/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software
* License version 1.1, a copy of which has been included with this
* distribution in the LICENSE.txt file. */
package org.apache.log4j.helpers;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.spi.LocationInfo;
/**
Utility class for transforming strings.
@author Ceki Gülcü
@author Michael A. McAngus
*/
public class Transform {
private static final String CDATA_START = "<![CDATA[";
private static final String CDATA_END = "]]>";
private static final String CDATA_PSEUDO_END = "]]>";
private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START;
private static final int CDATA_END_LEN = CDATA_END.length();
/**
* This method takes a string which may contain HTML tags (ie,
* <b>, <table>, etc) and replaces any '<' and '>'
* characters with respective predefined entity references.
*
* @param input The text to be converted.
* @return The input string with the characters '<' and '>' replaced with
* &lt; and &gt; respectively.
* */
static public String escapeTags(String input) {
//Check if the string is null or zero length -- if so, return
//what was sent in.
if( input == null || input.length() == 0 ) {
return input;
}
//Use a StringBuffer in lieu of String concatenation -- it is
//much more efficient this way.
StringBuffer buf = new StringBuffer(input.length() + 6);
char ch = ' ';
int len = input.length();
for(int i=0; i < len; i++) {
ch = input.charAt(i);
if(ch == '<') {
buf.append("<");
} else if(ch == '>') {
buf.append(">");
} else {
buf.append(ch);
}
}
return buf.toString();
}
/**
* Ensures that embeded CDEnd strings (]]>) are handled properly
* within message, NDC and throwable tag text.
*
* @param buf StringBuffer holding the XML data to this point. The
* initial CDStart (<![CDATA[) and final CDEnd (]]>) of the CDATA
* section are the responsibility of the calling method.
* @param str The String that is inserted into an existing CDATA Section within buf.
* */
static public void appendEscapingCDATA(StringBuffer buf, String str) {
if(str == null) {
buf.append("");
return;
}
int end = str.indexOf(CDATA_END);
if (end < 0) {
buf.append(str);
return;
}
int start = 0;
while (end > -1) {
buf.append(str.substring(start,end));
buf.append(CDATA_EMBEDED_END);
start = end + CDATA_END_LEN;
if (start < str.length()) {
end = str.indexOf(CDATA_END, start);
} else {
return;
}
}
buf.append(str.substring(start));
}
}
|