(CharSequence, CharSequence)
*/
public static int lastIndexOfAny(CharSequence str, CharSequence... searchStrs) {
if (str == null || searchStrs == null) {
return INDEX_NOT_FOUND;
}
int sz = searchStrs.length;
int ret = INDEX_NOT_FOUND;
int tmp = 0;
for (int i = 0; i < sz; i++) {
CharSequence search = searchStrs[i];
if (search == null) {
continue;
}
tmp = CharSequenceUtils.lastIndexOf(str, search, str.length());
if (tmp > ret) {
ret = tmp;
}
}
return ret;
}
// Substring
//-----------------------------------------------------------------------
/**
* <p>Gets a substring from the specified String avoiding exceptions.</p>
*
* <p>A negative start position can be used to start {@code n}
* characters from the end of the String.</p>
*
* <p>A {@code null} String will return {@code null}.
* An empty ("") String will return "".</p>
*
* <pre>
* StringUtils.substring(null, *) = null
* StringUtils.substring("", *) = ""
* StringUtils.substring("abc", 0) = "abc"
* StringUtils.substring("abc", 2) = "c"
* StringUtils.substring("abc", 4) = ""
* StringUtils.substring("abc", -2) = "bc"
* StringUtils.substring("abc", -4) = "abc"
* </pre>
*
* @param str the String to get the substring from, may be null
* @param start the position to start from, negative means
* count back from the end of the String by this many characters
* @return substring from start position, {@code null} if null String input
*/
public static String substring(String str, int start) {
if (str == null) {
return null;
}
// handle negatives, which means last n characters
if (start < 0) {
start = str.length() + start; // remember start is negative
}
if (start < 0) {
start = 0;
}
if (start > str.length()) {
return EMPTY;
}
return str.substring(start);
}
/**
* <p>Gets a substring from the specified String avoiding exceptions.</p>
*
* <p>A negative start position can be used to start/end {@code n}
* characters from the end of the String.</p>
*
* <p>The returned substring starts with the character in the {@code start}
* position and ends before the {@code end} position. All position counting is
* zero-based -- i.e., to start at the beginning of the string use
* {@code start = 0}. Negative start and end positions can be used to
* specify offsets relative to the end of the String.</p>
*
* <p>If {@code start} is not strictly to the left of {@code end}, ""
* is returned.</p>
*
* <pre>
* StringUtils.substring(null, *, *) = null
* StringUtils.substring("", * , *) = "";
* StringUtils.substring("abc", 0, 2) = "ab"
* StringUtils.substring("abc", 2, 0) = ""
* StringUtils.substring("abc", 2, 4) = "c"
* StringUtils.substring("abc", 4, 6) = ""
* StringUtils.substring("abc", 2, 2) = ""
* StringUtils.substring("abc", -2, -1) = "b"
* StringUtils.substring("abc", -4, 2) = "ab"
* </pre>
*
* @param str the String to get the substring from, may be null
* @param start the position to start from, negative means
* count back from the end of the String by this many characters
* @param end the position to end at (exclusive), negative means
* count back from the end of the String by this many characters
* @return substring from start position to end position,
* {@code null} if null String input
*/
public static String substring(String str, int start, int end) {
if (str == null) {
return null;
}
// handle negatives
if (end < 0) {
end = str.length() + end; // remember end is negative
}
if (start < 0) {
start = str.length() + start; // remember start is negative
}
// check length next
if (end > str.length()) {
end = str.length();
}
// if start is greater than end, return ""
if (start > end) {
return EMPTY;
}
if (start < 0) {
start = 0;
}
if (end < 0) {
end = 0;
}
return str.substring(start, end);
}
// Left/Right/Mid
//-----------------------------------------------------------------------
/**
* <p>Gets the leftmost {@code len} characters of a String.</p>
*
* <p>If {@code len} characters are not available, or the
* String is {@code null}, the String will be returned without
* an exception. An empty String is returned if len is negative.</p>
*
* <pre>
* StringUtils.left(null, *) = null
* StringUtils.left(*, -ve) = ""
* StringUtils.left("", *) = ""
* StringUtils.left("abc", 0) = ""
* StringUtils.left("abc", 2) = "ab"
* StringUtils.left("abc", 4) = "abc"
* </pre>
*
* @param str the String to get the leftmost characters from, may be null
* @param len the length of the required String
* @return the leftmost characters, {@code null} if null String input
*/
public static String left(String str, int len) {
if (str == null) {
return null;
}
if (len < 0) {
return EMPTY;
}
if (str.length() <= len) {
return str;
}
return str.substring(0, len);
}
/**
* <p>Gets the rightmost {@code len} characters of a String.</p>
*
* <p>If {@code len} characters are not available, or the String
* is {@code null}, the String will be returned without an
* an exception. An empty String is returned if len is negative.</p>
*
* <pre>
* StringUtils.right(null, *) = null
* StringUtils.right(*, -ve) = ""
* StringUtils.right("", *) = ""
* StringUtils.right("abc", 0) = ""
* StringUtils.right("abc", 2) = "bc"
* StringUtils.right("abc", 4) = "abc"
* </pre>
*
* @param str the String to get the rightmost characters from, may be null
* @param len the length of the required String
* @return the rightmost characters, {@code null} if null String input
*/
public static String right(String str, int len) {
if (str == null) {
return null;
}
if (len < 0) {
return EMPTY;
}
if (str.length() <= len) {
return str;
}
return str.substring(str.length() - len);
}
/**
* <p>Gets {@code len} characters from the middle of a String.</p>
*
* <p>If {@code len} characters are not available, the remainder
* of the String will be returned without an exception. If the
* String is {@code null}, {@code null} will be returned.
* An empty String is returned if len is negative or exceeds the
* length of {@code str}.</p>
*
* <pre>
* StringUtils.mid(null, *, *) = null
* StringUtils.mid(*, *, -ve) = ""
* StringUtils.mid("", 0, *) = ""
* StringUtils.mid("abc", 0, 2) = "ab"
* StringUtils.mid("abc", 0, 4) = "abc"
* StringUtils.mid("abc", 2, 4) = "c"
* StringUtils.mid("abc", 4, 2) = ""
* StringUtils.mid("abc", -2, 2) = "ab"
* </pre>
*
* @param str the String to get the characters from, may be null
* @param pos the position to start from, negative treated as zero
* @param len the length of the required String
* @return the middle characters, {@code null} if null String input
*/
public static String mid(String str, int pos, int len) {
if (str == null) {
return null;
}
if (len < 0 || pos > str.length()) {
return EMPTY;
}
if (pos < 0) {
pos = 0;
}
if (str.length() <= (pos + len)) {
return str.substring(pos);
}
return str.substring(pos, pos + len);
}
// SubStringAfter/SubStringBefore
//-----------------------------------------------------------------------
/**
* <p>Gets the substring before the first occurrence of a separator.
* The separator is not returned.</p>
*
* <p>A {@code null} string input will return {@code null}.
* An empty ("") string input will return the empty string.
* A {@code null} separator will return the input string.</p>
*
* <p>If nothing is found, the string input is returned.</p>
*
* <pre>
* StringUtils.substringBefore(null, *) = null
* StringUtils.substringBefore("", *) = ""
* StringUtils.substringBefore("abc", "a") = ""
* StringUtils.substringBefore("abcba", "b") = "a"
* StringUtils.substringBefore("abc", "c") = "ab"
* StringUtils.substringBefore("abc", "d") = "abc"
* StringUtils.substringBefore("abc", "") = ""
* StringUtils.substringBefore("abc", null) = "abc"
* </pre>
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring before the first occurrence of the separator,
* {@code null} if null String input
* @since 2.0
*/
public static String substringBefore(String str, String separator) {
if (isEmpty(str) || separator == null) {
return str;
}
if (separator.length() == 0) {
return EMPTY;
}
int pos = str.indexOf(separator);
if (pos == INDEX_NOT_FOUND) {
return str;
}
return str.substring(0, pos);
}
/**
* <p>Gets the substring after the first occurrence of a separator.
* The separator is not returned.</p>
*
* <p>A {@code null} string input will return {@code null}.
* An empty ("") string input will return the empty string.
* A {@code null} separator will return the empty string if the
* input string is not {@code null}.</p>
*
* <p>If nothing is found, the empty string is returned.</p>
*
* <pre>
* StringUtils.substringAfter(null, *) = null
* StringUtils.substringAfter("", *) = ""
* StringUtils.substringAfter(*, null) = ""
* StringUtils.substringAfter("abc", "a") = "bc"
* StringUtils.substringAfter("abcba", "b") = "cba"
* StringUtils.substringAfter("abc", "c") = ""
* StringUtils.substringAfter("abc", "d") = ""
* StringUtils.substringAfter("abc", "") = "abc"
* </pre>
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring after the first occurrence of the separator,
* {@code null} if null String input
* @since 2.0
*/
public static String substringAfter(String str, String separator) {
if (isEmpty(str)) {
return str;
}
if (separator == null) {
return EMPTY;
}
int pos = str.indexOf(separator);
if (pos == INDEX_NOT_FOUND) {
return EMPTY;
}
return str.substring(pos + separator.length());
}
/**
* <p>Gets the substring before the last occurrence of a separator.
* The separator is not returned.</p>
*
* <p>A {@code null} string input will return {@code null}.
* An empty ("") string input will return the empty string.
* An empty or {@code null} separator will return the input string.</p>
*
* <p>If nothing is found, the string input is returned.</p>
*
* <pre>
* StringUtils.substringBeforeLast(null, *) = null
* StringUtils.substringBeforeLast("", *) = ""
* StringUtils.substringBeforeLast("abcba", "b") = "abc"
* StringUtils.substringBeforeLast("abc", "c") = "ab"
* StringUtils.substringBeforeLast("a", "a") = ""
* StringUtils.substringBeforeLast("a", "z") = "a"
* StringUtils.substringBeforeLast("a", null) = "a"
* StringUtils.substringBeforeLast("a", "") = "a"
* </pre>
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring before the last occurrence of the separator,
* {@code null} if null String input
* @since 2.0
*/
public static String substringBeforeLast(String str, String separator) {
if (isEmpty(str) || isEmpty(separator)) {
return str;
}
int pos = str.lastIndexOf(separator);
if (pos == INDEX_NOT_FOUND) {
return str;
}
return str.substring(0, pos);
}
/**
* <p>Gets the substring after the last occurrence of a separator.
* The separator is not returned.</p>
*
* <p>A {@code null} string input will return {@code null}.
* An empty ("") string input will return the empty string.
* An empty or {@code null} separator will return the empty string if
* the input string is not {@code null}.</p>
*
* <p>If nothing is found, the empty string is returned.</p>
*
* <pre>
* StringUtils.substringAfterLast(null, *) = null
* StringUtils.substringAfterLast("", *) = ""
* StringUtils.substringAfterLast(*, "") = ""
* StringUtils.substringAfterLast(*, null) = ""
* StringUtils.substringAfterLast("abc", "a") = "bc"
* StringUtils.substringAfterLast("abcba", "b") = "a"
* StringUtils.substringAfterLast("abc", "c") = ""
* StringUtils.substringAfterLast("a", "a") = ""
* StringUtils.substringAfterLast("a", "z") = ""
* </pre>
*
* @param str the String to get a substring from, may be null
* @param separator the String to search for, may be null
* @return the substring after the last occurrence of the separator,
* {@code null} if null String input
* @since 2.0
*/
public static String substringAfterLast(String str, String separator) {
if (isEmpty(str)) {
return str;
}
if (isEmpty(separator)) {
return EMPTY;
}
int pos = str.lastIndexOf(separator);
if (pos == INDEX_NOT_FOUND || pos == (str.length() - separator.length())) {
return EMPTY;
}
return str.substring(pos + separator.length());
}
// Substring between
//-----------------------------------------------------------------------
/**
* <p>Gets the String that is nested in between two instances of the
* same String.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} tag returns {@code null}.</p>
*
* <pre>
* StringUtils.substringBetween(null, *) = null
* StringUtils.substringBetween("", "") = ""
* StringUtils.substringBetween("", "tag") = null
* StringUtils.substringBetween("tagabctag", null) = null
* StringUtils.substringBetween("tagabctag", "") = ""
* StringUtils.substringBetween("tagabctag", "tag") = "abc"
* </pre>
*
* @param str the String containing the substring, may be null
* @param tag the String before and after the substring, may be null
* @return the substring, {@code null} if no match
* @since 2.0
*/
public static String substringBetween(String str, String tag) {
return substringBetween(str, tag, tag);
}
/**
* <p>Gets the String that is nested in between two Strings.
* Only the first match is returned.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} open/close returns {@code null} (no match).
* An empty ("") open and close returns an empty string.</p>
*
* <pre>
* StringUtils.substringBetween("wx[b]yz", "[", "]") = "b"
* StringUtils.substringBetween(null, *, *) = null
* StringUtils.substringBetween(*, null, *) = null
* StringUtils.substringBetween(*, *, null) = null
* StringUtils.substringBetween("", "", "") = ""
* StringUtils.substringBetween("", "", "]") = null
* StringUtils.substringBetween("", "[", "]") = null
* StringUtils.substringBetween("yabcz", "", "") = ""
* StringUtils.substringBetween("yabcz", "y", "z") = "abc"
* StringUtils.substringBetween("yabczyabcz", "y", "z") = "abc"
* </pre>
*
* @param str the String containing the substring, may be null
* @param open the String before the substring, may be null
* @param close the String after the substring, may be null
* @return the substring, {@code null} if no match
* @since 2.0
*/
public static String substringBetween(String str, String open, String close) {
if (str == null || open == null || close == null) {
return null;
}
int start = str.indexOf(open);
if (start != INDEX_NOT_FOUND) {
int end = str.indexOf(close, start + open.length());
if (end != INDEX_NOT_FOUND) {
return str.substring(start + open.length(), end);
}
}
return null;
}
/**
* <p>Searches a String for substrings delimited by a start and end tag,
* returning all matching substrings in an array.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} open/close returns {@code null} (no match).
* An empty ("") open/close returns {@code null} (no match).</p>
*
* <pre>
* StringUtils.substringsBetween("[a][b][c]", "[", "]") = ["a","b","c"]
* StringUtils.substringsBetween(null, *, *) = null
* StringUtils.substringsBetween(*, null, *) = null
* StringUtils.substringsBetween(*, *, null) = null
* StringUtils.substringsBetween("", "[", "]") = []
* </pre>
*
* @param str the String containing the substrings, null returns null, empty returns empty
* @param open the String identifying the start of the substring, empty returns null
* @param close the String identifying the end of the substring, empty returns null
* @return a String Array of substrings, or {@code null} if no match
* @since 2.3
*/
public static String[] substringsBetween(String str, String open, String close) {
if (str == null || isEmpty(open) || isEmpty(close)) {
return null;
}
int strLen = str.length();
if (strLen == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
int closeLen = close.length();
int openLen = open.length();
List<String> list = new ArrayList<String>();
int pos = 0;
while (pos < (strLen - closeLen)) {
int start = str.indexOf(open, pos);
if (start < 0) {
break;
}
start += openLen;
int end = str.indexOf(close, start);
if (end < 0) {
break;
}
list.add(str.substring(start, end));
pos = end + closeLen;
}
if (list.isEmpty()) {
return null;
}
return list.toArray(new String [list.size()]);
}
// Nested extraction
//-----------------------------------------------------------------------
// Splitting
//-----------------------------------------------------------------------
/**
* <p>Splits the provided text into an array, using whitespace as the
* separator.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.split(null) = null
* StringUtils.split("") = []
* StringUtils.split("abc def") = ["abc", "def"]
* StringUtils.split("abc def") = ["abc", "def"]
* StringUtils.split(" abc ") = ["abc"]
* </pre>
*
* @param str the String to parse, may be null
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(String str) {
return split(str, null, -1);
}
/**
* <p>Splits the provided text into an array, separator specified.
* This is an alternative to using StringTokenizer.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.split(null, *) = null
* StringUtils.split("", *) = []
* StringUtils.split("a.b.c", '.') = ["a", "b", "c"]
* StringUtils.split("a..b.c", '.') = ["a", "b", "c"]
* StringUtils.split("a:b:c", '.') = ["a:b:c"]
* StringUtils.split("a b c", ' ') = ["a", "b", "c"]
* </pre>
*
* @param str the String to parse, may be null
* @param separatorChar the character used as the delimiter
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.0
*/
public static String[] split(String str, char separatorChar) {
return splitWorker(str, separatorChar, false);
}
/**
* <p>Splits the provided text into an array, separators specified.
* This is an alternative to using StringTokenizer.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separatorChars splits on whitespace.</p>
*
* <pre>
* StringUtils.split(null, *) = null
* StringUtils.split("", *) = []
* StringUtils.split("abc def", null) = ["abc", "def"]
* StringUtils.split("abc def", " ") = ["abc", "def"]
* StringUtils.split("abc def", " ") = ["abc", "def"]
* StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
* </pre>
*
* @param str the String to parse, may be null
* @param separatorChars the characters used as the delimiters,
* {@code null} splits on whitespace
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(String str, String separatorChars) {
return splitWorker(str, separatorChars, -1, false);
}
/**
* <p>Splits the provided text into an array with a maximum length,
* separators specified.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separatorChars splits on whitespace.</p>
*
* <p>If more than {@code max} delimited substrings are found, the last
* returned string includes all characters after the first {@code max - 1}
* returned strings (including separator characters).</p>
*
* <pre>
* StringUtils.split(null, *, *) = null
* StringUtils.split("", *, *) = []
* StringUtils.split("ab de fg", null, 0) = ["ab", "cd", "ef"]
* StringUtils.split("ab de fg", null, 0) = ["ab", "cd", "ef"]
* StringUtils.split("ab:cd:ef", ":", 0) = ["ab", "cd", "ef"]
* StringUtils.split("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
* </pre>
*
* @param str the String to parse, may be null
* @param separatorChars the characters used as the delimiters,
* {@code null} splits on whitespace
* @param max the maximum number of elements to include in the
* array. A zero or negative value implies no limit
* @return an array of parsed Strings, {@code null} if null String input
*/
public static String[] split(String str, String separatorChars, int max) {
return splitWorker(str, separatorChars, max, false);
}
/**
* <p>Splits the provided text into an array, separator string specified.</p>
*
* <p>The separator(s) will not be included in the returned String array.
* Adjacent separators are treated as one separator.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separator splits on whitespace.</p>
*
* <pre>
* StringUtils.splitByWholeSeparator(null, *) = null
* StringUtils.splitByWholeSeparator("", *) = []
* StringUtils.splitByWholeSeparator("ab de fg", null) = ["ab", "de", "fg"]
* StringUtils.splitByWholeSeparator("ab de fg", null) = ["ab", "de", "fg"]
* StringUtils.splitByWholeSeparator("ab:cd:ef", ":") = ["ab", "cd", "ef"]
* StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
* </pre>
*
* @param str the String to parse, may be null
* @param separator String containing the String to be used as a delimiter,
* {@code null} splits on whitespace
* @return an array of parsed Strings, {@code null} if null String was input
*/
public static String[] splitByWholeSeparator(String str, String separator) {
return splitByWholeSeparatorWorker( str, separator, -1, false ) ;
}
/**
* <p>Splits the provided text into an array, separator string specified.
* Returns a maximum of {@code max} substrings.</p>
*
* <p>The separator(s) will not be included in the returned String array.
* Adjacent separators are treated as one separator.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separator splits on whitespace.</p>
*
* <pre>
* StringUtils.splitByWholeSeparator(null, *, *) = null
* StringUtils.splitByWholeSeparator("", *, *) = []
* StringUtils.splitByWholeSeparator("ab de fg", null, 0) = ["ab", "de", "fg"]
* StringUtils.splitByWholeSeparator("ab de fg", null, 0) = ["ab", "de", "fg"]
* StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
* StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
* StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
* </pre>
*
* @param str the String to parse, may be null
* @param separator String containing the String to be used as a delimiter,
* {@code null} splits on whitespace
* @param max the maximum number of elements to include in the returned
* array. A zero or negative value implies no limit.
* @return an array of parsed Strings, {@code null} if null String was input
*/
public static String[] splitByWholeSeparator( String str, String separator, int max ) {
return splitByWholeSeparatorWorker(str, separator, max, false);
}
/**
* <p>Splits the provided text into an array, separator string specified. </p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as separators for empty tokens.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separator splits on whitespace.</p>
*
* <pre>
* StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *) = null
* StringUtils.splitByWholeSeparatorPreserveAllTokens("", *) = []
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null) = ["ab", "de", "fg"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null) = ["ab", "", "", "de", "fg"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":") = ["ab", "cd", "ef"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
* </pre>
*
* @param str the String to parse, may be null
* @param separator String containing the String to be used as a delimiter,
* {@code null} splits on whitespace
* @return an array of parsed Strings, {@code null} if null String was input
* @since 2.4
*/
public static String[] splitByWholeSeparatorPreserveAllTokens(String str, String separator) {
return splitByWholeSeparatorWorker(str, separator, -1, true);
}
/**
* <p>Splits the provided text into an array, separator string specified.
* Returns a maximum of {@code max} substrings.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as separators for empty tokens.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separator splits on whitespace.</p>
*
* <pre>
* StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *, *) = null
* StringUtils.splitByWholeSeparatorPreserveAllTokens("", *, *) = []
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0) = ["ab", "de", "fg"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0) = ["ab", "", "", "de", "fg"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
* StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
* </pre>
*
* @param str the String to parse, may be null
* @param separator String containing the String to be used as a delimiter,
* {@code null} splits on whitespace
* @param max the maximum number of elements to include in the returned
* array. A zero or negative value implies no limit.
* @return an array of parsed Strings, {@code null} if null String was input
* @since 2.4
*/
public static String[] splitByWholeSeparatorPreserveAllTokens(String str, String separator, int max) {
return splitByWholeSeparatorWorker(str, separator, max, true);
}
/**
* Performs the logic for the {@code splitByWholeSeparatorPreserveAllTokens} methods.
*
* @param str the String to parse, may be {@code null}
* @param separator String containing the String to be used as a delimiter,
* {@code null} splits on whitespace
* @param max the maximum number of elements to include in the returned
* array. A zero or negative value implies no limit.
* @param preserveAllTokens if {@code true}, adjacent separators are
* treated as empty token separators; if {@code false}, adjacent
* separators are treated as one separator.
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.4
*/
private static String[] splitByWholeSeparatorWorker(
String str, String separator, int max, boolean preserveAllTokens) {
if (str == null) {
return null;
}
int len = str.length();
if (len == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
if ((separator == null) || (EMPTY.equals(separator))) {
// Split on whitespace.
return splitWorker(str, null, max, preserveAllTokens);
}
int separatorLength = separator.length();
ArrayList<String> substrings = new ArrayList<String>();
int numberOfSubstrings = 0;
int beg = 0;
int end = 0;
while (end < len) {
end = str.indexOf(separator, beg);
if (end > -1) {
if (end > beg) {
numberOfSubstrings += 1;
if (numberOfSubstrings == max) {
end = len;
substrings.add(str.substring(beg));
} else {
// The following is OK, because String.substring( beg, end ) excludes
// the character at the position 'end'.
substrings.add(str.substring(beg, end));
// Set the starting point for the next search.
// The following is equivalent to beg = end + (separatorLength - 1) + 1,
// which is the right calculation:
beg = end + separatorLength;
}
} else {
// We found a consecutive occurrence of the separator, so skip it.
if (preserveAllTokens) {
numberOfSubstrings += 1;
if (numberOfSubstrings == max) {
end = len;
substrings.add(str.substring(beg));
} else {
substrings.add(EMPTY);
}
}
beg = end + separatorLength;
}
} else {
// String.substring( beg ) goes from 'beg' to the end of the String.
substrings.add(str.substring(beg));
end = len;
}
}
return substrings.toArray(new String[substrings.size()]);
}
// -----------------------------------------------------------------------
/**
* <p>Splits the provided text into an array, using whitespace as the
* separator, preserving all tokens, including empty tokens created by
* adjacent separators. This is an alternative to using StringTokenizer.
* Whitespace is defined by {@link Character#isWhitespace(char)}.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as separators for empty tokens.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.splitPreserveAllTokens(null) = null
* StringUtils.splitPreserveAllTokens("") = []
* StringUtils.splitPreserveAllTokens("abc def") = ["abc", "def"]
* StringUtils.splitPreserveAllTokens("abc def") = ["abc", "", "def"]
* StringUtils.splitPreserveAllTokens(" abc ") = ["", "abc", ""]
* </pre>
*
* @param str the String to parse, may be {@code null}
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.1
*/
public static String[] splitPreserveAllTokens(String str) {
return splitWorker(str, null, -1, true);
}
/**
* <p>Splits the provided text into an array, separator specified,
* preserving all tokens, including empty tokens created by adjacent
* separators. This is an alternative to using StringTokenizer.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as separators for empty tokens.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.splitPreserveAllTokens(null, *) = null
* StringUtils.splitPreserveAllTokens("", *) = []
* StringUtils.splitPreserveAllTokens("a.b.c", '.') = ["a", "b", "c"]
* StringUtils.splitPreserveAllTokens("a..b.c", '.') = ["a", "", "b", "c"]
* StringUtils.splitPreserveAllTokens("a:b:c", '.') = ["a:b:c"]
* StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
* StringUtils.splitPreserveAllTokens("a b c", ' ') = ["a", "b", "c"]
* StringUtils.splitPreserveAllTokens("a b c ", ' ') = ["a", "b", "c", ""]
* StringUtils.splitPreserveAllTokens("a b c ", ' ') = ["a", "b", "c", "", ""]
* StringUtils.splitPreserveAllTokens(" a b c", ' ') = ["", a", "b", "c"]
* StringUtils.splitPreserveAllTokens(" a b c", ' ') = ["", "", a", "b", "c"]
* StringUtils.splitPreserveAllTokens(" a b c ", ' ') = ["", a", "b", "c", ""]
* </pre>
*
* @param str the String to parse, may be {@code null}
* @param separatorChar the character used as the delimiter,
* {@code null} splits on whitespace
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.1
*/
public static String[] splitPreserveAllTokens(String str, char separatorChar) {
return splitWorker(str, separatorChar, true);
}
/**
* Performs the logic for the {@code split} and
* {@code splitPreserveAllTokens} methods that do not return a
* maximum array length.
*
* @param str the String to parse, may be {@code null}
* @param separatorChar the separate character
* @param preserveAllTokens if {@code true}, adjacent separators are
* treated as empty token separators; if {@code false}, adjacent
* separators are treated as one separator.
* @return an array of parsed Strings, {@code null} if null String input
*/
private static String[] splitWorker(String str, char separatorChar, boolean preserveAllTokens) {
// Performance tuned for 2.0 (JDK1.4)
if (str == null) {
return null;
}
int len = str.length();
if (len == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
List<String> list = new ArrayList<String>();
int i = 0, start = 0;
boolean match = false;
boolean lastMatch = false;
while (i < len) {
if (str.charAt(i) == separatorChar) {
if (match || preserveAllTokens) {
list.add(str.substring(start, i));
match = false;
lastMatch = true;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
if (match || (preserveAllTokens && lastMatch)) {
list.add(str.substring(start, i));
}
return list.toArray(new String[list.size()]);
}
/**
* <p>Splits the provided text into an array, separators specified,
* preserving all tokens, including empty tokens created by adjacent
* separators. This is an alternative to using StringTokenizer.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as separators for empty tokens.
* For more control over the split use the StrTokenizer class.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separatorChars splits on whitespace.</p>
*
* <pre>
* StringUtils.splitPreserveAllTokens(null, *) = null
* StringUtils.splitPreserveAllTokens("", *) = []
* StringUtils.splitPreserveAllTokens("abc def", null) = ["abc", "def"]
* StringUtils.splitPreserveAllTokens("abc def", " ") = ["abc", "def"]
* StringUtils.splitPreserveAllTokens("abc def", " ") = ["abc", "", def"]
* StringUtils.splitPreserveAllTokens("ab:cd:ef", ":") = ["ab", "cd", "ef"]
* StringUtils.splitPreserveAllTokens("ab:cd:ef:", ":") = ["ab", "cd", "ef", ""]
* StringUtils.splitPreserveAllTokens("ab:cd:ef::", ":") = ["ab", "cd", "ef", "", ""]
* StringUtils.splitPreserveAllTokens("ab::cd:ef", ":") = ["ab", "", cd", "ef"]
* StringUtils.splitPreserveAllTokens(":cd:ef", ":") = ["", cd", "ef"]
* StringUtils.splitPreserveAllTokens("::cd:ef", ":") = ["", "", cd", "ef"]
* StringUtils.splitPreserveAllTokens(":cd:ef:", ":") = ["", cd", "ef", ""]
* </pre>
*
* @param str the String to parse, may be {@code null}
* @param separatorChars the characters used as the delimiters,
* {@code null} splits on whitespace
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.1
*/
public static String[] splitPreserveAllTokens(String str, String separatorChars) {
return splitWorker(str, separatorChars, -1, true);
}
/**
* <p>Splits the provided text into an array with a maximum length,
* separators specified, preserving all tokens, including empty tokens
* created by adjacent separators.</p>
*
* <p>The separator is not included in the returned String array.
* Adjacent separators are treated as separators for empty tokens.
* Adjacent separators are treated as one separator.</p>
*
* <p>A {@code null} input String returns {@code null}.
* A {@code null} separatorChars splits on whitespace.</p>
*
* <p>If more than {@code max} delimited substrings are found, the last
* returned string includes all characters after the first {@code max - 1}
* returned strings (including separator characters).</p>
*
* <pre>
* StringUtils.splitPreserveAllTokens(null, *, *) = null
* StringUtils.splitPreserveAllTokens("", *, *) = []
* StringUtils.splitPreserveAllTokens("ab de fg", null, 0) = ["ab", "cd", "ef"]
* StringUtils.splitPreserveAllTokens("ab de fg", null, 0) = ["ab", "cd", "ef"]
* StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 0) = ["ab", "cd", "ef"]
* StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
* StringUtils.splitPreserveAllTokens("ab de fg", null, 2) = ["ab", " de fg"]
* StringUtils.splitPreserveAllTokens("ab de fg", null, 3) = ["ab", "", " de fg"]
* StringUtils.splitPreserveAllTokens("ab de fg", null, 4) = ["ab", "", "", "de fg"]
* </pre>
*
* @param str the String to parse, may be {@code null}
* @param separatorChars the characters used as the delimiters,
* {@code null} splits on whitespace
* @param max the maximum number of elements to include in the
* array. A zero or negative value implies no limit
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.1
*/
public static String[] splitPreserveAllTokens(String str, String separatorChars, int max) {
return splitWorker(str, separatorChars, max, true);
}
/**
* Performs the logic for the {@code split} and
* {@code splitPreserveAllTokens} methods that return a maximum array
* length.
*
* @param str the String to parse, may be {@code null}
* @param separatorChars the separate character
* @param max the maximum number of elements to include in the
* array. A zero or negative value implies no limit.
* @param preserveAllTokens if {@code true}, adjacent separators are
* treated as empty token separators; if {@code false}, adjacent
* separators are treated as one separator.
* @return an array of parsed Strings, {@code null} if null String input
*/
private static String[] splitWorker(String str, String separatorChars, int max, boolean preserveAllTokens) {
// Performance tuned for 2.0 (JDK1.4)
// Direct code is quicker than StringTokenizer.
// Also, StringTokenizer uses isSpace() not isWhitespace()
if (str == null) {
return null;
}
int len = str.length();
if (len == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
List<String> list = new ArrayList<String>();
int sizePlus1 = 1;
int i = 0, start = 0;
boolean match = false;
boolean lastMatch = false;
if (separatorChars == null) {
// Null separator means use whitespace
while (i < len) {
if (Character.isWhitespace(str.charAt(i))) {
if (match || preserveAllTokens) {
lastMatch = true;
if (sizePlus1++ == max) {
i = len;
lastMatch = false;
}
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
} else if (separatorChars.length() == 1) {
// Optimise 1 character case
char sep = separatorChars.charAt(0);
while (i < len) {
if (str.charAt(i) == sep) {
if (match || preserveAllTokens) {
lastMatch = true;
if (sizePlus1++ == max) {
i = len;
lastMatch = false;
}
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
} else {
// standard case
while (i < len) {
if (separatorChars.indexOf(str.charAt(i)) >= 0) {
if (match || preserveAllTokens) {
lastMatch = true;
if (sizePlus1++ == max) {
i = len;
lastMatch = false;
}
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
lastMatch = false;
match = true;
i++;
}
}
if (match || (preserveAllTokens && lastMatch)) {
list.add(str.substring(start, i));
}
return list.toArray(new String[list.size()]);
}
/**
* <p>Splits a String by Character type as returned by
* {@code java.lang.Character.getType(char)}. Groups of contiguous
* characters of the same type are returned as complete tokens.
* <pre>
* StringUtils.splitByCharacterType(null) = null
* StringUtils.splitByCharacterType("") = []
* StringUtils.splitByCharacterType("ab de fg") = ["ab", " ", "de", " ", "fg"]
* StringUtils.splitByCharacterType("ab de fg") = ["ab", " ", "de", " ", "fg"]
* StringUtils.splitByCharacterType("ab:cd:ef") = ["ab", ":", "cd", ":", "ef"]
* StringUtils.splitByCharacterType("number5") = ["number", "5"]
* StringUtils.splitByCharacterType("fooBar") = ["foo", "B", "ar"]
* StringUtils.splitByCharacterType("foo200Bar") = ["foo", "200", "B", "ar"]
* StringUtils.splitByCharacterType("ASFRules") = ["ASFR", "ules"]
* </pre>
* @param str the String to split, may be {@code null}
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.4
*/
public static String[] splitByCharacterType(String str) {
return splitByCharacterType(str, false);
}
/**
* <p>Splits a String by Character type as returned by
* {@code java.lang.Character.getType(char)}. Groups of contiguous
* characters of the same type are returned as complete tokens, with the
* following exception: the character of type
* {@code Character.UPPERCASE_LETTER}, if any, immediately
* preceding a token of type {@code Character.LOWERCASE_LETTER}
* will belong to the following token rather than to the preceding, if any,
* {@code Character.UPPERCASE_LETTER} token.
* <pre>
* StringUtils.splitByCharacterTypeCamelCase(null) = null
* StringUtils.splitByCharacterTypeCamelCase("") = []
* StringUtils.splitByCharacterTypeCamelCase("ab de fg") = ["ab", " ", "de", " ", "fg"]
* StringUtils.splitByCharacterTypeCamelCase("ab de fg") = ["ab", " ", "de", " ", "fg"]
* StringUtils.splitByCharacterTypeCamelCase("ab:cd:ef") = ["ab", ":", "cd", ":", "ef"]
* StringUtils.splitByCharacterTypeCamelCase("number5") = ["number", "5"]
* StringUtils.splitByCharacterTypeCamelCase("fooBar") = ["foo", "Bar"]
* StringUtils.splitByCharacterTypeCamelCase("foo200Bar") = ["foo", "200", "Bar"]
* StringUtils.splitByCharacterTypeCamelCase("ASFRules") = ["ASF", "Rules"]
* </pre>
* @param str the String to split, may be {@code null}
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.4
*/
public static String[] splitByCharacterTypeCamelCase(String str) {
return splitByCharacterType(str, true);
}
/**
* <p>Splits a String by Character type as returned by
* {@code java.lang.Character.getType(char)}. Groups of contiguous
* characters of the same type are returned as complete tokens, with the
* following exception: if {@code camelCase} is {@code true},
* the character of type {@code Character.UPPERCASE_LETTER}, if any,
* immediately preceding a token of type {@code Character.LOWERCASE_LETTER}
* will belong to the following token rather than to the preceding, if any,
* {@code Character.UPPERCASE_LETTER} token.
* @param str the String to split, may be {@code null}
* @param camelCase whether to use so-called "camel-case" for letter types
* @return an array of parsed Strings, {@code null} if null String input
* @since 2.4
*/
private static String[] splitByCharacterType(String str, boolean camelCase) {
if (str == null) {
return null;
}
if (str.length() == 0) {
return ArrayUtils.EMPTY_STRING_ARRAY;
}
char[] c = str.toCharArray();
List<String> list = new ArrayList<String>();
int tokenStart = 0;
int currentType = Character.getType(c[tokenStart]);
for (int pos = tokenStart + 1; pos < c.length; pos++) {
int type = Character.getType(c[pos]);
if (type == currentType) {
continue;
}
if (camelCase && type == Character.LOWERCASE_LETTER && currentType == Character.UPPERCASE_LETTER) {
int newTokenStart = pos - 1;
if (newTokenStart != tokenStart) {
list.add(new String(c, tokenStart, newTokenStart - tokenStart));
tokenStart = newTokenStart;
}
} else {
list.add(new String(c, tokenStart, pos - tokenStart));
tokenStart = pos;
}
currentType = type;
}
list.add(new String(c, tokenStart, c.length - tokenStart));
return list.toArray(new String[list.size()]);
}
// Joining
//-----------------------------------------------------------------------
/**
* <p>Joins the elements of the provided array into a single String
* containing the provided list of elements.</p>
*
* <p>No separator is added to the joined String.
* Null objects or empty strings within the array are represented by
* empty strings.</p>
*
* <pre>
* StringUtils.join(null) = null
* StringUtils.join([]) = ""
* StringUtils.join([null]) = ""
* StringUtils.join(["a", "b", "c"]) = "abc"
* StringUtils.join([null, "", "a"]) = "a"
* </pre>
*
* @param <T> the specific type of values to join together
* @param elements the values to join together, may be null
* @return the joined String, {@code null} if null array input
* @since 2.0
* @since 3.0 Changed signature to use varargs
*/
public static <T> String join(T... elements) {
return join(elements, null);
}
/**
* <p>Joins the elements of the provided array into a single String
* containing the provided list of elements.</p>
*
* <p>No delimiter is added before or after the list.
* Null objects or empty strings within the array are represented by
* empty strings.</p>
*
* <pre>
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], ';') = "a;b;c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join([null, "", "a"], ';') = ";;a"
* </pre>
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use
* @return the joined String, {@code null} if null array input
* @since 2.0
*/
public static String join(Object[] array, char separator) {
if (array == null) {
return null;
}
return join(array, separator, 0, array.length);
}
/**
* <p>Joins the elements of the provided array into a single String
* containing the provided list of elements.</p>
*
* <p>No delimiter is added before or after the list.
* Null objects or empty strings within the array are represented by
* empty strings.</p>
*
* <pre>
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], ';') = "a;b;c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join([null, "", "a"], ';') = ";;a"
* </pre>
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use
* @param startIndex the first index to start joining from. It is
* an error to pass in an end index past the end of the array
* @param endIndex the index to stop joining from (exclusive). It is
* an error to pass in an end index past the end of the array
* @return the joined String, {@code null} if null array input
* @since 2.0
*/
public static String join(Object[] array, char separator, int startIndex, int endIndex) {
if (array == null) {
return null;
}
int noOfItems = (endIndex - startIndex);
if (noOfItems <= 0) {
return EMPTY;
}
StringBuilder buf = new StringBuilder(noOfItems * 16);
for (int i = startIndex; i < endIndex; i++) {
if (i > startIndex) {
buf.append(separator);
}
if (array[i] != null) {
buf.append(array[i]);
}
}
return buf.toString();
}
/**
* <p>Joins the elements of the provided array into a single String
* containing the provided list of elements.</p>
*
* <p>No delimiter is added before or after the list.
* A {@code null} separator is the same as an empty String ("").
* Null objects or empty strings within the array are represented by
* empty strings.</p>
*
* <pre>
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], "--") = "a--b--c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join(["a", "b", "c"], "") = "abc"
* StringUtils.join([null, "", "a"], ',') = ",,a"
* </pre>
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @return the joined String, {@code null} if null array input
*/
public static String join(Object[] array, String separator) {
if (array == null) {
return null;
}
return join(array, separator, 0, array.length);
}
/**
* <p>Joins the elements of the provided array into a single String
* containing the provided list of elements.</p>
*
* <p>No delimiter is added before or after the list.
* A {@code null} separator is the same as an empty String ("").
* Null objects or empty strings within the array are represented by
* empty strings.</p>
*
* <pre>
* StringUtils.join(null, *) = null
* StringUtils.join([], *) = ""
* StringUtils.join([null], *) = ""
* StringUtils.join(["a", "b", "c"], "--") = "a--b--c"
* StringUtils.join(["a", "b", "c"], null) = "abc"
* StringUtils.join(["a", "b", "c"], "") = "abc"
* StringUtils.join([null, "", "a"], ',') = ",,a"
* </pre>
*
* @param array the array of values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @param startIndex the first index to start joining from. It is
* an error to pass in an end index past the end of the array
* @param endIndex the index to stop joining from (exclusive). It is
* an error to pass in an end index past the end of the array
* @return the joined String, {@code null} if null array input
*/
public static String join(Object[] array, String separator, int startIndex, int endIndex) {
if (array == null) {
return null;
}
if (separator == null) {
separator = EMPTY;
}
// endIndex - startIndex > 0: Len = NofStrings *(len(firstString) + len(separator))
// (Assuming that all Strings are roughly equally long)
int noOfItems = (endIndex - startIndex);
if (noOfItems <= 0) {
return EMPTY;
}
StringBuilder buf = new StringBuilder(noOfItems * 16);
for (int i = startIndex; i < endIndex; i++) {
if (i > startIndex) {
buf.append(separator);
}
if (array[i] != null) {
buf.append(array[i]);
}
}
return buf.toString();
}
/**
* <p>Joins the elements of the provided {@code Iterator} into
* a single String containing the provided elements.</p>
*
* <p>No delimiter is added before or after the list. Null objects or empty
* strings within the iteration are represented by empty strings.</p>
*
* <p>See the examples here: {@link #join(Object[],char)}. </p>
*
* @param iterator the {@code Iterator} of values to join together, may be null
* @param separator the separator character to use
* @return the joined String, {@code null} if null iterator input
* @since 2.0
*/
public static String join(Iterator<?> iterator, char separator) {
// handle null, zero and one elements before building a buffer
if (iterator == null) {
return null;
}
if (!iterator.hasNext()) {
return EMPTY;
}
Object first = iterator.next();
if (!iterator.hasNext()) {
return ObjectUtils.toString(first);
}
// two or more elements
StringBuilder buf = new StringBuilder(256); // Java default is 16, probably too small
if (first != null) {
buf.append(first);
}
while (iterator.hasNext()) {
buf.append(separator);
Object obj = iterator.next();
if (obj != null) {
buf.append(obj);
}
}
return buf.toString();
}
/**
* <p>Joins the elements of the provided {@code Iterator} into
* a single String containing the provided elements.</p>
*
* <p>No delimiter is added before or after the list.
* A {@code null} separator is the same as an empty String ("").</p>
*
* <p>See the examples here: {@link #join(Object[],String)}. </p>
*
* @param iterator the {@code Iterator} of values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @return the joined String, {@code null} if null iterator input
*/
public static String join(Iterator<?> iterator, String separator) {
// handle null, zero and one elements before building a buffer
if (iterator == null) {
return null;
}
if (!iterator.hasNext()) {
return EMPTY;
}
Object first = iterator.next();
if (!iterator.hasNext()) {
return ObjectUtils.toString(first);
}
// two or more elements
StringBuilder buf = new StringBuilder(256); // Java default is 16, probably too small
if (first != null) {
buf.append(first);
}
while (iterator.hasNext()) {
if (separator != null) {
buf.append(separator);
}
Object obj = iterator.next();
if (obj != null) {
buf.append(obj);
}
}
return buf.toString();
}
/**
* <p>Joins the elements of the provided {@code Iterable} into
* a single String containing the provided elements.</p>
*
* <p>No delimiter is added before or after the list. Null objects or empty
* strings within the iteration are represented by empty strings.</p>
*
* <p>See the examples here: {@link #join(Object[],char)}. </p>
*
* @param iterable the {@code Iterable} providing the values to join together, may be null
* @param separator the separator character to use
* @return the joined String, {@code null} if null iterator input
* @since 2.3
*/
public static String join(Iterable<?> iterable, char separator) {
if (iterable == null) {
return null;
}
return join(iterable.iterator(), separator);
}
/**
* <p>Joins the elements of the provided {@code Iterable} into
* a single String containing the provided elements.</p>
*
* <p>No delimiter is added before or after the list.
* A {@code null} separator is the same as an empty String ("").</p>
*
* <p>See the examples here: {@link #join(Object[],String)}. </p>
*
* @param iterable the {@code Iterable} providing the values to join together, may be null
* @param separator the separator character to use, null treated as ""
* @return the joined String, {@code null} if null iterator input
* @since 2.3
*/
public static String join(Iterable<?> iterable, String separator) {
if (iterable == null) {
return null;
}
return join(iterable.iterator(), separator);
}
// Delete
//-----------------------------------------------------------------------
/**
* <p>Deletes all whitespaces from a String as defined by
* {@link Character#isWhitespace(char)}.</p>
*
* <pre>
* StringUtils.deleteWhitespace(null) = null
* StringUtils.deleteWhitespace("") = ""
* StringUtils.deleteWhitespace("abc") = "abc"
* StringUtils.deleteWhitespace(" ab c ") = "abc"
* </pre>
*
* @param str the String to delete whitespace from, may be null
* @return the String without whitespaces, {@code null} if null String input
*/
public static String deleteWhitespace(String str) {
if (isEmpty(str)) {
return str;
}
int sz = str.length();
char[] chs = new char[sz];
int count = 0;
for (int i = 0; i < sz; i++) {
if (!Character.isWhitespace(str.charAt(i))) {
chs[count++] = str.charAt(i);
}
}
if (count == sz) {
return str;
}
return new String(chs, 0, count);
}
// Remove
//-----------------------------------------------------------------------
/**
* <p>Removes a substring only if it is at the beginning of a source string,
* otherwise returns the source string.</p>
*
* <p>A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code null} search string will return the source string.</p>
*
* <pre>
* StringUtils.removeStart(null, *) = null
* StringUtils.removeStart("", *) = ""
* StringUtils.removeStart(*, null) = *
* StringUtils.removeStart("www.domain.com", "www.") = "domain.com"
* StringUtils.removeStart("domain.com", "www.") = "domain.com"
* StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
* StringUtils.removeStart("abc", "") = "abc"
* </pre>
*
* @param str the source String to search, may be null
* @param remove the String to search for and remove, may be null
* @return the substring with the string removed if found,
* {@code null} if null String input
* @since 2.1
*/
public static String removeStart(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.startsWith(remove)){
return str.substring(remove.length());
}
return str;
}
/**
* <p>Case insensitive removal of a substring if it is at the beginning of a source string,
* otherwise returns the source string.</p>
*
* <p>A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code null} search string will return the source string.</p>
*
* <pre>
* StringUtils.removeStartIgnoreCase(null, *) = null
* StringUtils.removeStartIgnoreCase("", *) = ""
* StringUtils.removeStartIgnoreCase(*, null) = *
* StringUtils.removeStartIgnoreCase("www.domain.com", "www.") = "domain.com"
* StringUtils.removeStartIgnoreCase("www.domain.com", "WWW.") = "domain.com"
* StringUtils.removeStartIgnoreCase("domain.com", "www.") = "domain.com"
* StringUtils.removeStartIgnoreCase("www.domain.com", "domain") = "www.domain.com"
* StringUtils.removeStartIgnoreCase("abc", "") = "abc"
* </pre>
*
* @param str the source String to search, may be null
* @param remove the String to search for (case insensitive) and remove, may be null
* @return the substring with the string removed if found,
* {@code null} if null String input
* @since 2.4
*/
public static String removeStartIgnoreCase(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (startsWithIgnoreCase(str, remove)) {
return str.substring(remove.length());
}
return str;
}
/**
* <p>Removes a substring only if it is at the end of a source string,
* otherwise returns the source string.</p>
*
* <p>A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code null} search string will return the source string.</p>
*
* <pre>
* StringUtils.removeEnd(null, *) = null
* StringUtils.removeEnd("", *) = ""
* StringUtils.removeEnd(*, null) = *
* StringUtils.removeEnd("www.domain.com", ".com.") = "www.domain.com"
* StringUtils.removeEnd("www.domain.com", ".com") = "www.domain"
* StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
* StringUtils.removeEnd("abc", "") = "abc"
* </pre>
*
* @param str the source String to search, may be null
* @param remove the String to search for and remove, may be null
* @return the substring with the string removed if found,
* {@code null} if null String input
* @since 2.1
*/
public static String removeEnd(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (str.endsWith(remove)) {
return str.substring(0, str.length() - remove.length());
}
return str;
}
/**
* <p>Case insensitive removal of a substring if it is at the end of a source string,
* otherwise returns the source string.</p>
*
* <p>A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code null} search string will return the source string.</p>
*
* <pre>
* StringUtils.removeEndIgnoreCase(null, *) = null
* StringUtils.removeEndIgnoreCase("", *) = ""
* StringUtils.removeEndIgnoreCase(*, null) = *
* StringUtils.removeEndIgnoreCase("www.domain.com", ".com.") = "www.domain.com"
* StringUtils.removeEndIgnoreCase("www.domain.com", ".com") = "www.domain"
* StringUtils.removeEndIgnoreCase("www.domain.com", "domain") = "www.domain.com"
* StringUtils.removeEndIgnoreCase("abc", "") = "abc"
* StringUtils.removeEndIgnoreCase("www.domain.com", ".COM") = "www.domain")
* StringUtils.removeEndIgnoreCase("www.domain.COM", ".com") = "www.domain")
* </pre>
*
* @param str the source String to search, may be null
* @param remove the String to search for (case insensitive) and remove, may be null
* @return the substring with the string removed if found,
* {@code null} if null String input
* @since 2.4
*/
public static String removeEndIgnoreCase(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
if (endsWithIgnoreCase(str, remove)) {
return str.substring(0, str.length() - remove.length());
}
return str;
}
/**
* <p>Removes all occurrences of a substring from within the source string.</p>
*
* <p>A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.
* A {@code null} remove string will return the source string.
* An empty ("") remove string will return the source string.</p>
*
* <pre>
* StringUtils.remove(null, *) = null
* StringUtils.remove("", *) = ""
* StringUtils.remove(*, null) = *
* StringUtils.remove(*, "") = *
* StringUtils.remove("queued", "ue") = "qd"
* StringUtils.remove("queued", "zz") = "queued"
* </pre>
*
* @param str the source String to search, may be null
* @param remove the String to search for and remove, may be null
* @return the substring with the string removed if found,
* {@code null} if null String input
* @since 2.1
*/
public static String remove(String str, String remove) {
if (isEmpty(str) || isEmpty(remove)) {
return str;
}
return replace(str, remove, EMPTY, -1);
}
/**
* <p>Removes all occurrences of a character from within the source string.</p>
*
* <p>A {@code null} source string will return {@code null}.
* An empty ("") source string will return the empty string.</p>
*
* <pre>
* StringUtils.remove(null, *) = null
* StringUtils.remove("", *) = ""
* StringUtils.remove("queued", 'u') = "qeed"
* StringUtils.remove("queued", 'z') = "queued"
* </pre>
*
* @param str the source String to search, may be null
* @param remove the char to search for and remove, may be null
* @return the substring with the char removed if found,
* {@code null} if null String input
* @since 2.1
*/
public static String remove(String str, char remove) {
if (isEmpty(str) || str.indexOf(remove) == INDEX_NOT_FOUND) {
return str;
}
char[] chars = str.toCharArray();
int pos = 0;
for (int i = 0; i < chars.length; i++) {
if (chars[i] != remove) {
chars[pos++] = chars[i];
}
}
return new String(chars, 0, pos);
}
// Replacing
//-----------------------------------------------------------------------
/**
* <p>Replaces a String with another String inside a larger String, once.</p>
*
* <p>A {@code null} reference passed to this method is a no-op.</p>
*
* <pre>
* StringUtils.replaceOnce(null, *, *) = null
* StringUtils.replaceOnce("", *, *) = ""
* StringUtils.replaceOnce("any", null, *) = "any"
* StringUtils.replaceOnce("any", *, null) = "any"
* StringUtils.replaceOnce("any", "", *) = "any"
* StringUtils.replaceOnce("aba", "a", null) = "aba"
* StringUtils.replaceOnce("aba", "a", "") = "ba"
* StringUtils.replaceOnce("aba", "a", "z") = "zba"
* </pre>
*
* @see #replace(String text, String searchString, String replacement, int max)
* @param text text to search and replace in, may be null
* @param searchString the String to search for, may be null
* @param replacement the String to replace with, may be null
* @return the text with any replacements processed,
* {@code null} if null String input
*/
public static String replaceOnce(String text, String searchString, String replacement) {
return replace(text, searchString, replacement, 1);
}
/**
* <p>Replaces all occurrences of a String within another String.</p>
*
* <p>A {@code null} reference passed to this method is a no-op.</p>
*
* <pre>
* StringUtils.replace(null, *, *) = null
* StringUtils.replace("", *, *) = ""
* StringUtils.replace("any", null, *) = "any"
* StringUtils.replace("any", *, null) = "any"
* StringUtils.replace("any", "", *) = "any"
* StringUtils.replace("aba", "a", null) = "aba"
* StringUtils.replace("aba", "a", "") = "b"
* StringUtils.replace("aba", "a", "z") = "zbz"
* </pre>
*
* @see #replace(String text, String searchString, String replacement, int max)
* @param text text to search and replace in, may be null
* @param searchString the String to search for, may be null
* @param replacement the String to replace it with, may be null
* @return the text with any replacements processed,
* {@code null} if null String input
*/
public static String replace(String text, String searchString, String replacement) {
return replace(text, searchString, replacement, -1);
}
/**
* <p>Replaces a String with another String inside a larger String,
* for the first {@code max} values of the search String.</p>
*
* <p>A {@code null} reference passed to this method is a no-op.</p>
*
* <pre>
* StringUtils.replace(null, *, *, *) = null
* StringUtils.replace("", *, *, *) = ""
* StringUtils.replace("any", null, *, *) = "any"
* StringUtils.replace("any", *, null, *) = "any"
* StringUtils.replace("any", "", *, *) = "any"
* StringUtils.replace("any", *, *, 0) = "any"
* StringUtils.replace("abaa", "a", null, -1) = "abaa"
* StringUtils.replace("abaa", "a", "", -1) = "b"
* StringUtils.replace("abaa", "a", "z", 0) = "abaa"
* StringUtils.replace("abaa", "a", "z", 1) = "zbaa"
* StringUtils.replace("abaa", "a", "z", 2) = "zbza"
* StringUtils.replace("abaa", "a", "z", -1) = "zbzz"
* </pre>
*
* @param text text to search and replace in, may be null
* @param searchString the String to search for, may be null
* @param replacement the String to replace it with, may be null
* @param max maximum number of values to replace, or {@code -1} if no maximum
* @return the text with any replacements processed,
* {@code null} if null String input
*/
public static String replace(String text, String searchString, String replacement, int max) {
if (isEmpty(text) || isEmpty(searchString) || replacement == null || max == 0) {
return text;
}
int start = 0;
int end = text.indexOf(searchString, start);
if (end == INDEX_NOT_FOUND) {
return text;
}
int replLength = searchString.length();
int increase = replacement.length() - replLength;
increase = (increase < 0 ? 0 : increase);
increase *= (max < 0 ? 16 : (max > 64 ? 64 : max));
StringBuilder buf = new StringBuilder(text.length() + increase);
while (end != INDEX_NOT_FOUND) {
buf.append(text.substring(start, end)).append(replacement);
start = end + replLength;
if (--max == 0) {
break;
}
end = text.indexOf(searchString, start);
}
buf.append(text.substring(start));
return buf.toString();
}
/**
* <p>
* Replaces all occurrences of Strings within another String.
* </p>
*
* <p>
* A {@code null} reference passed to this method is a no-op, or if
* any "search string" or "string to replace" is null, that replace will be
* ignored. This will not repeat. For repeating replaces, call the
* overloaded method.
* </p>
*
* <pre>
* StringUtils.replaceEach(null, *, *) = null
* StringUtils.replaceEach("", *, *) = ""
* StringUtils.replaceEach("aba", null, null) = "aba"
* StringUtils.replaceEach("aba", new String[0], null) = "aba"
* StringUtils.replaceEach("aba", null, new String[0]) = "aba"
* StringUtils.replaceEach("aba", new String[]{"a"}, null) = "aba"
* StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}) = "b"
* StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}) = "aba"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}) = "wcte"
* (example of how it does not repeat)
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}) = "dcte"
* </pre>
*
* @param text
* text to search and replace in, no-op if null
* @param searchList
* the Strings to search for, no-op if null
* @param replacementList
* the Strings to replace them with, no-op if null
* @return the text with any replacements processed, {@code null} if
* null String input
* @throws IllegalArgumentException
* if the lengths of the arrays are not the same (null is ok,
* and/or size 0)
* @since 2.4
*/
public static String replaceEach(String text, String[] searchList, String[] replacementList) {
return replaceEach(text, searchList, replacementList, false, 0);
}
/**
* <p>
* Replaces all occurrences of Strings within another String.
* </p>
*
* <p>
* A {@code null} reference passed to this method is a no-op, or if
* any "search string" or "string to replace" is null, that replace will be
* ignored.
* </p>
*
* <pre>
* StringUtils.replaceEach(null, *, *, *) = null
* StringUtils.replaceEach("", *, *, *) = ""
* StringUtils.replaceEach("aba", null, null, *) = "aba"
* StringUtils.replaceEach("aba", new String[0], null, *) = "aba"
* StringUtils.replaceEach("aba", null, new String[0], *) = "aba"
* StringUtils.replaceEach("aba", new String[]{"a"}, null, *) = "aba"
* StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}, *) = "b"
* StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}, *) = "aba"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}, *) = "wcte"
* (example of how it repeats)
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, false) = "dcte"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, true) = "tcte"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, true) = IllegalStateException
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, false) = "dcabe"
* </pre>
*
* @param text
* text to search and replace in, no-op if null
* @param searchList
* the Strings to search for, no-op if null
* @param replacementList
* the Strings to replace them with, no-op if null
* @return the text with any replacements processed, {@code null} if
* null String input
* @throws IllegalStateException
* if the search is repeating and there is an endless loop due
* to outputs of one being inputs to another
* @throws IllegalArgumentException
* if the lengths of the arrays are not the same (null is ok,
* and/or size 0)
* @since 2.4
*/
public static String replaceEachRepeatedly(String text, String[] searchList, String[] replacementList) {
// timeToLive should be 0 if not used or nothing to replace, else it's
// the length of the replace array
int timeToLive = searchList == null ? 0 : searchList.length;
return replaceEach(text, searchList, replacementList, true, timeToLive);
}
/**
* <p>
* Replaces all occurrences of Strings within another String.
* </p>
*
* <p>
* A {@code null} reference passed to this method is a no-op, or if
* any "search string" or "string to replace" is null, that replace will be
* ignored.
* </p>
*
* <pre>
* StringUtils.replaceEach(null, *, *, *) = null
* StringUtils.replaceEach("", *, *, *) = ""
* StringUtils.replaceEach("aba", null, null, *) = "aba"
* StringUtils.replaceEach("aba", new String[0], null, *) = "aba"
* StringUtils.replaceEach("aba", null, new String[0], *) = "aba"
* StringUtils.replaceEach("aba", new String[]{"a"}, null, *) = "aba"
* StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}, *) = "b"
* StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}, *) = "aba"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}, *) = "wcte"
* (example of how it repeats)
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, false) = "dcte"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, true) = "tcte"
* StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, *) = IllegalStateException
* </pre>
*
* @param text
* text to search and replace in, no-op if null
* @param searchList
* the Strings to search for, no-op if null
* @param replacementList
* the Strings to replace them with, no-op if null
* @param repeat if true, then replace repeatedly
* until there are no more possible replacements or timeToLive < 0
* @param timeToLive
* if less than 0 then there is a circular reference and endless
* loop
* @return the text with any replacements processed, {@code null} if
* null String input
* @throws IllegalStateException
* if the search is repeating and there is an endless loop due
* to outputs of one being inputs to another
* @throws IllegalArgumentException
* if the lengths of the arrays are not the same (null is ok,
* and/or size 0)
* @since 2.4
*/
private static String replaceEach(
String text, String[] searchList, String[] replacementList, boolean repeat, int timeToLive) {
// mchyzer Performance note: This creates very few new objects (one major goal)
// let me know if there are performance requests, we can create a harness to measure
if (text == null || text.length() == 0 || searchList == null ||
searchList.length == 0 || replacementList == null || replacementList.length == 0) {
return text;
}
// if recursing, this shouldn't be less than 0
if (timeToLive < 0) {
throw new IllegalStateException("Aborting to protect against StackOverflowError - " +
"output of one loop is the input of another");
}
int searchLength = searchList.length;
int replacementLength = replacementList.length;
// make sure lengths are ok, these need to be equal
if (searchLength != replacementLength) {
throw new IllegalArgumentException("Search and Replace array lengths don't match: "
+ searchLength
+ " vs "
+ replacementLength);
}
// keep track of which still have matches
boolean[] noMoreMatchesForReplIndex = new boolean[searchLength];
// index on index that the match was found
int textIndex = -1;
int replaceIndex = -1;
int tempIndex = -1;
// index of replace array that will replace the search string found
// NOTE: logic duplicated below START
for (int i = 0; i < searchLength; i++) {
if (noMoreMatchesForReplIndex[i] || searchList[i] == null ||
searchList[i].length() == 0 || replacementList[i] == null) {
continue;
}
tempIndex = text.indexOf(searchList[i]);
// see if we need to keep searching for this
if (tempIndex == -1) {
noMoreMatchesForReplIndex[i] = true;
} else {
if (textIndex == -1 || tempIndex < textIndex) {
textIndex = tempIndex;
replaceIndex = i;
}
}
}
// NOTE: logic mostly below END
// no search strings found, we are done
if (textIndex == -1) {
return text;
}
int start = 0;
// get a good guess on the size of the result buffer so it doesn't have to double if it goes over a bit
int increase = 0;
// count the replacement text elements that are larger than their corresponding text being replaced
for (int i = 0; i < searchList.length; i++) {
if (searchList[i] == null || replacementList[i] == null) {
continue;
}
int greater = replacementList[i].length() - searchList[i].length();
if (greater > 0) {
increase += 3 * greater; // assume 3 matches
}
}
// have upper-bound at 20% increase, then let Java take over
increase = Math.min(increase, text.length() / 5);
StringBuilder buf = new StringBuilder(text.length() + increase);
while (textIndex != -1) {
for (int i = start; i < textIndex; i++) {
buf.append(text.charAt(i));
}
buf.append(replacementList[replaceIndex]);
start = textIndex + searchList[replaceIndex].length();
textIndex = -1;
replaceIndex = -1;
tempIndex = -1;
// find the next earliest match
// NOTE: logic mostly duplicated above START
for (int i = 0; i < searchLength; i++) {
if (noMoreMatchesForReplIndex[i] || searchList[i] == null ||
searchList[i].length() == 0 || replacementList[i] == null) {
continue;
}
tempIndex = text.indexOf(searchList[i], start);
// see if we need to keep searching for this
if (tempIndex == -1) {
noMoreMatchesForReplIndex[i] = true;
} else {
if (textIndex == -1 || tempIndex < textIndex) {
textIndex = tempIndex;
replaceIndex = i;
}
}
}
// NOTE: logic duplicated above END
}
int textLength = text.length();
for (int i = start; i < textLength; i++) {
buf.append(text.charAt(i));
}
String result = buf.toString();
if (!repeat) {
return result;
}
return replaceEach(result, searchList, replacementList, repeat, timeToLive - 1);
}
// Replace, character based
//-----------------------------------------------------------------------
/**
* <p>Replaces all occurrences of a character in a String with another.
* This is a null-safe version of {@link String#replace(char, char)}.</p>
*
* <p>A {@code null} string input returns {@code null}.
* An empty ("") string input returns an empty string.</p>
*
* <pre>
* StringUtils.replaceChars(null, *, *) = null
* StringUtils.replaceChars("", *, *) = ""
* StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
* StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
* </pre>
*
* @param str String to replace characters in, may be null
* @param searchChar the character to search for, may be null
* @param replaceChar the character to replace, may be null
* @return modified String, {@code null} if null string input
* @since 2.0
*/
public static String replaceChars(String str, char searchChar, char replaceChar) {
if (str == null) {
return null;
}
return str.replace(searchChar, replaceChar);
}
/**
* <p>Replaces multiple characters in a String in one go.
* This method can also be used to delete characters.</p>
*
* <p>For example:<br />
* <code>replaceChars("hello", "ho", "jy") = jelly</code>.</p>
*
* <p>A {@code null} string input returns {@code null}.
* An empty ("") string input returns an empty string.
* A null or empty set of search characters returns the input string.</p>
*
* <p>The length of the search characters should normally equal the length
* of the replace characters.
* If the search characters is longer, then the extra search characters
* are deleted.
* If the search characters is shorter, then the extra replace characters
* are ignored.</p>
*
* <pre>
* StringUtils.replaceChars(null, *, *) = null
* StringUtils.replaceChars("", *, *) = ""
* StringUtils.replaceChars("abc", null, *) = "abc"
* StringUtils.replaceChars("abc", "", *) = "abc"
* StringUtils.replaceChars("abc", "b", null) = "ac"
* StringUtils.replaceChars("abc", "b", "") = "ac"
* StringUtils.replaceChars("abcba", "bc", "yz") = "ayzya"
* StringUtils.replaceChars("abcba", "bc", "y") = "ayya"
* StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
* </pre>
*
* @param str String to replace characters in, may be null
* @param searchChars a set of characters to search for, may be null
* @param replaceChars a set of characters to replace, may be null
* @return modified String, {@code null} if null string input
* @since 2.0
*/
public static String replaceChars(String str, String searchChars, String replaceChars) {
if (isEmpty(str) || isEmpty(searchChars)) {
return str;
}
if (replaceChars == null) {
replaceChars = EMPTY;
}
boolean modified = false;
int replaceCharsLength = replaceChars.length();
int strLength = str.length();
StringBuilder buf = new StringBuilder(strLength);
for (int i = 0; i < strLength; i++) {
char ch = str.charAt(i);
int index = searchChars.indexOf(ch);
if (index >= 0) {
modified = true;
if (index < replaceCharsLength) {
buf.append(replaceChars.charAt(index));
}
} else {
buf.append(ch);
}
}
if (modified) {
return buf.toString();
}
return str;
}
// Overlay
//-----------------------------------------------------------------------
/**
* <p>Overlays part of a String with another String.</p>
*
* <p>A {@code null} string input returns {@code null}.
* A negative index is treated as zero.
* An index greater than the string length is treated as the string length.
* The start index is always the smaller of the two indices.</p>
*
* <pre>
* StringUtils.overlay(null, *, *, *) = null
* StringUtils.overlay("", "abc", 0, 0) = "abc"
* StringUtils.overlay("abcdef", null, 2, 4) = "abef"
* StringUtils.overlay("abcdef", "", 2, 4) = "abef"
* StringUtils.overlay("abcdef", "", 4, 2) = "abef"
* StringUtils.overlay("abcdef", "zzzz", 2, 4) = "abzzzzef"
* StringUtils.overlay("abcdef", "zzzz", 4, 2) = "abzzzzef"
* StringUtils.overlay("abcdef", "zzzz", -1, 4) = "zzzzef"
* StringUtils.overlay("abcdef", "zzzz", 2, 8) = "abzzzz"
* StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
* StringUtils.overlay("abcdef", "zzzz", 8, 10) = "abcdefzzzz"
* </pre>
*
* @param str the String to do overlaying in, may be null
* @param overlay the String to overlay, may be null
* @param start the position to start overlaying at
* @param end the position to stop overlaying before
* @return overlayed String, {@code null} if null String input
* @since 2.0
*/
public static String overlay(String str, String overlay, int start, int end) {
if (str == null) {
return null;
}
if (overlay == null) {
overlay = EMPTY;
}
int len = str.length();
if (start < 0) {
start = 0;
}
if (start > len) {
start = len;
}
if (end < 0) {
end = 0;
}
if (end > len) {
end = len;
}
if (start > end) {
int temp = start;
start = end;
end = temp;
}
return new StringBuilder(len + start - end + overlay.length() + 1)
.append(str.substring(0, start))
.append(overlay)
.append(str.substring(end))
.toString();
}
// Chomping
//-----------------------------------------------------------------------
/**
* <p>Removes one newline from end of a String if it's there,
* otherwise leave it alone. A newline is "{@code \n}",
* "{@code \r}", or "{@code \r\n}".</p>
*
* <p>NOTE: This method changed in 2.0.
* It now more closely matches Perl chomp.</p>
*
* <pre>
* StringUtils.chomp(null) = null
* StringUtils.chomp("") = ""
* StringUtils.chomp("abc \r") = "abc "
* StringUtils.chomp("abc\n") = "abc"
* StringUtils.chomp("abc\r\n") = "abc"
* StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
* StringUtils.chomp("abc\n\r") = "abc\n"
* StringUtils.chomp("abc\n\rabc") = "abc\n\rabc"
* StringUtils.chomp("\r") = ""
* StringUtils.chomp("\n") = ""
* StringUtils.chomp("\r\n") = ""
* </pre>
*
* @param str the String to chomp a newline from, may be null
* @return String without newline, {@code null} if null String input
*/
public static String chomp(String str) {
if (isEmpty(str)) {
return str;
}
if (str.length() == 1) {
char ch = str.charAt(0);
if (ch == CharUtils.CR || ch == CharUtils.LF) {
return EMPTY;
}
return str;
}
int lastIdx = str.length() - 1;
char last = str.charAt(lastIdx);
if (last == CharUtils.LF) {
if (str.charAt(lastIdx - 1) == CharUtils.CR) {
lastIdx--;
}
} else if (last != CharUtils.CR) {
lastIdx++;
}
return str.substring(0, lastIdx);
}
/**
* <p>Removes {@code separator} from the end of
* {@code str} if it's there, otherwise leave it alone.</p>
*
* <p>NOTE: This method changed in version 2.0.
* It now more closely matches Perl chomp.
* For the previous behavior, use {@link #substringBeforeLast(String, String)}.
* This method uses {@link String#endsWith(String)}.</p>
*
* <pre>
* StringUtils.chomp(null, *) = null
* StringUtils.chomp("", *) = ""
* StringUtils.chomp("foobar", "bar") = "foo"
* StringUtils.chomp("foobar", "baz") = "foobar"
* StringUtils.chomp("foo", "foo") = ""
* StringUtils.chomp("foo ", "foo") = "foo "
* StringUtils.chomp(" foo", "foo") = " "
* StringUtils.chomp("foo", "foooo") = "foo"
* StringUtils.chomp("foo", "") = "foo"
* StringUtils.chomp("foo", null) = "foo"
* </pre>
*
* @param str the String to chomp from, may be null
* @param separator separator String, may be null
* @return String without trailing separator, {@code null} if null String input
*/
public static String chomp(String str, String separator) {
if (isEmpty(str) || separator == null) {
return str;
}
if (str.endsWith(separator)) {
return str.substring(0, str.length() - separator.length());
}
return str;
}
// Chopping
//-----------------------------------------------------------------------
/**
* <p>Remove the last character from a String.</p>
*
* <p>If the String ends in {@code \r\n}, then remove both
* of them.</p>
*
* <pre>
* StringUtils.chop(null) = null
* StringUtils.chop("") = ""
* StringUtils.chop("abc \r") = "abc "
* StringUtils.chop("abc\n") = "abc"
* StringUtils.chop("abc\r\n") = "abc"
* StringUtils.chop("abc") = "ab"
* StringUtils.chop("abc\nabc") = "abc\nab"
* StringUtils.chop("a") = ""
* StringUtils.chop("\r") = ""
* StringUtils.chop("\n") = ""
* StringUtils.chop("\r\n") = ""
* </pre>
*
* @param str the String to chop last character from, may be null
* @return String without last character, {@code null} if null String input
*/
public static String chop(String str) {
if (str == null) {
return null;
}
int strLen = str.length();
if (strLen < 2) {
return EMPTY;
}
int lastIdx = strLen - 1;
String ret = str.substring(0, lastIdx);
char last = str.charAt(lastIdx);
if (last == CharUtils.LF && ret.charAt(lastIdx - 1) == CharUtils.CR) {
return ret.substring(0, lastIdx - 1);
}
return ret;
}
// Conversion
//-----------------------------------------------------------------------
// Padding
//-----------------------------------------------------------------------
/**
* <p>Repeat a String {@code repeat} times to form a
* new String.</p>
*
* <pre>
* StringUtils.repeat(null, 2) = null
* StringUtils.repeat("", 0) = ""
* StringUtils.repeat("", 2) = ""
* StringUtils.repeat("a", 3) = "aaa"
* StringUtils.repeat("ab", 2) = "abab"
* StringUtils.repeat("a", -2) = ""
* </pre>
*
* @param str the String to repeat, may be null
* @param repeat number of times to repeat str, negative treated as zero
* @return a new String consisting of the original String repeated,
* {@code null} if null String input
*/
public static String repeat(String str, int repeat) {
// Performance tuned for 2.0 (JDK1.4)
if (str == null) {
return null;
}
if (repeat <= 0) {
return EMPTY;
}
int inputLength = str.length();
if (repeat == 1 || inputLength == 0) {
return str;
}
if (inputLength == 1 && repeat <= PAD_LIMIT) {
return repeat(str.charAt(0), repeat);
}
int outputLength = inputLength * repeat;
switch (inputLength) {
case 1 :
return repeat(str.charAt(0), repeat);
case 2 :
char ch0 = str.charAt(0);
char ch1 = str.charAt(1);
char[] output2 = new char[outputLength];
for (int i = repeat * 2 - 2; i >= 0; i--, i--) {
output2[i] = ch0;
output2[i + 1] = ch1;
}
return new String(output2);
default :
StringBuilder buf = new StringBuilder(outputLength);
for (int i = 0; i < repeat; i++) {
buf.append(str);
}
return buf.toString();
}
}
/**
* <p>Repeat a String {@code repeat} times to form a
* new String, with a String separator injected each time. </p>
*
* <pre>
* StringUtils.repeat(null, null, 2) = null
* StringUtils.repeat(null, "x", 2) = null
* StringUtils.repeat("", null, 0) = ""
* StringUtils.repeat("", "", 2) = ""
* StringUtils.repeat("", "x", 3) = "xxx"
* StringUtils.repeat("?", ", ", 3) = "?, ?, ?"
* </pre>
*
* @param str the String to repeat, may be null
* @param separator the String to inject, may be null
* @param repeat number of times to repeat str, negative treated as zero
* @return a new String consisting of the original String repeated,
* {@code null} if null String input
* @since 2.5
*/
public static String repeat(String str, String separator, int repeat) {
if(str == null || separator == null) {
return repeat(str, repeat);
} else {
// given that repeat(String, int) is quite optimized, better to rely on it than try and splice this into it
String result = repeat(str + separator, repeat);
return removeEnd(result, separator);
}
}
/**
* <p>Returns padding using the specified delimiter repeated
* to a given length.</p>
*
* <pre>
* StringUtils.repeat(0, 'e') = ""
* StringUtils.repeat(3, 'e') = "eee"
* StringUtils.repeat(-2, 'e') = ""
* </pre>
*
* <p>Note: this method doesn't not support padding with
* <a href="http://www.unicode.org/glossary/#supplementary_character">Unicode Supplementary Characters</a>
* as they require a pair of {@code char}s to be represented.
* If you are needing to support full I18N of your applications
* consider using {@link #repeat(String, int)} instead.
* </p>
*
* @param ch character to repeat
* @param repeat number of times to repeat char, negative treated as zero
* @return String with repeated character
* @see #repeat(String, int)
*/
public static String repeat(char ch, int repeat) {
char[] buf = new char[repeat];
for (int i = repeat - 1; i >= 0; i--) {
buf[i] = ch;
}
return new String(buf);
}
/**
* <p>Right pad a String with spaces (' ').</p>
*
* <p>The String is padded to the size of {@code size}.</p>
*
* <pre>
* StringUtils.rightPad(null, *) = null
* StringUtils.rightPad("", 3) = " "
* StringUtils.rightPad("bat", 3) = "bat"
* StringUtils.rightPad("bat", 5) = "bat "
* StringUtils.rightPad("bat", 1) = "bat"
* StringUtils.rightPad("bat", -1) = "bat"
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @return right padded String or original String if no padding is necessary,
* {@code null} if null String input
*/
public static String rightPad(String str, int size) {
return rightPad(str, size, ' ');
}
/**
* <p>Right pad a String with a specified character.</p>
*
* <p>The String is padded to the size of {@code size}.</p>
*
* <pre>
* StringUtils.rightPad(null, *, *) = null
* StringUtils.rightPad("", 3, 'z') = "zzz"
* StringUtils.rightPad("bat", 3, 'z') = "bat"
* StringUtils.rightPad("bat", 5, 'z') = "batzz"
* StringUtils.rightPad("bat", 1, 'z') = "bat"
* StringUtils.rightPad("bat", -1, 'z') = "bat"
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padChar the character to pad with
* @return right padded String or original String if no padding is necessary,
* {@code null} if null String input
* @since 2.0
*/
public static String rightPad(String str, int size, char padChar) {
if (str == null) {
return null;
}
int pads = size - str.length();
if (pads <= 0) {
return str; // returns original String when possible
}
if (pads > PAD_LIMIT) {
return rightPad(str, size, String.valueOf(padChar));
}
return str.concat(repeat(padChar, pads));
}
/**
* <p>Right pad a String with a specified String.</p>
*
* <p>The String is padded to the size of {@code size}.</p>
*
* <pre>
* StringUtils.rightPad(null, *, *) = null
* StringUtils.rightPad("", 3, "z") = "zzz"
* StringUtils.rightPad("bat", 3, "yz") = "bat"
* StringUtils.rightPad("bat", 5, "yz") = "batyz"
* StringUtils.rightPad("bat", 8, "yz") = "batyzyzy"
* StringUtils.rightPad("bat", 1, "yz") = "bat"
* StringUtils.rightPad("bat", -1, "yz") = "bat"
* StringUtils.rightPad("bat", 5, null) = "bat "
* StringUtils.rightPad("bat", 5, "") = "bat "
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padStr the String to pad with, null or empty treated as single space
* @return right padded String or original String if no padding is necessary,
* {@code null} if null String input
*/
public static String rightPad(String str, int size, String padStr) {
if (str == null) {
return null;
}
if (isEmpty(padStr)) {
padStr = " ";
}
int padLen = padStr.length();
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str; // returns original String when possible
}
if (padLen == 1 && pads <= PAD_LIMIT) {
return rightPad(str, size, padStr.charAt(0));
}
if (pads == padLen) {
return str.concat(padStr);
} else if (pads < padLen) {
return str.concat(padStr.substring(0, pads));
} else {
char[] padding = new char[pads];
char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return str.concat(new String(padding));
}
}
/**
* <p>Left pad a String with spaces (' ').</p>
*
* <p>The String is padded to the size of {@code size}.</p>
*
* <pre>
* StringUtils.leftPad(null, *) = null
* StringUtils.leftPad("", 3) = " "
* StringUtils.leftPad("bat", 3) = "bat"
* StringUtils.leftPad("bat", 5) = " bat"
* StringUtils.leftPad("bat", 1) = "bat"
* StringUtils.leftPad("bat", -1) = "bat"
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @return left padded String or original String if no padding is necessary,
* {@code null} if null String input
*/
public static String leftPad(String str, int size) {
return leftPad(str, size, ' ');
}
/**
* <p>Left pad a String with a specified character.</p>
*
* <p>Pad to a size of {@code size}.</p>
*
* <pre>
* StringUtils.leftPad(null, *, *) = null
* StringUtils.leftPad("", 3, 'z') = "zzz"
* StringUtils.leftPad("bat", 3, 'z') = "bat"
* StringUtils.leftPad("bat", 5, 'z') = "zzbat"
* StringUtils.leftPad("bat", 1, 'z') = "bat"
* StringUtils.leftPad("bat", -1, 'z') = "bat"
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padChar the character to pad with
* @return left padded String or original String if no padding is necessary,
* {@code null} if null String input
* @since 2.0
*/
public static String leftPad(String str, int size, char padChar) {
if (str == null) {
return null;
}
int pads = size - str.length();
if (pads <= 0) {
return str; // returns original String when possible
}
if (pads > PAD_LIMIT) {
return leftPad(str, size, String.valueOf(padChar));
}
return repeat(padChar, pads).concat(str);
}
/**
* <p>Left pad a String with a specified String.</p>
*
* <p>Pad to a size of {@code size}.</p>
*
* <pre>
* StringUtils.leftPad(null, *, *) = null
* StringUtils.leftPad("", 3, "z") = "zzz"
* StringUtils.leftPad("bat", 3, "yz") = "bat"
* StringUtils.leftPad("bat", 5, "yz") = "yzbat"
* StringUtils.leftPad("bat", 8, "yz") = "yzyzybat"
* StringUtils.leftPad("bat", 1, "yz") = "bat"
* StringUtils.leftPad("bat", -1, "yz") = "bat"
* StringUtils.leftPad("bat", 5, null) = " bat"
* StringUtils.leftPad("bat", 5, "") = " bat"
* </pre>
*
* @param str the String to pad out, may be null
* @param size the size to pad to
* @param padStr the String to pad with, null or empty treated as single space
* @return left padded String or original String if no padding is necessary,
* {@code null} if null String input
*/
public static String leftPad(String str, int size, String padStr) {
if (str == null) {
return null;
}
if (isEmpty(padStr)) {
padStr = " ";
}
int padLen = padStr.length();
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str; // returns original String when possible
}
if (padLen == 1 && pads <= PAD_LIMIT) {
return leftPad(str, size, padStr.charAt(0));
}
if (pads == padLen) {
return padStr.concat(str);
} else if (pads < padLen) {
return padStr.substring(0, pads).concat(str);
} else {
char[] padding = new char[pads];
char[] padChars = padStr.toCharArray();
for (int i = 0; i < pads; i++) {
padding[i] = padChars[i % padLen];
}
return new String(padding).concat(str);
}
}
/**
* Gets a CharSequence length or {@code 0} if the CharSequence is
* {@code null}.
*
* @param cs
* a CharSequence or {@code null}
* @return CharSequence length or {@code 0} if the CharSequence is
* {@code null}.
* @since 2.4
* @since 3.0 Changed signature from length(String) to length(CharSequence)
*/
public static int length(CharSequence cs) {
return cs == null ? 0 : cs.length();
}
// Centering
//-----------------------------------------------------------------------
/**
* <p>Centers a String in a larger String of size {@code size}
* using the space character (' ').<p>
*
* <p>If the size is less than the String length, the String is returned.
* A {@code null} String returns {@code null}.
* A negative size is treated as zero.</p>
*
* <p>Equivalent to {@code center(str, size, " ")}.</p>
*
* <pre>
* StringUtils.center(null, *) = null
* StringUtils.center("", 4) = " "
* StringUtils.center("ab", -1) = "ab"
* StringUtils.center("ab", 4) = " ab "
* StringUtils.center("abcd", 2) = "abcd"
* StringUtils.center("a", 4) = " a "
* </pre>
*
* @param str the String to center, may be null
* @param size the int size of new String, negative treated as zero
* @return centered String, {@code null} if null String input
*/
public static String center(String str, int size) {
return center(str, size, ' ');
}
/**
* <p>Centers a String in a larger String of size {@code size}.
* Uses a supplied character as the value to pad the String with.</p>
*
* <p>If the size is less than the String length, the String is returned.
* A {@code null} String returns {@code null}.
* A negative size is treated as zero.</p>
*
* <pre>
* StringUtils.center(null, *, *) = null
* StringUtils.center("", 4, ' ') = " "
* StringUtils.center("ab", -1, ' ') = "ab"
* StringUtils.center("ab", 4, ' ') = " ab"
* StringUtils.center("abcd", 2, ' ') = "abcd"
* StringUtils.center("a", 4, ' ') = " a "
* StringUtils.center("a", 4, 'y') = "yayy"
* </pre>
*
* @param str the String to center, may be null
* @param size the int size of new String, negative treated as zero
* @param padChar the character to pad the new String with
* @return centered String, {@code null} if null String input
* @since 2.0
*/
public static String center(String str, int size, char padChar) {
if (str == null || size <= 0) {
return str;
}
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str;
}
str = leftPad(str, strLen + pads / 2, padChar);
str = rightPad(str, size, padChar);
return str;
}
/**
* <p>Centers a String in a larger String of size {@code size}.
* Uses a supplied String as the value to pad the String with.</p>
*
* <p>If the size is less than the String length, the String is returned.
* A {@code null} String returns {@code null}.
* A negative size is treated as zero.</p>
*
* <pre>
* StringUtils.center(null, *, *) = null
* StringUtils.center("", 4, " ") = " "
* StringUtils.center("ab", -1, " ") = "ab"
* StringUtils.center("ab", 4, " ") = " ab"
* StringUtils.center("abcd", 2, " ") = "abcd"
* StringUtils.center("a", 4, " ") = " a "
* StringUtils.center("a", 4, "yz") = "yayz"
* StringUtils.center("abc", 7, null) = " abc "
* StringUtils.center("abc", 7, "") = " abc "
* </pre>
*
* @param str the String to center, may be null
* @param size the int size of new String, negative treated as zero
* @param padStr the String to pad the new String with, must not be null or empty
* @return centered String, {@code null} if null String input
* @throws IllegalArgumentException if padStr is {@code null} or empty
*/
public static String center(String str, int size, String padStr) {
if (str == null || size <= 0) {
return str;
}
if (isEmpty(padStr)) {
padStr = " ";
}
int strLen = str.length();
int pads = size - strLen;
if (pads <= 0) {
return str;
}
str = leftPad(str, strLen + pads / 2, padStr);
str = rightPad(str, size, padStr);
return str;
}
// Case conversion
//-----------------------------------------------------------------------
/**
* <p>Converts a String to upper case as per {@link String#toUpperCase()}.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.upperCase(null) = null
* StringUtils.upperCase("") = ""
* StringUtils.upperCase("aBc") = "ABC"
* </pre>
*
* <p><strong>Note:</strong> As described in the documentation for {@link String#toUpperCase()},
* the result of this method is affected by the current locale.
* For platform-independent case transformations, the method {@link #lowerCase(String, Locale)}
* should be used with a specific locale (e.g. {@link Locale#ENGLISH}).</p>
*
* @param str the String to upper case, may be null
* @return the upper cased String, {@code null} if null String input
*/
public static String upperCase(String str) {
if (str == null) {
return null;
}
return str.toUpperCase();
}
/**
* <p>Converts a String to upper case as per {@link String#toUpperCase(Locale)}.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.upperCase(null, Locale.ENGLISH) = null
* StringUtils.upperCase("", Locale.ENGLISH) = ""
* StringUtils.upperCase("aBc", Locale.ENGLISH) = "ABC"
* </pre>
*
* @param str the String to upper case, may be null
* @param locale the locale that defines the case transformation rules, must not be null
* @return the upper cased String, {@code null} if null String input
* @since 2.5
*/
public static String upperCase(String str, Locale locale) {
if (str == null) {
return null;
}
return str.toUpperCase(locale);
}
/**
* <p>Converts a String to lower case as per {@link String#toLowerCase()}.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.lowerCase(null) = null
* StringUtils.lowerCase("") = ""
* StringUtils.lowerCase("aBc") = "abc"
* </pre>
*
* <p><strong>Note:</strong> As described in the documentation for {@link String#toLowerCase()},
* the result of this method is affected by the current locale.
* For platform-independent case transformations, the method {@link #lowerCase(String, Locale)}
* should be used with a specific locale (e.g. {@link Locale#ENGLISH}).</p>
*
* @param str the String to lower case, may be null
* @return the lower cased String, {@code null} if null String input
*/
public static String lowerCase(String str) {
if (str == null) {
return null;
}
return str.toLowerCase();
}
/**
* <p>Converts a String to lower case as per {@link String#toLowerCase(Locale)}.</p>
*
* <p>A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.lowerCase(null, Locale.ENGLISH) = null
* StringUtils.lowerCase("", Locale.ENGLISH) = ""
* StringUtils.lowerCase("aBc", Locale.ENGLISH) = "abc"
* </pre>
*
* @param str the String to lower case, may be null
* @param locale the locale that defines the case transformation rules, must not be null
* @return the lower cased String, {@code null} if null String input
* @since 2.5
*/
public static String lowerCase(String str, Locale locale) {
if (str == null) {
return null;
}
return str.toLowerCase(locale);
}
/**
* <p>Capitalizes a String changing the first letter to title case as
* per {@link Character#toTitleCase(char)}. No other letters are changed.</p>
*
* <p>For a word based algorithm, see {@link org.apache.commons.lang3.text.WordUtils#capitalize(String)}.
* A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.capitalize(null) = null
* StringUtils.capitalize("") = ""
* StringUtils.capitalize("cat") = "Cat"
* StringUtils.capitalize("cAt") = "CAt"
* </pre>
*
* @param str the String to capitalize, may be null
* @return the capitalized String, {@code null} if null String input
* @see org.apache.commons.lang3.text.WordUtils#capitalize(String)
* @see #uncapitalize(String)
* @since 2.0
*/
public static String capitalize(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return str;
}
return new StringBuilder(strLen)
.append(Character.toTitleCase(str.charAt(0)))
.append(str.substring(1))
.toString();
}
/**
* <p>Uncapitalizes a String changing the first letter to title case as
* per {@link Character#toLowerCase(char)}. No other letters are changed.</p>
*
* <p>For a word based algorithm, see {@link org.apache.commons.lang3.text.WordUtils#uncapitalize(String)}.
* A {@code null} input String returns {@code null}.</p>
*
* <pre>
* StringUtils.uncapitalize(null) = null
* StringUtils.uncapitalize("") = ""
* StringUtils.uncapitalize("Cat") = "cat"
* StringUtils.uncapitalize("CAT") = "cAT"
* </pre>
*
* @param str the String to uncapitalize, may be null
* @return the uncapitalized String, {@code null} if null String input
* @see org.apache.commons.lang3.text.WordUtils#uncapitalize(String)
* @see #capitalize(String)
* @since 2.0
*/
public static String uncapitalize(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return str;
}
return new StringBuilder(strLen)
.append(Character.toLowerCase(str.charAt(0)))
.append(str.substring(1))
.toString();
}
/**
* <p>Swaps the case of a String changing upper and title case to
&nb |