1 /*
2 * Copyright (c) 1999, 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 javax.management;
27
28 import java.io.IOException;
29 import java.io.InvalidObjectException;
30 import java.io.ObjectInputStream;
31 import java.util.Arrays;
32 import java.util.Objects;
33
34 /**
35 * <p>The {@code MBeanNotificationInfo} class is used to describe the
36 * characteristics of the different notification instances
37 * emitted by an MBean, for a given Java class of notification.
38 * If an MBean emits notifications that can be instances of different Java classes,
39 * then the metadata for that MBean should provide an {@code MBeanNotificationInfo}
40 * object for each of these notification Java classes.</p>
41 *
42 * <p>Instances of this class are immutable. Subclasses may be
43 * mutable but this is not recommended.</p>
44 *
45 * <p>This class extends {@code javax.management.MBeanFeatureInfo}
46 * and thus provides {@code name} and {@code description} fields.
47 * The {@code name} field should be the fully qualified Java class name of
48 * the notification objects described by this class.</p>
49 *
50 * <p>The {@code getNotifTypes} method returns an array of
51 * strings containing the notification types that the MBean may
52 * emit. The notification type is a dot-notation string which
53 * describes what the emitted notification is about, not the Java
54 * class of the notification. A single generic notification class can
55 * be used to send notifications of several types. All of these types
56 * are returned in the string array result of the
57 * {@code getNotifTypes} method.
58 *
59 * @since 1.5
60 */
61 public class MBeanNotificationInfo extends MBeanFeatureInfo implements Cloneable {
62
63 /* Serial version */
64 static final long serialVersionUID = -3888371564530107064L;
65
66 private static final String[] NO_TYPES = new String[0];
67
68 static final MBeanNotificationInfo[] NO_NOTIFICATIONS =
69 new MBeanNotificationInfo[0];
70
71 /**
72 * @serial The different types of the notification.
73 */
74 private String[] types;
75
76 /** @see MBeanInfo#arrayGettersSafe */
77 private final transient boolean arrayGettersSafe;
78
79 /**
80 * Constructs an {@code MBeanNotificationInfo} object.
81 *
82 * @param notifTypes The array of strings (in dot notation)
83 * containing the notification types that the MBean may emit.
84 * This may be null with the same effect as a zero-length array.
85 * @param name The fully qualified Java class name of the
86 * described notifications.
87 * @param description A human readable description of the data.
88 */
89 public MBeanNotificationInfo(String[] notifTypes,
90 String name,
91 String description) {
92 this(notifTypes, name, description, null);
93 }
94
95 /**
96 * Constructs an {@code MBeanNotificationInfo} object.
97 *
98 * @param notifTypes The array of strings (in dot notation)
99 * containing the notification types that the MBean may emit.
100 * This may be null with the same effect as a zero-length array.
101 * @param name The fully qualified Java class name of the
102 * described notifications.
103 * @param description A human readable description of the data.
104 * @param descriptor The descriptor for the notifications. This may be null
105 * which is equivalent to an empty descriptor.
106 *
107 * @since 1.6
108 */
109 public MBeanNotificationInfo(String[] notifTypes,
110 String name,
111 String description,
112 Descriptor descriptor) {
113 super(name, description, descriptor);
114
115 /* We do not validate the notifTypes, since the spec just says
116 they are dot-separated, not that they must look like Java
117 classes. E.g. the spec doesn't forbid "sun.prob.25" as a
118 notifType, though it doesn't explicitly allow it
119 either. */
120
121 this.types = (notifTypes != null && notifTypes.length > 0) ?
122 notifTypes.clone() : NO_TYPES;
123 this.arrayGettersSafe =
124 MBeanInfo.arrayGettersSafe(this.getClass(),
125 MBeanNotificationInfo.class);
126 }
127
128
129 /**
130 * Returns a shallow clone of this instance.
131 * The clone is obtained by simply calling {@code super.clone()},
132 * thus calling the default native shallow cloning mechanism
133 * implemented by {@code Object.clone()}.
134 * No deeper cloning of any internal field is made.
135 */
136 public Object clone () {
137 try {
138 return super.clone() ;
139 } catch (CloneNotSupportedException e) {
140 // should not happen as this class is cloneable
141 return null;
142 }
143 }
144
145
146 /**
147 * Returns the array of strings (in dot notation) containing the
148 * notification types that the MBean may emit.
149 *
150 * @return the array of strings. Changing the returned array has no
151 * effect on this MBeanNotificationInfo.
152 */
153 public String[] getNotifTypes() {
154 if (types.length == 0)
155 return NO_TYPES;
156 else
157 return types.clone();
158 }
159
160 private String[] fastGetNotifTypes() {
161 if (arrayGettersSafe)
162 return types;
163 else
164 return getNotifTypes();
165 }
166
167 public String toString() {
168 return
169 getClass().getName() + "[" +
170 "description=" + getDescription() + ", " +
171 "name=" + getName() + ", " +
172 "notifTypes=" + Arrays.asList(fastGetNotifTypes()) + ", " +
173 "descriptor=" + getDescriptor() +
174 "]";
175 }
176
177 /**
178 * Compare this MBeanNotificationInfo to another.
179 *
180 * @param o the object to compare to.
181 *
182 * @return true if and only if {@code o} is an MBeanNotificationInfo
183 * such that its {@link #getName()}, {@link #getDescription()},
184 * {@link #getDescriptor()},
185 * and {@link #getNotifTypes()} values are equal (not necessarily
186 * identical) to those of this MBeanNotificationInfo. Two
187 * notification type arrays are equal if their corresponding
188 * elements are equal. They are not equal if they have the same
189 * elements but in a different order.
190 */
191 public boolean equals(Object o) {
192 if (o == this)
193 return true;
194 if (!(o instanceof MBeanNotificationInfo))
195 return false;
196 MBeanNotificationInfo p = (MBeanNotificationInfo) o;
197 return (Objects.equals(p.getName(), getName()) &&
198 Objects.equals(p.getDescription(), getDescription()) &&
199 Objects.equals(p.getDescriptor(), getDescriptor()) &&
200 Arrays.equals(p.fastGetNotifTypes(), fastGetNotifTypes()));
201 }
202
203 public int hashCode() {
204 int hash = getName().hashCode();
205 for (int i = 0; i < types.length; i++)
206 hash ^= types[i].hashCode();
207 return hash;
208 }
209
210 private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
211 ObjectInputStream.GetField gf = ois.readFields();
212 String[] t = (String[])gf.get("types", null);
213
214 types = (t != null && t.length != 0) ? t.clone() : NO_TYPES;
215 }
216 }