1   /*
2    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/oac.hc3x/trunk/src/test/org/apache/commons/httpclient/server/HttpRequestHandlerChain.java $
3    * $Revision: 1425331 $
4    * $Date: 2012-12-22 19:29:41 +0100 (Sat, 22 Dec 2012) $
5    *
6    * ====================================================================
7    *
8    *  Licensed to the Apache Software Foundation (ASF) under one or more
9    *  contributor license agreements.  See the NOTICE file distributed with
10   *  this work for additional information regarding copyright ownership.
11   *  The ASF licenses this file to You under the Apache License, Version 2.0
12   *  (the "License"); you may not use this file except in compliance with
13   *  the License.  You may obtain a copy of the License at
14   *
15   *      http://www.apache.org/licenses/LICENSE-2.0
16   *
17   *  Unless required by applicable law or agreed to in writing, software
18   *  distributed under the License is distributed on an "AS IS" BASIS,
19   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20   *  See the License for the specific language governing permissions and
21   *  limitations under the License.
22   * ====================================================================
23   *
24   * This software consists of voluntary contributions made by many
25   * individuals on behalf of the Apache Software Foundation.  For more
26   * information on the Apache Software Foundation, please see
27   * <http://www.apache.org/>.
28   *
29   * [Additional notices, if required by prior licensing conditions]
30   *
31   */
32  
33  package org.apache.commons.httpclient.server;
34  
35  import java.io.IOException;
36  import java.util.ArrayList;
37  import java.util.Iterator;
38  import java.util.List;
39  
40  /***
41   * Maintains a chain of {@link HttpRequestHandler}s where new request-handlers
42   * can be prepended/appended.
43   * 
44   * For each call to {@link #processRequest(ResponseWriter,SimpleHttpServerConnection,RequestLine,Header[])}
45   * we iterate over the chain from the start to the end, stopping as soon as a handler
46   * has claimed the output.
47   * 
48   * @author Christian Kohlschuetter
49   */
50  public class HttpRequestHandlerChain implements HttpRequestHandler {
51      
52      private List subhandlers = new ArrayList();
53      
54      public HttpRequestHandlerChain(final HttpRequestHandlerChain chain) {
55          super();
56          if (chain != null) {
57              this.subhandlers.clear();
58              this.subhandlers.addAll(chain.subhandlers);
59          }
60      }
61      
62      public HttpRequestHandlerChain() {
63          super();
64      }
65      
66      public synchronized void clear() {
67          subhandlers.clear();
68      }
69      
70      public synchronized void prependHandler(HttpRequestHandler handler) {
71          subhandlers.add(0,handler);
72      }
73      
74      public synchronized void appendHandler(HttpRequestHandler handler) {
75          subhandlers.add(handler);
76      }
77  
78      public synchronized boolean processRequest(
79          final SimpleHttpServerConnection conn,
80          final SimpleRequest request) throws IOException 
81      {
82          for(Iterator it=subhandlers.iterator();it.hasNext();) {
83              HttpRequestHandler h = (HttpRequestHandler)it.next();
84              boolean stop = h.processRequest(conn, request);
85              if (stop) {
86                  return true;
87              }
88          }
89          return false;
90      }
91  }