1 /*
2 * Copyright (c) 1999, 2006, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.management;
27
28
29 import java.util.List;
30 import java.util.Vector;
31
32 /**
33 * Provides an implementation of the {@link javax.management.NotificationFilter} interface.
34 * The filtering is performed on the notification type attribute.
35 * <P>
36 * Manages a list of enabled notification types.
37 * A method allows users to enable/disable as many notification types as required.
38 * <P>
39 * Then, before sending a notification to a listener registered with a filter,
40 * the notification broadcaster compares this notification type with all notification types
41 * enabled by the filter. The notification will be sent to the listener
42 * only if its filter enables this notification type.
43 * <P>
44 * Example:
45 * <BLOCKQUOTE>
46 * <PRE>
47 * NotificationFilterSupport myFilter = new NotificationFilterSupport();
48 * myFilter.enableType("my_example.my_type");
49 * myBroadcaster.addListener(myListener, myFilter, null);
50 * </PRE>
51 * </BLOCKQUOTE>
52 * The listener <CODE>myListener</CODE> will only receive notifications the type of which equals/starts with "my_example.my_type".
53 *
54 * @see javax.management.NotificationBroadcaster#addNotificationListener
55 *
56 * @since 1.5
57 */
58 public class NotificationFilterSupport implements NotificationFilter {
59
60 /* Serial version */
61 private static final long serialVersionUID = 6579080007561786969L;
62
63 /**
64 * @serial {@link Vector} that contains the enabled notification types.
65 * The default value is an empty vector.
66 */
67 private List<String> enabledTypes = new Vector<String>();
68
69
70 /**
71 * Invoked before sending the specified notification to the listener.
72 * <BR>This filter compares the type of the specified notification with each enabled type.
73 * If the notification type matches one of the enabled types,
74 * the notification should be sent to the listener and this method returns <CODE>true</CODE>.
75 *
76 * @param notification The notification to be sent.
77 * @return <CODE>true</CODE> if the notification should be sent to the listener, <CODE>false</CODE> otherwise.
78 */
79 public synchronized boolean isNotificationEnabled(Notification notification) {
80
81 String type = notification.getType();
82
83 if (type == null) {
84 return false;
85 }
86 try {
87 for (String prefix : enabledTypes) {
88 if (type.startsWith(prefix)) {
89 return true;
90 }
91 }
92 } catch (java.lang.NullPointerException e) {
93 // Should never occurs...
94 return false;
95 }
96 return false;
97 }
98
99 /**
100 * Enables all the notifications the type of which starts with the specified prefix
101 * to be sent to the listener.
102 * <BR>If the specified prefix is already in the list of enabled notification types,
103 * this method has no effect.
104 * <P>
105 * Example:
106 * <BLOCKQUOTE>
107 * <PRE>
108 * // Enables all notifications the type of which starts with "my_example" to be sent.
109 * myFilter.enableType("my_example");
110 * // Enables all notifications the type of which is "my_example.my_type" to be sent.
111 * myFilter.enableType("my_example.my_type");
112 * </PRE>
113 * </BLOCKQUOTE>
114 *
115 * Note that:
116 * <BLOCKQUOTE><CODE>
117 * myFilter.enableType("my_example.*");
118 * </CODE></BLOCKQUOTE>
119 * will no match any notification type.
120 *
121 * @param prefix The prefix.
122 * @exception java.lang.IllegalArgumentException The prefix parameter is null.
123 */
124 public synchronized void enableType(String prefix)
125 throws IllegalArgumentException {
126
127 if (prefix == null) {
128 throw new IllegalArgumentException("The prefix cannot be null.");
129 }
130 if (!enabledTypes.contains(prefix)) {
131 enabledTypes.add(prefix);
132 }
133 }
134
135 /**
136 * Removes the given prefix from the prefix list.
137 * <BR>If the specified prefix is not in the list of enabled notification types,
138 * this method has no effect.
139 *
140 * @param prefix The prefix.
141 */
142 public synchronized void disableType(String prefix) {
143 enabledTypes.remove(prefix);
144 }
145
146 /**
147 * Disables all notification types.
148 */
149 public synchronized void disableAllTypes() {
150 enabledTypes.clear();
151 }
152
153
154 /**
155 * Gets all the enabled notification types for this filter.
156 *
157 * @return The list containing all the enabled notification types.
158 */
159 public synchronized Vector<String> getEnabledTypes() {
160 return (Vector<String>)enabledTypes;
161 }
162
163 }