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 if (isRunning())
72 throw new IllegalStateException(RUNNING);
73
74 Handler old_handler = _handler;
75
76 if (getServer()!=null)
77 getServer().getContainer().update(this, old_handler, handler, "handler");
78
79 if (handler!=null)
80 {
81 handler.setServer(getServer());
82 if (isStarted())
83 handler.start();
84 }
85
86 _handler = handler;
87
88 if (isStarted())
89 old_handler.stop();
90
91 }
92 catch(RuntimeException e)
93 {
94 throw e;
95 }
96 catch(Exception e)
97 {
98 throw new RuntimeException(e);
99 }
100 }
101
102 /* ------------------------------------------------------------ */
103 /*
104 * @see org.eclipse.thread.AbstractLifeCycle#doStart()
105 */
106 protected void doStart() throws Exception
107 {
108 if (_handler!=null)
109 _handler.start();
110 super.doStart();
111 }
112
113 /* ------------------------------------------------------------ */
114 /*
115 * @see org.eclipse.thread.AbstractLifeCycle#doStop()
116 */
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 public void setServer(Server server)
139 {
140 if (isRunning())
141 throw new IllegalStateException(RUNNING);
142
143 Server old_server=getServer();
144
145 super.setServer(server);
146
147 Handler h=getHandler();
148 if (h!=null)
149 h.setServer(server);
150
151 if (server!=null && server!=old_server)
152 server.getContainer().update(this, null,_handler, "handler");
153 }
154
155
156 /* ------------------------------------------------------------ */
157 protected Object expandChildren(Object list, Class byClass)
158 {
159 return expandHandler(_handler,list,byClass);
160 }
161
162
163 }