RequestAttributeMatcher


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  
22  import java.util.HashMap  ;
23  import java.util.Map  ;
24  
25  /**
26   * This class allows for matching based on a request attribute.
27   * If the specified request attribute exists, its string representation
28   * is retrieved for later sitemap substitution.
29   *
30   * <p><b>Example:</b></p>
31   * <pre>
32   * &lt;map:match type="request-attribute" pattern="next"&gt;
33   *     &lt;map:redirect-to SRC="{1}"/&gt;
34   * &lt;/map:match&gt;
35   * </pre>
36   *
37   * @author <a HREF="mailto:vgritsenko@apache.org">Vadim Gritsenko</a>
38   * @version CVS $Id: RequestAttributeMatcher.java 30932 2004-07-29 17:35:38Z vgritsenko $
39   */
40  public class RequestAttributeMatcher implements Matcher, ThreadSafe
41  {
42      /**
43       * Match method to see if the request attribute exists. If it does
44       * have a value the string represenation of attribute is added to
45       * the array list for later sitemap substitution.
46       *
47       * @param pattern name of request attribute to find
48       * @param objectModel environment passed through via cocoon
49       * @return null or map containing value of request attribute 'pattern'
50       */
51      public Map   match(String   pattern, Map   objectModel, Parameters parameters) {
52  
53          Object   attribute = ObjectModelHelper.getRequest(objectModel).getAttribute(pattern);
54  
55          if (attribute == null) {
56              return null;
57          } else {
58              Map   map = new HashMap  ();
59              map.put("1", attribute.toString());
60              return map;
61          }
62      }
63  }
64
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