/*
* Copyright 2002-2008 the original author or authors.
*
* Licensed 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.springframework.util;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.util.Date;
import java.util.Enumeration;
import java.util.Properties;
/**
* Default implementation of the {@link PropertiesPersister} interface.
* Follows the native parsing of <code>java.util.Properties</code>.
*
* <p>Allows for reading from any Reader and writing to any Writer, for example
* to specify a charset for a properties file. This is a capability that standard
* <code>java.util.Properties</code> unfortunately lacks up until JDK 1.5:
* You can only load files using the ISO-8859-1 charset there.
*
* <p>Loading from and storing to a stream delegates to <code>Properties.load</code>
* and <code>Properties.store</code>, respectively, to be fully compatible with
* the Unicode conversion as implemented by the JDK Properties class. On JDK 1.6,
* <code>Properties.load/store</code> will also be used for readers/writers,
* effectively turning this class into a plain backwards compatibility adapter.
*
* <p>The persistence code that works with Reader/Writer follows the JDK's parsing
* strategy but does not implement Unicode conversion, because the Reader/Writer
* should already apply proper decoding/encoding of characters. If you use prefer
* to escape unicode characters in your properties files, do <i>not</i> specify
* an encoding for a Reader/Writer (like ReloadableResourceBundleMessageSource's
* "defaultEncoding" and "fileEncodings" properties).
*
* <p>As of Spring 1.2.2, this implementation also supports properties XML files,
* through the <code>loadFromXml</code> and <code>storeToXml</code> methods.
* The default implementations delegate to JDK 1.5's corresponding methods,
* throwing an exception if running on an older JDK. Those implementations
* could be subclassed to apply custom XML handling on JDK 1.4, for example.
*
* @author Juergen Hoeller
* @since 10.03.2004
* @see java.util.Properties
* @see java.util.Properties#load
* @see java.util.Properties#store
* @see org.springframework.context.support.ReloadableResourceBundleMessageSource#setPropertiesPersister
* @see org.springframework.context.support.ReloadableResourceBundleMessageSource#setDefaultEncoding
* @see org.springframework.context.support.ReloadableResourceBundleMessageSource#setFileEncodings
*/
public class DefaultPropertiesPersister implements PropertiesPersister {
// Determine whether Properties.load(Reader) is available (on JDK 1.6+)
private static final boolean loadFromReaderAvailable =
ClassUtils.hasMethod(Properties.class, "load", new Class[] {Reader.class});
// Determine whether Properties.store(Writer, String) is available (on JDK 1.6+)
private static final boolean storeToWriterAvailable =
ClassUtils.hasMethod(Properties.class, "store", new Class[] {Writer.class, String.class});
public void load(Properties props, InputStream is) throws IOException {
props.load(is);
}
public void load(Properties props, Reader reader) throws IOException {
if (loadFromReaderAvailable) {
// On JDK 1.6+
props.load(reader);
}
else {
// Fall back to manual parsing.
doLoad(props, reader);
}
}
protected void doLoad(Properties props, Reader reader) throws IOException {
BufferedReader in = new BufferedReader(reader);
while (true) {
String line = in.readLine();
if (line == null) {
return;
}
line = StringUtils.trimLeadingWhitespace(line);
if (line.length() > 0) {
char firstChar = line.charAt(0);
if (firstChar != '#' && firstChar != '!') {
while (endsWithContinuationMarker(line)) {
String nextLine = in.readLine();
line = line.substring(0, line.length() - 1);
if (nextLine != null) {
line += StringUtils.trimLeadingWhitespace(nextLine);
}
}
int separatorIndex = line.indexOf("=");
if (separatorIndex == -1) {
separatorIndex = line.indexOf(":");
}
String key = (separatorIndex != -1 ? line.substring(0, separatorIndex) : line);
String value = (separatorIndex != -1) ? line.substring(separatorIndex + 1) : "";
key = StringUtils.trimTrailingWhitespace(key);
value = StringUtils.trimLeadingWhitespace(value);
props.put(unescape(key), unescape(value));
}
}
}
}
protected boolean endsWithContinuationMarker(String line) {
boolean evenSlashCount = true;
int index = line.length() - 1;
while (index >= 0 && line.charAt(index) == '\\') {
evenSlashCount = !evenSlashCount;
index--;
}
return !evenSlashCount;
}
protected String unescape(String str) {
StringBuilder result = new StringBuilder(str.length());
for (int index = 0; index < str.length();) {
char c = str.charAt(index++);
if (c == '\\') {
c = str.charAt(index++);
if (c == 't') {
c = '\t';
}
else if (c == 'r') {
c = '\r';
}
else if (c == 'n') {
c = '\n';
}
else if (c == 'f') {
c = '\f';
}
}
result.append(c);
}
return result.toString();
}
public void store(Properties props, OutputStream os, String header) throws IOException {
props.store(os, header);
}
public void store(Properties props, Writer writer, String header) throws IOException {
if (storeToWriterAvailable) {
// On JDK 1.6+
props.store(writer, header);
}
else {
// Fall back to manual parsing.
doStore(props, writer, header);
}
}
protected void doStore(Properties props, Writer writer, String header) throws IOException {
BufferedWriter out = new BufferedWriter(writer);
if (header != null) {
out.write("#" + header);
out.newLine();
}
out.write("#" + new Date());
out.newLine();
for (Enumeration keys = props.keys(); keys.hasMoreElements();) {
String key = (String) keys.nextElement();
String val = props.getProperty(key);
out.write(escape(key, true) + "=" + escape(val, false));
out.newLine();
}
out.flush();
}
protected String escape(String str, boolean isKey) {
int len = str.length();
StringBuilder result = new StringBuilder(len * 2);
for (int index = 0; index < len; index++) {
char c = str.charAt(index);
switch (c) {
case ' ':
if (index == 0 || isKey) {
result.append('\\');
}
result.append(' ');
break;
case '\\':
result.append("\\\\");
break;
case '\t':
result.append("\\t");
break;
case '\n':
result.append("\\n");
break;
case '\r':
result.append("\\r");
break;
case '\f':
result.append("\\f");
break;
default:
if ("=: \t\r\n\f#!".indexOf(c) != -1) {
result.append('\\');
}
result.append(c);
}
}
return result.toString();
}
public void loadFromXml(Properties props, InputStream is) throws IOException {
try {
props.loadFromXML(is);
}
catch (NoSuchMethodError err) {
throw new IOException("Cannot load properties XML file - not running on JDK 1.5+: " + err.getMessage());
}
}
public void storeToXml(Properties props, OutputStream os, String header) throws IOException {
try {
props.storeToXML(os, header);
}
catch (NoSuchMethodError err) {
throw new IOException("Cannot store properties XML file - not running on JDK 1.5+: " + err.getMessage());
}
}
public void storeToXml(Properties props, OutputStream os, String header, String encoding) throws IOException {
try {
props.storeToXML(os, header, encoding);
}
catch (NoSuchMethodError err) {
throw new IOException("Cannot store properties XML file - not running on JDK 1.5+: " + err.getMessage());
}
}
}
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