1 // ========================================================================
2 // Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13
14 package org.eclipse.jetty.server.handler;
15
16 import java.io.IOException;
17
18 import javax.servlet.ServletException;
19 import javax.servlet.http.HttpServletRequest;
20 import javax.servlet.http.HttpServletResponse;
21
22 import org.eclipse.jetty.server.Handler;
23 import org.eclipse.jetty.server.Request;
24 import org.eclipse.jetty.server.Server;
25 import org.eclipse.jetty.util.component.LifeCycle;
26
27 /* ------------------------------------------------------------ */
28 /** A <code>HandlerWrapper</code> acts as a {@link Handler} but delegates the {@link Handler#handle handle} method and
29 * {@link LifeCycle life cycle} events to a delegate. This is primarily used to implement the <i>Decorator</i> pattern.
30 *
31 */
32 public class HandlerWrapper extends AbstractHandlerContainer
33 {
34 protected Handler _handler;
35
36 /* ------------------------------------------------------------ */
37 /**
38 *
39 */
40 public HandlerWrapper()
41 {
42 }
43
44 /* ------------------------------------------------------------ */
45 /**
46 * @return Returns the handlers.
47 */
48 public Handler getHandler()
49 {
50 return _handler;
51 }
52
53 /* ------------------------------------------------------------ */
54 /**
55 * @return Returns the handlers.
56 */
57 public Handler[] getHandlers()
58 {
59 if (_handler==null)
60 return new Handler[0];
61 return new Handler[] {_handler};
62 }
63
64 /* ------------------------------------------------------------ */
65 /**
66 * @param handler Set the {@link Handler} which should be wrapped.
67 */
68 public void setHandler(Handler handler)
69 {
70 if (isStarted())
71 throw new IllegalStateException(STARTED);
72
73 Handler old_handler = _handler;
74 _handler = handler;
75 if (handler!=null)
76 handler.setServer(getServer());
77
78 if (getServer()!=null)
79 getServer().getContainer().update(this, old_handler, handler, "handler");
80 }
81
82 /* ------------------------------------------------------------ */
83 /*
84 * @see org.eclipse.thread.AbstractLifeCycle#doStart()
85 */
86 @Override
87 protected void doStart() throws Exception
88 {
89 if (_handler!=null)
90 _handler.start();
91 super.doStart();
92 }
93
94 /* ------------------------------------------------------------ */
95 /*
96 * @see org.eclipse.thread.AbstractLifeCycle#doStop()
97 */
98 @Override
99 protected void doStop() throws Exception
100 {
101 if (_handler!=null)
102 _handler.stop();
103 super.doStop();
104 }
105
106 /* ------------------------------------------------------------ */
107 public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
108 {
109 if (_handler!=null && isStarted())
110 {
111 _handler.handle(target,baseRequest, request, response);
112 }
113 }
114
115
116 /* ------------------------------------------------------------ */
117 @Override
118 public void setServer(Server server)
119 {
120 Server old_server=getServer();
121 if (server==old_server)
122 return;
123
124 if (isStarted())
125 throw new IllegalStateException(STARTED);
126
127 super.setServer(server);
128
129 Handler h=getHandler();
130 if (h!=null)
131 h.setServer(server);
132
133 if (server!=null && server!=old_server)
134 server.getContainer().update(this, null,_handler, "handler");
135 }
136
137
138 /* ------------------------------------------------------------ */
139 @Override
140 protected Object expandChildren(Object list, Class byClass)
141 {
142 return expandHandler(_handler,list,byClass);
143 }
144
145 /* ------------------------------------------------------------ */
146 public <H extends Handler> H getNestedHandlerByClass(Class<H> byclass)
147 {
148 HandlerWrapper h=this;
149 while (h!=null)
150 {
151 if (byclass.isInstance(h))
152 return (H)h;
153 Handler w = h.getHandler();
154 if (w instanceof HandlerWrapper)
155 h=(HandlerWrapper)w;
156 else break;
157 }
158 return null;
159
160 }
161
162 /* ------------------------------------------------------------ */
163 @Override
164 public void destroy()
165 {
166 if (!isStopped())
167 throw new IllegalStateException("!STOPPED");
168 Handler child=getHandler();
169 if (child!=null)
170 {
171 setHandler(null);
172 child.destroy();
173 }
174 super.destroy();
175 }
176
177 }