HeaderMatcher


1   /*
2    * Copyright 1999-2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.cocoon.matching;
17  
18  import org.apache.avalon.framework.parameters.Parameters;
19  import org.apache.avalon.framework.thread.ThreadSafe;
20  import org.apache.cocoon.environment.ObjectModelHelper;
21  import org.apache.cocoon.environment.Request;
22  
23  import java.util.HashMap  ;
24  import java.util.Map  ;
25  
26  /**
27   * This class allows for matching based on a request header.
28   * If the specified request header parameter exists, its value is
29   * retrieved for later sitemap substitution.
30   *
31   * <p><b>Example:</b></p>
32   * <pre>
33   * &lt;map:match type="header" pattern="referer"&gt;
34   *     &lt;map:redirect-to uri="{1}"/&gt;
35   * &lt;/map:match&gt;
36   * </pre>
37   *
38   * @author <a HREF="mailto:vgritsenko@apache.org">Vadim Gritsenko</a>
39   * @version CVS $Id: HeaderMatcher.java 30932 2004-07-29 17:35:38Z vgritsenko $
40   */
41  public class HeaderMatcher implements Matcher, ThreadSafe
42  {
43      /**
44       * Match method to see if the request header exists. If it does
45       * have a value the header added to the array list for later
46       * sitemap substitution.
47       *
48       * @param pattern name of request header to find
49       * @param objectModel environment passed through via cocoon
50       * @return null or map containing value of request header 'pattern'
51       */
52      public Map   match(String   pattern, Map   objectModel, Parameters parameters) {
53          Request request = ObjectModelHelper.getRequest(objectModel);
54  
55          String   value = request.getHeader(pattern);
56          if (value == null) {
57              return null; // no request header defined
58          } else {
59              Map   map = new HashMap  ();
60              map.put("1", value);
61              return map; // request header defined, return map
62          }
63      }
64  }
65
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