1 /*
   2  * Copyright (c) 2003, 2010, 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 sun.jvmstat.monitor;
  27 
  28 /**
  29  * Provides a typesafe enumeration for describing units of measurement
  30  * attribute for instrumentation objects.
  31  *
  32  * @author   Brian Doherty
  33  */
  34 public class Units implements java.io.Serializable {
  35 
  36     /* The enumeration values for this typesafe enumeration must be
  37      * kept in synchronization with the Units enum in the perfData.hpp file
  38      * in the HotSpot source base.
  39      */
  40 
  41     private static final int NUNITS=8;
  42 
  43     private static Units[] map = new Units[NUNITS];
  44 
  45     private final String name;
  46     private final int value;
  47 
  48     /**
  49      * An Invalid Units value.
  50      */
  51     public static final Units INVALID = new Units("Invalid", 0);
  52 
  53     /**
  54      * Units attribute representing unit-less quantities.
  55      */
  56     public static final Units NONE = new Units("None", 1);
  57 
  58     /**
  59      * Units attribute representing Bytes.
  60      */
  61     public static final Units BYTES = new Units("Bytes", 2);
  62 
  63     /**
  64      * Units attribute representing Ticks.
  65      */
  66     public static final Units TICKS = new Units("Ticks", 3);
  67 
  68     /**
  69      * Units attribute representing a count of events.
  70      */
  71     public static final Units EVENTS = new Units("Events", 4);
  72 
  73     /**
  74      * Units attribute representing String data. Although not really
  75      * a unit of measure, this Units value serves to distinguish String
  76      * instrumentation objects from instrumentation objects of other types.
  77      */
  78     public static final Units STRING = new Units("String", 5);
  79 
  80     /**
  81      * Units attribute representing Hertz (frequency).
  82      */
  83     public static final Units HERTZ = new Units("Hertz", 6);
  84 
  85     /**
  86      * Returns a string describing this Unit of measurement attribute
  87      *
  88      * @return String - a descriptive string for this enum.
  89      */
  90     public String toString() {
  91         return name;
  92     }
  93 
  94     /**
  95      * Returns the integer representation of this Units attribute
  96      *
  97      * @return int - an integer representation of this Units attribute.
  98      */
  99     public int intValue() {
 100         return value;
 101     }
 102 
 103     /**
 104      * Maps an integer value to its corresponding Units attribute.
 105      * If the integer value does not have a corresponding Units enum
 106      * value, then {@link Units#INVALID} is returned.
 107      *
 108      * @param value an integer representation of counter Units
 109      * @return Units - the Units object for the given <code>value</code>
 110      *                 or {@link Units#INVALID} if out of range.
 111      */
 112     public static Units toUnits(int value) {
 113 
 114         if (value < 0 || value >= map.length || map[value] == null) {
 115             return INVALID;
 116         }
 117 
 118         return map[value];
 119     }
 120 
 121     private Units(String name, int value) {
 122         this.name = name;
 123         this.value = value;
 124         map[value] = this;
 125     }
 126 
 127     private static final long serialVersionUID = 6992337162326171013L;
 128 }