libjava/classpath/javax/management/MBeanNotificationInfo.java

   1 /* MBeanNotificationInfo.java -- Information about a bean's notification.
   2    Copyright (C) 2006 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package javax.management;
  39
  40 import java.util.Arrays;
  41
  42 /**
  43  * <p>
  44  * Describes the notifications emitted by a management bean.
  45  * An instance of this class is specific to notifications
  46  * involving a particular type of object.  A new instance
  47  * should be created for each Java class used for notifications,
  48  * and the Java class name forms the name of the instance.
  49  * Each instance lists a number of notification types; these
  50  * are not types in the sense of different Java classes, but
  51  * instead form the names of notifications following the same
  52  * syntax as Java property and package names.
  53  * </p>
  54  * <p>
  55  * For instance, a management bean may emit two notifications
  56  * containing {@link java.lang.String} objects.  Both would be described
  57  * using one instance of this class, with a member of the array
  58  * returned by {@link #getNotifTypes()} for each one.  If another
  59  * notification containing a {@link java.util.Date} object were to
  60  * be added, this would require a new instance of this class.
  61  * </p>
  62  * <p>
  63  * The information in this class is immutable as standard.
  64  * Of course, subclasses may change this, but this
  65  * behaviour is not recommended.
  66  * </p>
  67  *
  68  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  69  * @since 1.5
  70  */
  71 public class MBeanNotificationInfo
  72   extends MBeanFeatureInfo
  73   implements Cloneable
  74 {
  75
  76   /**
  77    * Compatible with JDK 1.5
  78    */
  79   private static final long serialVersionUID = -3888371564530107064L;
  80
  81   /**
  82    * The types of notification described by this instance.
  83    *
  84    * @serial the types of notification.
  85    */
  86   private String[] types;
  87
  88   /**
  89    * Constructs a new {@link MBeanNotificationInfo} with the
  90    * specified name, description and notification types. The
  91    * notification types array may be <code>null</code> or of
  92    * zero length, in order to indicate the absence of any types.
  93    *
  94    * @param types an array of {@link java.lang.String} objects,
  95    *              containing the names of the notifications emitted
  96    *              of this Java type.  The names use the dot notation
  97    *              familiar from Java property and package names.
  98    * @param name the name of the Java class the notifications described
  99    *             by this object are instances of.
 100    * @param description a description of the data.
 101    * @throws IllegalArgumentException for some reason...
 102    */
 103   public MBeanNotificationInfo(String[] types, String name,
 104                                String description)
 105   {
 106     super(name, description);
 107     this.types = types;
 108   }
 109
 110   /**
 111    * Returns a clone of this instance.  The clone is created
 112    * using just the method provided by {@link java.lang.Object}.
 113    * Thus, the clone is just a shallow clone as returned by
 114    * that method, and does not contain any deeper cloning based
 115    * on the subject of this class.
 116    *
 117    * @return a clone of this instance.
 118    * @see java.lang.Cloneable
 119    */
 120   public Object clone()
 121   {
 122     try
 123       {
 124         return super.clone();
 125       }
 126     catch (CloneNotSupportedException e)
 127       {
 128         /* This shouldn't happen; we implement Cloneable */
 129         throw new IllegalStateException("clone() called on " +
 130                                         "non-cloneable object.");
 131       }
 132   }
 133
 134   /**
 135    * Compares this feature with the supplied object.  This returns
 136    * true iff the object is an instance of {@link
 137    * MBeanNotificationInfo}, {@link Object#equals()} returns true for
 138    * a comparison of both the name and description of this
 139    * notification with that of the specified object, and the two
 140    * notification type arrays contain the same elements in the same
 141    * order (but one may be longer than the other).
 142    *
 143    * @param obj the object to compare.
 144    * @return true if the object is a {@link MBeanNotificationInfo}
 145    *         instance,
 146    *         <code>name.equals(object.getName())</code>,
 147    *         <code>description.equals(object.getDescription())</code>
 148    *         and the corresponding elements of the type arrays are
 149    *         equal.
 150    */
 151   public boolean equals(Object obj)
 152   {
 153     if (obj instanceof MBeanNotificationInfo)
 154       {
 155         if (!(super.equals(obj)))
 156           return false;
 157         MBeanNotificationInfo o = (MBeanNotificationInfo) obj;
 158         String[] oTypes = o.getNotifTypes();
 159         for (int a = 0; a < types.length; ++a)
 160           {
 161             if (a == oTypes.length)
 162               return true;
 163             if (!(types[a].equals(oTypes[a])))
 164               return false;
 165           }
 166         return true;
 167       }
 168     else
 169       return false;
 170   }
 171
 172   /**
 173    * Returns the notification types that the management bean may emit.
 174    * The notification types are strings using the dot notation
 175    * familiar from Java property and package names.  Changing the
 176    * returned array does not affect the values retained by this
 177    * instance.
 178    *
 179    * @return the notification types.
 180    */
 181   public String[] getNotifTypes()
 182   {
 183     return types;
 184   }
 185
 186   /**
 187    * Returns the hashcode of the notification information as the sum
 188    * of the hashcode of the superclass and the hashcode of the types
 189    * array.
 190    *
 191    * @return the hashcode of the notification information.
 192    */
 193   public int hashCode()
 194   {
 195     return super.hashCode() + Arrays.hashCode(types);
 196   }
 197
 198   /**
 199    * <p>
 200    * Returns a textual representation of this instance.  This
 201    * is constructed using the class name
 202    * (<code>javax.management.MBeanNotificationInfo</code>),
 203    * the name and description of the notification and the
 204    * contents of the array of types.
 205    * </p>
 206    * <p>
 207    * As instances of this class are immutable, the return value
 208    * is computed just once for each instance and reused
 209    * throughout its life.
 210    * </p>
 211    *
 212    * @return a @link{java.lang.String} instance representing
 213    *         the instance in textual form.
 214    */
 215   public String toString()
 216   {
 217     if (string == null)
 218       {
 219         super.toString();
 220         string = string.substring(0, string.length() - 1)
 221           + ",types=" + Arrays.toString(types)
 222           + "]";
 223       }
 224     return string;
 225   }
 226
 227 }