1   /*
2    * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/test/org/apache/commons/httpclient/server/HttpRequestHandlerChain.java,v 1.6 2004/11/28 15:44:39 olegk Exp $
3    * $Revision: 155418 $
4    * $Date: 2005-02-26 08:01:52 -0500 (Sat, 26 Feb 2005) $
5    *
6    * ====================================================================
7    *
8    *  Copyright 1999-2004 The Apache Software Foundation
9    *
10   *  Licensed under the Apache License, Version 2.0 (the "License");
11   *  you may not use this file except in compliance with the License.
12   *  You may obtain a copy of the License at
13   *
14   *      http://www.apache.org/licenses/LICENSE-2.0
15   *
16   *  Unless required by applicable law or agreed to in writing, software
17   *  distributed under the License is distributed on an "AS IS" BASIS,
18   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19   *  See the License for the specific language governing permissions and
20   *  limitations under the License.
21   * ====================================================================
22   *
23   * This software consists of voluntary contributions made by many
24   * individuals on behalf of the Apache Software Foundation.  For more
25   * information on the Apache Software Foundation, please see
26   * <http://www.apache.org/>.
27   *
28   * [Additional notices, if required by prior licensing conditions]
29   *
30   */
31  
32  package org.apache.commons.httpclient.server;
33  
34  import java.io.IOException;
35  import java.util.ArrayList;
36  import java.util.Iterator;
37  import java.util.List;
38  
39  /***
40   * Maintains a chain of {@link HttpRequestHandler}s where new request-handlers
41   * can be prepended/appended.
42   * 
43   * For each call to {@link #processRequest(ResponseWriter,SimpleHttpServerConnection,RequestLine,Header[])}
44   * we iterate over the chain from the start to the end, stopping as soon as a handler
45   * has claimed the output.
46   * 
47   * @author Christian Kohlschuetter
48   */
49  public class HttpRequestHandlerChain implements HttpRequestHandler {
50      
51      private List subhandlers = new ArrayList();
52      
53      public HttpRequestHandlerChain(final HttpRequestHandlerChain chain) {
54          super();
55          if (chain != null) {
56              this.subhandlers.clear();
57              this.subhandlers.addAll(chain.subhandlers);
58          }
59      }
60      
61      public HttpRequestHandlerChain() {
62          super();
63      }
64      
65      public synchronized void clear() {
66          subhandlers.clear();
67      }
68      
69      public synchronized void prependHandler(HttpRequestHandler handler) {
70          subhandlers.add(0,handler);
71      }
72      
73      public synchronized void appendHandler(HttpRequestHandler handler) {
74          subhandlers.add(handler);
75      }
76  
77      public synchronized boolean processRequest(
78          final SimpleHttpServerConnection conn,
79          final SimpleRequest request) throws IOException 
80      {
81          for(Iterator it=subhandlers.iterator();it.hasNext();) {
82              HttpRequestHandler h = (HttpRequestHandler)it.next();
83              boolean stop = h.processRequest(conn, request);
84              if (stop) {
85                  return true;
86              }
87          }
88          return false;
89      }
90  }