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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</CODE> 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</CODE>
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</CODE>
46   * and thus provides <CODE>name</CODE> and <CODE>description</CODE> fields.
47   * The <CODE>name</CODE> 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</CODE> 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</CODE> 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</CODE> 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</CODE> 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 <tt>super.clone()</tt>,
132      * thus calling the default native shallow cloning mechanism
133      * implemented by <tt>Object.clone()</tt>.
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</code> 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 }