libjava/classpath/javax/management/MBeanFeatureInfo.java

   1 /* MBeanFeatureInfo.java -- Information about a bean feature.
   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.io.Serializable;
  41
  42 /**
  43  * A general superclass for the description of features
  44  * of management beans.  This allows the user to access
  45  * the feature dynamically, without knowing the details
  46  * beforehand.  The information is immutable as standard.
  47  * Of course, subclasses may change this, but this
  48  * behaviour is not recommended.
  49  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
  50  * @since 1.5
  51  */
  52 public class MBeanFeatureInfo
  53   implements Serializable
  54 {
  55
  56   /**
  57    * Compatible with JDK 1.5
  58    */
  59   private static final long serialVersionUID = 3952882688968447265L;
  60
  61   /**
  62    * A description of the feature in human-readable form.
  63    * Subclasses should access this via the {@link #getDescription()}
  64    * function rather than using the value directly.
  65    *
  66    * @serial a description of the feature.
  67    */
  68   protected String description;
  69
  70   /**
  71    * The name of the feature.  Subclasses should access this
  72    * via the {@link #getName()} function rather than using the
  73    * value directly.
  74    *
  75    * @serial the name of the feature.
  76    */
  77   protected String name;
  78
  79   /**
  80    * The <code>toString()</code> result of this instance.
  81    */
  82   protected transient String string;
  83
  84   /**
  85    * Constructs a new {@link MBeanFeatureInfo} with the specified
  86    * name and description.
  87    *
  88    * @param name the name of the management bean feature.
  89    * @param description the description of the feature.
  90    */
  91   public MBeanFeatureInfo(String name, String description)
  92   {
  93     this.name = name;
  94     this.description = description;
  95   }
  96
  97   /**
  98    * Compares this feature with the supplied object.  This
  99    * returns true iff the object is an instance of
 100    * {@link MBeanFeatureInfo} and {@link Object#equals()}
 101    * returns true for a comparison of both the name and
 102    * description of this feature with that of the specified
 103    * object.
 104    *
 105    * @param obj the object to compare.
 106    * @return true if the object is a {@link MBeanFeatureInfo}
 107    *         instance,
 108    *         <code>name.equals(object.getName())</code> and
 109    *         <code>description.equals(object.getDescription</code>.
 110    */
 111   public boolean equals(Object obj)
 112   {
 113     if (obj instanceof MBeanFeatureInfo)
 114       {
 115         MBeanFeatureInfo o = (MBeanFeatureInfo) obj;
 116         return ((name == null ?
 117                  o.getName() == null :
 118                  name.equals(o.getName())) &&
 119                 (description == null ?
 120                  o.getDescription() == null :
 121                  description.equals(o.getDescription())));
 122       }
 123     else
 124       return false;
 125   }
 126
 127   /**
 128    * Returns a description of this feature.
 129    *
 130    * @return a human-readable description.
 131    */
 132   public String getDescription()
 133   {
 134     return description;
 135   }
 136
 137   /**
 138    * Returns the name of this feature.
 139    *
 140    * @return the name of the feature.
 141    */
 142   public String getName()
 143   {
 144     return name;
 145   }
 146
 147   /**
 148    * Returns the hashcode of the feature as
 149    * the sum of the hashcodes of its name
 150    * and description.
 151    *
 152    * @return the hashcode of this feature.
 153    */
 154   public int hashCode()
 155   {
 156     return (name == null ? -1 : name.hashCode())
 157       + (description == null ? -1 : description.hashCode());
 158   }
 159
 160   /**
 161    * <p>
 162    * Returns a textual representation of this instance.  This
 163    * is constructed using the class name
 164    * (<code>javax.management.MBeanFeatureInfo</code>) and
 165    * the name and description of the feature.
 166    * </p>
 167    * <p>
 168    * As instances of this class are immutable, the return value
 169    * is computed just once for each instance and reused
 170    * throughout its life.
 171    * </p>
 172    *
 173    * @return a @link{java.lang.String} instance representing
 174    *         the instance in textual form.
 175    */
 176   public String toString()
 177   {
 178     if (string == null)
 179       string = getClass().getName()
 180         + "[name=" + name
 181         + ",desc=" + description
 182         + "]";
 183     return string;
 184   }
 185
 186 }