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