2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
18 package org.apache.log4j.helpers;
21 Utility class for transforming strings.
23 @author Ceki Gülcü
24 @author Michael A. McAngus
26 public class Transform {
28 private static final String CDATA_START = "<![CDATA[";
29 private static final String CDATA_END = "]]>";
30 private static final String CDATA_PSEUDO_END = "]]>";
31 private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START;
32 private static final int CDATA_END_LEN = CDATA_END.length();
35 * This method takes a string which may contain HTML tags (ie,
36 * <b>, <table>, etc) and replaces any
37 * '<', '>' , '&' or '"'
38 * characters with respective predefined entity references.
40 * @param input The text to be converted.
41 * @return The input string with the special characters replaced.
43 static public String escapeTags(final String input) {
44 //Check if the string is null, zero length or devoid of special characters
45 // if so, return what was sent in.
48 || input.length() == 0
49 || (input.indexOf('"') == -1 &&
50 input.indexOf('&') == -1 &&
51 input.indexOf('<') == -1 &&
52 input.indexOf('>') == -1)) {
56 //Use a StringBuffer in lieu of String concatenation -- it is
57 //much more efficient this way.
59 StringBuffer buf = new StringBuffer(input.length() + 6);
62 int len = input.length();
63 for(int i=0; i < len; i++) {
67 } else if(ch == '<') {
69 } else if(ch == '>') {
71 } else if(ch == '&') {
73 } else if(ch == '"') {
79 return buf.toString();
83 * Ensures that embeded CDEnd strings (]]>) are handled properly
84 * within message, NDC and throwable tag text.
86 * @param buf StringBuffer holding the XML data to this point. The
87 * initial CDStart (<![CDATA[) and final CDEnd (]]>) of the CDATA
88 * section are the responsibility of the calling method.
89 * @param str The String that is inserted into an existing CDATA Section within buf.
91 static public void appendEscapingCDATA(final StringBuffer buf,
94 int end = str.indexOf(CDATA_END);
100 buf.append(str.substring(start, end));
101 buf.append(CDATA_EMBEDED_END);
102 start = end + CDATA_END_LEN;
103 if (start < str.length()) {
104 end = str.indexOf(CDATA_END, start);
109 buf.append(str.substring(start));