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
26 /* ------------------------------------------------------------ */
27 /** A <code>HandlerContainer</code> that allows a hot swap
28 * of a wrapped handler.
29 *
30 */
31 public class HotSwapHandler extends AbstractHandlerContainer
32 {
33 private volatile Handler _handler;
34
35 /* ------------------------------------------------------------ */
36 /**
37 *
38 */
39 public HotSwapHandler()
40 {
41 }
42
43 /* ------------------------------------------------------------ */
44 /**
45 * @return Returns the handlers.
46 */
47 public Handler getHandler()
48 {
49 return _handler;
50 }
51
52 /* ------------------------------------------------------------ */
53 /**
54 * @return Returns the handlers.
55 */
56 public Handler[] getHandlers()
57 {
58 return new Handler[] {_handler};
59 }
60
61 /* ------------------------------------------------------------ */
62 /**
63 * @param handler Set the {@link Handler} which should be wrapped.
64 */
65 public void setHandler(Handler handler)
66 {
67 try
68 {
69 Handler old_handler = _handler;
70 _handler = handler;
71 if (handler!=null)
72 {
73 handler.setServer(getServer());
74 if (isStarted())
75 handler.start();
76 }
77
78 if (getServer()!=null)
79 getServer().getContainer().update(this, old_handler, handler, "handler");
80
81
82 // if there is an old handler and it was started, stop it
83 if (old_handler != null && isStarted())
84 {
85 old_handler.stop();
86 }
87
88 }
89 catch(RuntimeException e)
90 {
91 throw e;
92 }
93 catch(Exception e)
94 {
95 throw new RuntimeException(e);
96 }
97 }
98
99 /* ------------------------------------------------------------ */
100 /*
101 * @see org.eclipse.thread.AbstractLifeCycle#doStart()
102 */
103 @Override
104 protected void doStart() throws Exception
105 {
106 if (_handler!=null)
107 _handler.start();
108 super.doStart();
109 }
110
111 /* ------------------------------------------------------------ */
112 /*
113 * @see org.eclipse.thread.AbstractLifeCycle#doStop()
114 */
115 @Override
116 protected void doStop() throws Exception
117 {
118 super.doStop();
119 if (_handler!=null)
120 _handler.stop();
121 }
122
123 /* ------------------------------------------------------------ */
124 /*
125 * @see org.eclipse.jetty.server.server.EventHandler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
126 */
127 public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
128 {
129 if (_handler!=null && isStarted())
130 {
131 _handler.handle(target,baseRequest, request, response);
132 }
133 }
134
135
136 /* ------------------------------------------------------------ */
137 @Override
138 public void setServer(Server server)
139 {
140 Server old_server=getServer();
141 if (server==old_server)
142 return;
143
144 if (isRunning())
145 throw new IllegalStateException(RUNNING);
146
147 super.setServer(server);
148
149 Handler h=getHandler();
150 if (h!=null)
151 h.setServer(server);
152
153 if (server!=null && server!=old_server)
154 server.getContainer().update(this, null,_handler, "handler");
155 }
156
157 /* ------------------------------------------------------------ */
158 @Override
159 protected Object expandChildren(Object list, Class byClass)
160 {
161 return expandHandler(_handler,list,byClass);
162 }
163
164 /* ------------------------------------------------------------ */
165 @Override
166 public void destroy()
167 {
168 if (!isStopped())
169 throw new IllegalStateException("!STOPPED");
170 Handler child=getHandler();
171 if (child!=null)
172 {
173 setHandler(null);
174 child.destroy();
175 }
176 super.destroy();
177 }
178 }