package org.jsoup.helper;
import java.util.Collection;
import java.util.Iterator;
/**
* A minimal String utility class. Designed for interal jsoup use only.
*/
public final class StringUtil {
// memoised padding up to 10
private static final String[] padding = {"", " ", " ", " ", " ", " ", " ", " ", " ", " ", " "};
/**
* Join a collection of strings by a seperator
* @param strings collection of string objects
* @param sep string to place between strings
* @return joined string
*/
public static String join(Collection strings, String sep) {
return join(strings.iterator(), sep);
}
/**
* Join a collection of strings by a seperator
* @param strings iterator of string objects
* @param sep string to place between strings
* @return joined string
*/
public static String join(Iterator strings, String sep) {
if (!strings.hasNext())
return "";
String start = strings.next().toString();
if (!strings.hasNext()) // only one, avoid builder
return start;
StringBuilder sb = new StringBuilder(64).append(start);
while (strings.hasNext()) {
sb.append(sep);
sb.append(strings.next());
}
return sb.toString();
}
/**
* Returns space padding
* @param width amount of padding desired
* @return string of spaces * width
*/
public static String padding(int width) {
if (width < 0)
throw new IllegalArgumentException("width must be > 0");
if (width < padding.length)
return padding[width];
char[] out = new char[width];
for (int i = 0; i < width; i++)
out[i] = ' ';
return String.valueOf(out);
}
/**
* Tests if a string is blank: null, emtpy, or only whitespace (" ", \r\n, \t, etc)
* @param string string to test
* @return if string is blank
*/
public static boolean isBlank(String string) {
if (string == null || string.length() == 0)
return true;
int l = string.length();
for (int i = 0; i < l; i++) {
if (!Character.isWhitespace(string.codePointAt(i)))
return false;
}
return true;
}
/**
* Tests if a string is numeric, i.e. contains only digit characters
* @param string string to test
* @return true if only digit chars, false if empty or null or contains non-digit chrs
*/
public static boolean isNumeric(String string) {
if (string == null || string.length() == 0)
return false;
int l = string.length();
for (int i = 0; i < l; i++) {
if (!Character.isDigit(string.codePointAt(i)))
return false;
}
return true;
}
public static String normaliseWhitespace(String string) {
StringBuilder sb = new StringBuilder(string.length());
boolean lastWasWhite = false;
boolean modified = false;
int l = string.length();
for (int i = 0; i < l; i++) {
int c = string.codePointAt(i);
if (Character.isWhitespace(c)) {
if (lastWasWhite) {
modified = true;
continue;
}
if (c != ' ')
modified = true;
sb.append(' ');
lastWasWhite = true;
}
else {
sb.appendCodePoint(c);
lastWasWhite = false;
}
}
return modified ? sb.toString() : string;
}
public static boolean in(String needle, String... haystack) {
for (String hay : haystack) {
if (hay.equals(needle))
return true;
}
return false;
}
}
|