1 //
2 // ========================================================================
3 // Copyright (c) 1995-2015 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.http.HttpStatus;
29 import org.eclipse.jetty.server.Handler;
30 import org.eclipse.jetty.server.Request;
31 import org.eclipse.jetty.server.Server;
32 import org.eclipse.jetty.util.annotation.ManagedAttribute;
33 import org.eclipse.jetty.util.annotation.ManagedObject;
34 import org.eclipse.jetty.util.component.LifeCycle;
35
36 /* ------------------------------------------------------------ */
37 /** A <code>HandlerWrapper</code> acts as a {@link Handler} but delegates the {@link Handler#handle handle} method and
38 * {@link LifeCycle life cycle} events to a delegate. This is primarily used to implement the <i>Decorator</i> pattern.
39 *
40 */
41 @ManagedObject("Handler wrapping another Handler")
42 public class HandlerWrapper extends AbstractHandlerContainer
43 {
44 protected Handler _handler;
45
46 /* ------------------------------------------------------------ */
47 /**
48 *
49 */
50 public HandlerWrapper()
51 {
52 }
53
54 /* ------------------------------------------------------------ */
55 /**
56 * @return Returns the handlers.
57 */
58 @ManagedAttribute(value="Wrapped Handler", readonly=true)
59 public Handler getHandler()
60 {
61 return _handler;
62 }
63
64 /* ------------------------------------------------------------ */
65 /**
66 * @return Returns the handlers.
67 */
68 @Override
69 public Handler[] getHandlers()
70 {
71 if (_handler==null)
72 return new Handler[0];
73 return new Handler[] {_handler};
74 }
75
76 /* ------------------------------------------------------------ */
77 /**
78 * @param handler Set the {@link Handler} which should be wrapped.
79 */
80 public void setHandler(Handler handler)
81 {
82 if (isStarted())
83 throw new IllegalStateException(STARTED);
84
85 if (handler!=null)
86 handler.setServer(getServer());
87
88 Handler old=_handler;
89 _handler=handler;
90 updateBean(old,_handler,true);
91 }
92
93 /* ------------------------------------------------------------ */
94 /**
95 * Replace the current handler with another HandlerWrapper
96 * linked to the current handler.
97 * <p>
98 * This is equivalent to:
99 * <pre>
100 * wrapper.setHandler(getHandler());
101 * setHandler(wrapper);
102 * </pre>
103 * @param wrapper the wrapper to insert
104 */
105 public void insertHandler(HandlerWrapper wrapper)
106 {
107 if (wrapper==null || wrapper.getHandler()!=null)
108 throw new IllegalArgumentException();
109 wrapper.setHandler(getHandler());
110 setHandler(wrapper);
111 }
112
113 /* ------------------------------------------------------------ */
114 @Override
115 public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
116 {
117 Handler handler=_handler;
118 if (handler!=null)
119 handler.handle(target,baseRequest, request, response);
120 }
121
122 /* ------------------------------------------------------------ */
123 @Override
124 protected void expandChildren(List<Handler> list, Class<?> byClass)
125 {
126 expandHandler(_handler,list,byClass);
127 }
128
129 /* ------------------------------------------------------------ */
130 @Override
131 public void destroy()
132 {
133 if (!isStopped())
134 throw new IllegalStateException("!STOPPED");
135 Handler child=getHandler();
136 if (child!=null)
137 {
138 setHandler(null);
139 child.destroy();
140 }
141 super.destroy();
142 }
143
144 }