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
71 if (getServer()!=null)
72 getServer().getContainer().update(this, old_handler, handler, "handler");
73
74 if (handler!=null)
75 {
76 handler.setServer(getServer());
77 if (isStarted())
78 handler.start();
79 }
80
81 _handler = handler;
82
83 // if there is an old handler and it was started, stop it
84 if (old_handler != null && isStarted())
85 {
86 old_handler.stop();
87 }
88
89 }
90 catch(RuntimeException e)
91 {
92 throw e;
93 }
94 catch(Exception e)
95 {
96 throw new RuntimeException(e);
97 }
98 }
99
100 /* ------------------------------------------------------------ */
101 /*
102 * @see org.eclipse.thread.AbstractLifeCycle#doStart()
103 */
104 @Override
105 protected void doStart() throws Exception
106 {
107 if (_handler!=null)
108 _handler.start();
109 super.doStart();
110 }
111
112 /* ------------------------------------------------------------ */
113 /*
114 * @see org.eclipse.thread.AbstractLifeCycle#doStop()
115 */
116 @Override
117 protected void doStop() throws Exception
118 {
119 super.doStop();
120 if (_handler!=null)
121 _handler.stop();
122 }
123
124 /* ------------------------------------------------------------ */
125 /*
126 * @see org.eclipse.jetty.server.server.EventHandler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
127 */
128 public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
129 {
130 if (_handler!=null && isStarted())
131 {
132 _handler.handle(target,baseRequest, request, response);
133 }
134 }
135
136
137 /* ------------------------------------------------------------ */
138 @Override
139 public void setServer(Server server)
140 {
141 Server old_server=getServer();
142 if (server==old_server)
143 return;
144
145 if (isRunning())
146 throw new IllegalStateException(RUNNING);
147
148 super.setServer(server);
149
150 Handler h=getHandler();
151 if (h!=null)
152 h.setServer(server);
153
154 if (server!=null && server!=old_server)
155 server.getContainer().update(this, null,_handler, "handler");
156 }
157
158
159 /* ------------------------------------------------------------ */
160 @Override
161 protected Object expandChildren(Object list, Class byClass)
162 {
163 return expandHandler(_handler,list,byClass);
164 }
165
166
167 }