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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  
40      private static final String CDATA_END = "]]>";
41  
42      private static final String CDATA_PSEUDO_END = "]]&gt;";
43  
44      private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START;
45  
46      private static final int CDATA_END_LEN = CDATA_END.length();
47  
48      /**
49       * This method takes a string which may contain HTML tags (ie,
50       * &lt;b&gt;, &lt;table&gt;, etc) and replaces any
51       * '<',  '>' , '&' or '"'
52       * characters with respective predefined entity references.
53       *
54       * @param input The text to be converted.
55       * @return The input string with the special characters replaced.
56       * */
57      static public String escapeTags(final String input) {
58          // Check if the string is null, zero length or devoid of special characters
59          // if so, return what was sent in.
60  
61          if (input == null
62                  || input.length() == 0
63                  || (input.indexOf('"') == -1 && input.indexOf('&') == -1 && input.indexOf('<') == -1 && input
64                          .indexOf('>') == -1)) {
65              return input;
66          }
67  
68          StringBuilder buf = new StringBuilder(input.length() + 6);
69          char ch;
70  
71          int len = input.length();
72          for (int i = 0; i < len; i++) {
73              ch = input.charAt(i);
74              if (ch > '>') {
75                  buf.append(ch);
76              } else if (ch == '<') {
77                  buf.append("&lt;");
78              } else if (ch == '>') {
79                  buf.append("&gt;");
80              } else if (ch == '&') {
81                  buf.append("&amp;");
82              } else if (ch == '"') {
83                  buf.append("&quot;");
84              } else {
85                  buf.append(ch);
86              }
87          }
88          return buf.toString();
89      }
90  
91      /**
92       * Ensures that embeded CDEnd strings (]]>) are handled properly
93       * within message, NDC and throwable tag text.
94       *
95       * @param buf StringBuffer holding the XML data to this point.  The
96       * initial CDStart (<![CDATA[) and final CDEnd (]]>) of the CDATA
97       * section are the responsibility of the calling method.
98       * @param str The String that is inserted into an existing CDATA Section within buf.
99       * */
100     static public void appendEscapingCDATA(final StringBuffer buf, final String str) {
101         if (str != null) {
102             int end = str.indexOf(CDATA_END);
103             if (end < 0) {
104                 buf.append(str);
105             } else {
106                 int start = 0;
107                 while (end > -1) {
108                     buf.append(str.substring(start, end));
109                     buf.append(CDATA_EMBEDED_END);
110                     start = end + CDATA_END_LEN;
111                     if (start < str.length()) {
112                         end = str.indexOf(CDATA_END, start);
113                     } else {
114                         return;
115                     }
116                 }
117                 buf.append(str.substring(start));
118             }
119         }
120     }
121 
122     /**
123      * convert a Throwable into an array of Strings
124      * @param throwable
125      * @return string representation of the throwable
126      */
127     public static String[] getThrowableStrRep(Throwable throwable) {
128         StringWriter sw = new StringWriter();
129         PrintWriter pw = new PrintWriter(sw);
130         throwable.printStackTrace(pw);
131         pw.flush();
132         LineNumberReader reader = new LineNumberReader(new StringReader(sw.toString()));
133         ArrayList<String> lines = new ArrayList<String>();
134         try {
135             String line = reader.readLine();
136             while (line != null) {
137                 lines.add(line);
138                 line = reader.readLine();
139             }
140         } catch (IOException ex) {
141             lines.add(ex.toString());
142         }
143         String[] rep = new String[lines.size()];
144         lines.toArray(rep);
145         return rep;
146     }
147 
148 }