1 /*
2 * Copyright (c) 2011, 2013, 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 com.sun.management;
27
28 import javax.management.Notification;
29 import javax.management.openmbean.CompositeData;
30 import javax.management.openmbean.CompositeDataView;
31 import javax.management.openmbean.CompositeType;
32 import java.util.Collection;
33 import java.util.Collections;
34 import sun.management.GarbageCollectionNotifInfoCompositeData;
35
36 /**
37 * The information about a garbage collection
38 *
39 * <p>
40 * A garbage collection notification is emitted by {@link GarbageCollectorMXBean}
41 * when the Java virtual machine completes a garbage collection action
42 * The notification emitted will contain the garbage collection notification
43 * information about the status of the memory:
44 * <ul>
45 * <li>The name of the garbage collector used to perform the collection.</li>
46 * <li>The action performed by the garbage collector.</li>
47 * <li>The cause of the garbage collection action.</li>
48 * <li>A {@link GcInfo} object containing some statistics about the GC cycle
49 (start time, end time) and the memory usage before and after
50 the GC cycle.</li>
51 * </ul>
52 *
53 * <p>
54 * A {@link CompositeData CompositeData} representing
55 * the {@code GarbageCollectionNotificationInfo} object
56 * is stored in the
57 * {@linkplain javax.management.Notification#setUserData userdata}
58 * of a {@linkplain javax.management.Notification notification}.
59 * The {@link #from from} method is provided to convert from
60 * a {@code CompositeData} to a {@code GarbageCollectionNotificationInfo}
61 * object. For example:
62 *
63 * <blockquote><pre>
64 * Notification notif;
65 *
66 * // receive the notification emitted by a GarbageCollectorMXBean and set to notif
67 * ...
68 *
69 * String notifType = notif.getType();
70 * if (notifType.equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) {
71 * // retrieve the garbage collection notification information
72 * CompositeData cd = (CompositeData) notif.getUserData();
73 * GarbageCollectionNotificationInfo info = GarbageCollectionNotificationInfo.from(cd);
74 * ....
75 * }
76 * </pre></blockquote>
77 *
78 * <p>
79 * The type of the notification emitted by a {@code GarbageCollectorMXBean} is:
80 * <ul>
81 * <li>A {@linkplain #GARBAGE_COLLECTION_NOTIFICATION garbage collection notification}.
82 * <br>Used by every notification emitted by the garbage collector, the details about
83 * the notification are provided in the {@linkplain #getGcAction action} String
84 * </li>
85 * </ul>
86 **/
87
88 @jdk.Exported
89 public class GarbageCollectionNotificationInfo implements CompositeDataView {
90
91 private final String gcName;
92 private final String gcAction;
93 private final String gcCause;
94 private final GcInfo gcInfo;
95 private final CompositeData cdata;
96
97 /**
98 * Notification type denoting that
99 * the Java virtual machine has completed a garbage collection cycle.
100 * This notification is emitted by a {@link GarbageCollectorMXBean}.
101 * The value of this notification type is
102 * {@code com.sun.management.gc.notification}.
103 */
104 public static final String GARBAGE_COLLECTION_NOTIFICATION =
105 "com.sun.management.gc.notification";
106
107 /**
108 * Constructs a {@code GarbageCollectionNotificationInfo} object.
109 *
110 * @param gcName The name of the garbage collector used to perform the collection
111 * @param gcAction The name of the action performed by the garbage collector
112 * @param gcCause The cause of the garbage collection action
113 * @param gcInfo a GcInfo object providing statistics about the GC cycle
114 */
115 public GarbageCollectionNotificationInfo(String gcName,
116 String gcAction,
117 String gcCause,
118 GcInfo gcInfo) {
119 if (gcName == null) {
120 throw new NullPointerException("Null gcName");
121 }
122 if (gcAction == null) {
123 throw new NullPointerException("Null gcAction");
124 }
125 if (gcCause == null) {
126 throw new NullPointerException("Null gcCause");
127 }
128 this.gcName = gcName;
129 this.gcAction = gcAction;
130 this.gcCause = gcCause;
131 this.gcInfo = gcInfo;
132 this.cdata = new GarbageCollectionNotifInfoCompositeData(this);
133 }
134
135 GarbageCollectionNotificationInfo(CompositeData cd) {
136 GarbageCollectionNotifInfoCompositeData.validateCompositeData(cd);
137
138 this.gcName = GarbageCollectionNotifInfoCompositeData.getGcName(cd);
139 this.gcAction = GarbageCollectionNotifInfoCompositeData.getGcAction(cd);
140 this.gcCause = GarbageCollectionNotifInfoCompositeData.getGcCause(cd);
141 this.gcInfo = GarbageCollectionNotifInfoCompositeData.getGcInfo(cd);
142 this.cdata = cd;
143 }
144
145 /**
146 * Returns the name of the garbage collector used to perform the collection
147 *
148 * @return the name of the garbage collector used to perform the collection
149 */
150 public String getGcName() {
151 return gcName;
152 }
153
154 /**
155 * Returns the action performed by the garbage collector
156 *
157 * @return the action performed by the garbage collector
158 */
159 public String getGcAction() {
160 return gcAction;
161 }
162
163 /**
164 * Returns the cause of the garbage collection
165 *
166 * @return the cause of the garbage collection
167 */
168 public String getGcCause() {
169 return gcCause;
170 }
171
172 /**
173 * Returns the GC information related to the last garbage collection
174 *
175 * @return the GC information related to the
176 * last garbage collection
177 */
178 public GcInfo getGcInfo() {
179 return gcInfo;
180 }
181
182 /**
183 * Returns a {@code GarbageCollectionNotificationInfo} object represented by the
184 * given {@code CompositeData}.
185 * The given {@code CompositeData} must contain
186 * the following attributes:
187 * <blockquote>
188 * <table border>
189 * <tr>
190 * <th align=left>Attribute Name</th>
191 * <th align=left>Type</th>
192 * </tr>
193 * <tr>
194 * <td>gcName</td>
195 * <td>{@code java.lang.String}</td>
196 * </tr>
197 * <tr>
198 * <td>gcAction</td>
199 * <td>{@code java.lang.String}</td>
200 * </tr>
201 * <tr>
202 * <td>gcCause</td>
203 * <td>{@code java.lang.String}</td>
204 * </tr>
205 * <tr>
206 * <td>gcInfo</td>
207 * <td>{@code javax.management.openmbean.CompositeData}</td>
208 * </tr>
209 * </table>
210 * </blockquote>
211 *
212 * @param cd {@code CompositeData} representing a
213 * {@code GarbageCollectionNotificationInfo}
214 *
215 * @throws IllegalArgumentException if {@code cd} does not
216 * represent a {@code GarbaageCollectionNotificationInfo} object.
217 *
218 * @return a {@code GarbageCollectionNotificationInfo} object represented
219 * by {@code cd} if {@code cd} is not {@code null};
220 * {@code null} otherwise.
221 */
222 public static GarbageCollectionNotificationInfo from(CompositeData cd) {
223 if (cd == null) {
224 return null;
225 }
226
227 if (cd instanceof GarbageCollectionNotifInfoCompositeData) {
228 return ((GarbageCollectionNotifInfoCompositeData) cd).getGarbageCollectionNotifInfo();
229 } else {
230 return new GarbageCollectionNotificationInfo(cd);
231 }
232 }
233
234 public CompositeData toCompositeData(CompositeType ct) {
235 return cdata;
236 }
237
238 }