-
Notifications
You must be signed in to change notification settings - Fork 1.9k
/
ListenerHolder.java
184 lines (164 loc) · 5.38 KB
/
ListenerHolder.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
//
// ========================================================================
// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under
// the terms of the Eclipse Public License 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0
//
// This Source Code may also be made available under the following
// Secondary Licenses when the conditions for such availability set
// forth in the Eclipse Public License, v. 2.0 are satisfied:
// the Apache License v2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.servlet;
import java.util.EventListener;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.eclipse.jetty.server.handler.ContextHandler;
import org.eclipse.jetty.util.thread.AutoLock;
/**
* ListenerHolder
*
* Specialization of BaseHolder for servlet listeners. This
* allows us to record where the listener originated - web.xml,
* annotation, api etc.
*/
public class ListenerHolder extends BaseHolder<EventListener>
{
private EventListener _listener;
public ListenerHolder()
{
this(Source.EMBEDDED);
}
public ListenerHolder(Source source)
{
super(source);
}
public ListenerHolder(Class<? extends EventListener> listenerClass)
{
super(Source.EMBEDDED);
setHeldClass(listenerClass);
}
public EventListener getListener()
{
return _listener;
}
/**
* Set an explicit instance. In this case,
* just like ServletHolder and FilterHolder,
* the listener will not be introspected for
* annotations like Resource etc.
* @param listener The listener instance
*/
public void setListener(EventListener listener)
{
setInstance(listener);
}
@Override
public void doStart() throws Exception
{
super.doStart();
if (!java.util.EventListener.class.isAssignableFrom(getHeldClass()))
{
String msg = getHeldClass() + " is not a java.util.EventListener";
super.stop();
throw new IllegalStateException(msg);
}
ContextHandler contextHandler = null;
if (getServletHandler() != null)
contextHandler = getServletHandler().getServletContextHandler();
if (contextHandler == null && ContextHandler.getCurrentContext() != null)
contextHandler = ContextHandler.getCurrentContext().getContextHandler();
if (contextHandler == null)
throw new IllegalStateException("No Context");
_listener = getInstance();
if (_listener == null)
{
//create an instance of the listener and decorate it
_listener = createInstance();
_listener = wrap(_listener, WrapFunction.class, WrapFunction::wrapEventListener);
}
contextHandler.addEventListener(_listener);
}
@Override
protected EventListener createInstance() throws Exception
{
try (AutoLock l = lock())
{
EventListener listener = super.createInstance();
if (listener == null)
{
ServletContext ctx = getServletContext();
if (ctx != null)
listener = ctx.createListener(getHeldClass());
}
return listener;
}
}
@Override
public void doStop() throws Exception
{
super.doStop();
if (_listener != null)
{
try
{
ContextHandler contextHandler = ContextHandler.getCurrentContext().getContextHandler();
if (contextHandler != null)
contextHandler.removeEventListener(_listener);
getServletHandler().destroyListener(unwrap(_listener));
}
finally
{
_listener = null;
}
}
}
@Override
public String toString()
{
return super.toString() + ": " + getClassName();
}
/**
* Experimental Wrapper mechanism for Servlet EventListeners.
* <p>
* Beans in {@code ServletContextHandler} or {@code WebAppContext} that implement this interface
* will be called to optionally wrap any newly created Servlet EventListeners before
* they are used for the first time.
* </p>
*/
public interface WrapFunction
{
/**
* Optionally wrap the Servlet EventListener.
*
* @param listener the Servlet EventListener being passed in.
* @return the Servlet EventListener (extend from {@link ListenerHolder.Wrapper}
* if you do wrap the Servlet EventListener)
*/
EventListener wrapEventListener(EventListener listener);
}
public static class Wrapper implements EventListener, Wrapped<EventListener>
{
final EventListener _listener;
public Wrapper(EventListener listener)
{
_listener = listener;
}
@Override
public EventListener getWrapped()
{
return _listener;
}
@Override
public String toString()
{
return String.format("%s:%s", this.getClass().getSimpleName(), _listener.toString());
}
}
}