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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.mina.util;
21  
22  import java.io.IOException;
23  import java.io.LineNumberReader;
24  import java.io.PrintWriter;
25  import java.io.StringReader;
26  import java.io.StringWriter;
27  import java.util.ArrayList;
28  
29  /**
30   * Utility class for working with xml data
31   *
32   * Implementation is heavily based on org.apache.log4j.helpers.Transform
33   * 
34   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
35   */
36  public class Transform {
37  
38      private static final String CDATA_START  = "<![CDATA[";
39      private static final String CDATA_END    = "]]>";
40      private static final String CDATA_PSEUDO_END = "]]&gt;";
41      private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START;
42      private static final int CDATA_END_LEN = CDATA_END.length();
43  
44      /**
45       * This method takes a string which may contain HTML tags (ie,
46       * &lt;b&gt;, &lt;table&gt;, etc) and replaces any
47       * '<',  '>' , '&' or '"'
48       * characters with respective predefined entity references.
49       *
50       * @param input The text to be converted.
51       * @return The input string with the special characters replaced.
52       * */
53      static public String escapeTags(final String input) {
54          // Check if the string is null, zero length or devoid of special characters
55          // if so, return what was sent in.
56  
57          if(input == null
58              || input.length() == 0
59              || (input.indexOf('"') == -1 &&
60              input.indexOf('&') == -1 &&
61              input.indexOf('<') == -1 &&
62              input.indexOf('>') == -1)) {
63              return input;
64          }
65  
66          StringBuilder buf = new StringBuilder(input.length() + 6);
67          char ch;
68  
69          int len = input.length();
70          for(int i=0; i < len; i++) {
71              ch = input.charAt(i);
72              if (ch > '>') {
73                  buf.append(ch);
74              } else if(ch == '<') {
75                  buf.append("&lt;");
76              } else if(ch == '>') {
77                  buf.append("&gt;");
78              } else if(ch == '&') {
79                  buf.append("&amp;");
80              } else if(ch == '"') {
81                  buf.append("&quot;");
82              } else {
83                  buf.append(ch);
84              }
85          }
86          return buf.toString();
87      }
88  
89      /**
90       * Ensures that embeded CDEnd strings (]]>) are handled properly
91       * within message, NDC and throwable tag text.
92       *
93       * @param buf StringBuffer holding the XML data to this point.  The
94       * initial CDStart (<![CDATA[) and final CDEnd (]]>) of the CDATA
95       * section are the responsibility of the calling method.
96       * @param str The String that is inserted into an existing CDATA Section within buf.
97       * */
98      static public void appendEscapingCDATA(final StringBuffer buf,
99                                             final String str) {
100         if (str != null) {
101             int end = str.indexOf(CDATA_END);
102             if (end < 0) {
103                 buf.append(str);
104             } else {
105                 int start = 0;
106                 while (end > -1) {
107                     buf.append(str.substring(start, end));
108                     buf.append(CDATA_EMBEDED_END);
109                     start = end + CDATA_END_LEN;
110                     if (start < str.length()) {
111                         end = str.indexOf(CDATA_END, start);
112                     } else {
113                         return;
114                     }
115                 }
116                 buf.append(str.substring(start));
117             }
118         }
119     }
120 
121     /**
122      * convert a Throwable into an array of Strings
123      * @param throwable
124      * @return string representation of the throwable
125      */
126     public static String[] getThrowableStrRep(Throwable throwable) {
127         StringWriter sw = new StringWriter();
128         PrintWriter pw = new PrintWriter(sw);
129         throwable.printStackTrace(pw);
130         pw.flush();
131         LineNumberReader reader = new LineNumberReader(new StringReader(sw.toString()));
132         ArrayList<String> lines = new ArrayList<String>();
133         try {
134             String line = reader.readLine();
135             while(line != null) {
136                 lines.add(line);
137                 line = reader.readLine();
138             }
139         } catch(IOException ex) {
140             lines.add(ex.toString());
141         }
142         String[] rep = new String[lines.size()];
143         lines.toArray(rep);
144         return rep;
145     }
146 
147 }