1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18
19 package org.apache.catalina.util;
20
21
22 import org.apache.catalina.Lifecycle;
23 import org.apache.catalina.LifecycleEvent;
24 import org.apache.catalina.LifecycleListener;
25
26
27 /**
28 * Support class to assist in firing LifecycleEvent notifications to
29 * registered LifecycleListeners.
30 *
31 * @author Craig R. McClanahan
32 * @version $Id: LifecycleSupport.java 510482 2007-02-22 12:34:36Z remm $
33 */
34
35 public final class LifecycleSupport {
36
37
38 // ----------------------------------------------------------- Constructors
39
40
41 /**
42 * Construct a new LifecycleSupport object associated with the specified
43 * Lifecycle component.
44 *
45 * @param lifecycle The Lifecycle component that will be the source
46 * of events that we fire
47 */
48 public LifecycleSupport(Lifecycle lifecycle) {
49
50 super();
51 this.lifecycle = lifecycle;
52
53 }
54
55
56 // ----------------------------------------------------- Instance Variables
57
58
59 /**
60 * The source component for lifecycle events that we will fire.
61 */
62 private Lifecycle lifecycle = null;
63
64
65 /**
66 * The set of registered LifecycleListeners for event notifications.
67 */
68 private LifecycleListener listeners[] = new LifecycleListener[0];
69
70
71 // --------------------------------------------------------- Public Methods
72
73
74 /**
75 * Add a lifecycle event listener to this component.
76 *
77 * @param listener The listener to add
78 */
79 public void addLifecycleListener(LifecycleListener listener) {
80
81 synchronized (listeners) {
82 LifecycleListener results[] =
83 new LifecycleListener[listeners.length + 1];
84 for (int i = 0; i < listeners.length; i++)
85 results[i] = listeners[i];
86 results[listeners.length] = listener;
87 listeners = results;
88 }
89
90 }
91
92
93 /**
94 * Get the lifecycle listeners associated with this lifecycle. If this
95 * Lifecycle has no listeners registered, a zero-length array is returned.
96 */
97 public LifecycleListener[] findLifecycleListeners() {
98
99 return listeners;
100
101 }
102
103
104 /**
105 * Notify all lifecycle event listeners that a particular event has
106 * occurred for this Container. The default implementation performs
107 * this notification synchronously using the calling thread.
108 *
109 * @param type Event type
110 * @param data Event data
111 */
112 public void fireLifecycleEvent(String type, Object data) {
113
114 LifecycleEvent event = new LifecycleEvent(lifecycle, type, data);
115 LifecycleListener interested[] = listeners;
116 for (int i = 0; i < interested.length; i++)
117 interested[i].lifecycleEvent(event);
118
119 }
120
121
122 /**
123 * Remove a lifecycle event listener from this component.
124 *
125 * @param listener The listener to remove
126 */
127 public void removeLifecycleListener(LifecycleListener listener) {
128
129 synchronized (listeners) {
130 int n = -1;
131 for (int i = 0; i < listeners.length; i++) {
132 if (listeners[i] == listener) {
133 n = i;
134 break;
135 }
136 }
137 if (n < 0)
138 return;
139 LifecycleListener results[] =
140 new LifecycleListener[listeners.length - 1];
141 int j = 0;
142 for (int i = 0; i < listeners.length; i++) {
143 if (i != n)
144 results[j++] = listeners[i];
145 }
146 listeners = results;
147 }
148
149 }
150
151
152 }
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