Java example source code file (Units.java)

This example Java source code file (Units.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bytes, events, hertz, invalid, none, nunits\=8, string, ticks, units

The Units.java Java example source code

/*
 * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.management.counter;

/**
 * Provides a typesafe enumeration for describing units of measurement
 * attribute for instrumentation objects.
 *
 * @author   Brian Doherty
 */
public class Units implements java.io.Serializable {

    /* The enumeration values for this typesafe enumeration must be
     * kept in synchronization with the Units enum in the perfData.hpp file
     * in the HotSpot source base.
     */

    private static final int NUNITS=8;

    private static Units[] map = new Units[NUNITS];

    private final String name;
    private final int value;

    /**
     * An Invalid Units value.
     */
    public static final Units INVALID = new Units("Invalid", 0);

    /**
     * Units attribute representing unit-less quantities.
     */
    public static final Units NONE = new Units("None", 1);

    /**
     * Units attribute representing Bytes.
     */
    public static final Units BYTES = new Units("Bytes", 2);

    /**
     * Units attribute representing Ticks.
     */
    public static final Units TICKS = new Units("Ticks", 3);

    /**
     * Units attribute representing a count of events.
     */
    public static final Units EVENTS = new Units("Events", 4);

    /**
     * Units attribute representing String data. Although not really
     * a unit of measure, this Units value serves to distinguish String
     * instrumentation objects from instrumentation objects of other types.
     */
    public static final Units STRING = new Units("String", 5);

    /**
     * Units attribute representing Hertz (frequency).
     */
    public static final Units HERTZ = new Units("Hertz", 6);

    /**
     * Returns a string describing this Unit of measurement attribute
     *
     * @return String - a descriptive string for this enum.
     */
    public String toString() {
        return name;
    }

    /**
     * Returns the integer representation of this Units attribute
     *
     * @return int - an integer representation of this Units attribute.
     */
    public int intValue() {
        return value;
    }

    /**
     * Maps an integer value to its corresponding Units attribute.
     * If the integer value does not have a corresponding Units enum
     * value, then {@link Units#INVALID} is returned.
     *
     * @param value an integer representation of counter Units
     * @return Units - the Units object for the given <code>value
     *                 or {@link Units#INVALID} if out of range.
     */
    public static Units toUnits(int value) {

        if (value < 0 || value >= map.length || map[value] == null) {
            return INVALID;
        }

        return map[value];
    }

    private Units(String name, int value) {
        this.name = name;
        this.value = value;
        map[value] = this;
    }

    private static final long serialVersionUID = 6992337162326171013L;
}