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1   //========================================================================
2   //$Id: RegexRule.java 966 2008-04-17 13:53:44Z gregw $
3   //Copyright 2004-2005 Mort Bay Consulting Pty. Ltd.
4   //------------------------------------------------------------------------
5   //Licensed under the Apache License, Version 2.0 (the "License");
6   //you may not use this file except in compliance with the License.
7   //You may obtain a copy of the License at 
8   //http://www.apache.org/licenses/LICENSE-2.0
9   //Unless required by applicable law or agreed to in writing, software
10  //distributed under the License is distributed on an "AS IS" BASIS,
11  //WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  //See the License for the specific language governing permissions and
13  //limitations under the License.
14  //========================================================================
15  package org.mortbay.jetty.handler.rewrite;
16  
17  import java.io.IOException;
18  import java.util.regex.Matcher;
19  import java.util.regex.Pattern;
20  
21  import javax.servlet.http.HttpServletRequest;
22  import javax.servlet.http.HttpServletResponse;
23  
24  
25  /**
26   * Abstract rule to use as a base class for rules that match with a regular expression.
27   */
28  public abstract class RegexRule extends Rule
29  {
30      protected Pattern _regex; 
31  
32      /* ------------------------------------------------------------ */
33      /**
34       * Sets the regular expression string used to match with string URI.
35       * 
36       * @param regex the regular expression.
37       */
38      public void setRegex(String regex)
39      {
40          _regex=Pattern.compile(regex);
41      }
42  
43      /* ------------------------------------------------------------ */
44      /**
45       * @return get the regular expression
46       */
47      public String getRegex()
48      {
49          return _regex==null?null:_regex.pattern();
50      }
51      
52  
53      /* ------------------------------------------------------------ */
54      public String matchAndApply(String target, HttpServletRequest request, HttpServletResponse response) throws IOException
55      {
56          Matcher matcher=_regex.matcher(target);
57          boolean matches = matcher.matches();
58          if (matches)
59              return apply(target,request,response, matcher);
60          return null;
61      }
62  
63      /* ------------------------------------------------------------ */
64      /** 
65       * Apply this rule to the request/response pair.
66       * Called by {@link #matchAndApply(String, HttpServletRequest, HttpServletResponse)} if the regex matches.
67       * @param target field to attempt match
68       * @param request request object
69       * @param response response object
70       * @param matcher The Regex matcher that matched the request (with capture groups available for replacement).
71       * @return The target (possible updated).
72       * @throws IOException exceptions dealing with operating on request or response objects
73       */
74      protected abstract String apply(String target, HttpServletRequest request, HttpServletResponse response, Matcher matcher) throws IOException;
75      
76  
77      /* ------------------------------------------------------------ */
78      /**
79       * Returns the regular expression string.
80       */
81      public String toString()
82      {
83          return super.toString()+"["+_regex+"]";
84      }
85  }