1 //
2 // ========================================================================
3 // Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.server.handler;
20
21 import java.io.IOException;
22 import java.util.List;
23
24 import javax.servlet.ServletException;
25 import javax.servlet.http.HttpServletRequest;
26 import javax.servlet.http.HttpServletResponse;
27
28 import org.eclipse.jetty.server.Handler;
29 import org.eclipse.jetty.server.Request;
30 import org.eclipse.jetty.server.Server;
31 import org.eclipse.jetty.util.annotation.ManagedAttribute;
32 import org.eclipse.jetty.util.annotation.ManagedObject;
33 import org.eclipse.jetty.util.component.LifeCycle;
34
35 /* ------------------------------------------------------------ */
36 /** A <code>HandlerWrapper</code> acts as a {@link Handler} but delegates the {@link Handler#handle handle} method and
37 * {@link LifeCycle life cycle} events to a delegate. This is primarily used to implement the <i>Decorator</i> pattern.
38 *
39 */
40 @ManagedObject("Handler wrapping another Handler")
41 public class HandlerWrapper extends AbstractHandlerContainer
42 {
43 protected Handler _handler;
44
45 /* ------------------------------------------------------------ */
46 /**
47 *
48 */
49 public HandlerWrapper()
50 {
51 }
52
53 /* ------------------------------------------------------------ */
54 /**
55 * @return Returns the handlers.
56 */
57 @ManagedAttribute(value="Wrapped Handler", readonly=true)
58 public Handler getHandler()
59 {
60 return _handler;
61 }
62
63 /* ------------------------------------------------------------ */
64 /**
65 * @return Returns the handlers.
66 */
67 @Override
68 public Handler[] getHandlers()
69 {
70 if (_handler==null)
71 return new Handler[0];
72 return new Handler[] {_handler};
73 }
74
75 /* ------------------------------------------------------------ */
76 /**
77 * @param handler Set the {@link Handler} which should be wrapped.
78 */
79 public void setHandler(Handler handler)
80 {
81 if (isStarted())
82 throw new IllegalStateException(STARTED);
83
84 if (handler!=null)
85 handler.setServer(getServer());
86
87 updateBean(_handler,handler);
88 _handler=handler;
89 }
90
91 /* ------------------------------------------------------------ */
92 @Override
93 public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
94 {
95 if (_handler!=null && isStarted())
96 {
97 _handler.handle(target,baseRequest, request, response);
98 }
99 }
100
101
102 /* ------------------------------------------------------------ */
103 @Override
104 public void setServer(Server server)
105 {
106 if (server==getServer())
107 return;
108
109 if (isStarted())
110 throw new IllegalStateException(STARTED);
111
112 super.setServer(server);
113 Handler h=getHandler();
114 if (h!=null)
115 h.setServer(server);
116 }
117
118
119 /* ------------------------------------------------------------ */
120 @Override
121 protected void expandChildren(List<Handler> list, Class<?> byClass)
122 {
123 expandHandler(_handler,list,byClass);
124 }
125
126 /* ------------------------------------------------------------ */
127 @Override
128 public void destroy()
129 {
130 if (!isStopped())
131 throw new IllegalStateException("!STOPPED");
132 Handler child=getHandler();
133 if (child!=null)
134 {
135 setHandler(null);
136 child.destroy();
137 }
138 super.destroy();
139 }
140
141 }