Counter.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility;

import java.io.Serializable;

/**
 * This class can be used wherever a mutable integer object is needed.
 * It is a cross between an int and an Integer. It can be stored in a standard
 * container (e.g. Collection) but can be modified.
 */
public final class Counter
    implements Cloneable, Serializable
{
    private int count = 0;

    private static final long serialVersionUID = 1L;


    /**
     * Construct a counter with the specified initial value.
     */
    public Counter(int count) {
        super();
        this.count = count;
    }

    /**
     * Construct a counter with an initial value of zero.
     */
    public Counter() {
        this(0);
    }

    /**
     * Return the current count of the counter.
     */
    public synchronized int count() {
        return this.count;
    }

    /**
     * Increment and return the current count of the counter.
     */
    public synchronized int increment() {
        return ++this.count;
    }

    /**
     * Increment and return the current count of the counter.
     */
    public synchronized int increment(int increment) {
        return this.count += increment;
    }

    /**
     * Derement and return the current count of the counter.
     */
    public synchronized int decrement() {
        return --this.count;
    }

    /**
     * Derement and return the current count of the counter.
     */
    public synchronized int decrement(int decrement) {
        return this.count -= decrement;
    }

    /**
     * @see Object#equals(Object)
     */
    public synchronized boolean equals(Object o) {
        if ( ! (o instanceof Counter)) {
            return false;
        }
        return this.count == ((Counter) o).count;
    }

    /**
     * @see Object#hashCode()
     */
    public synchronized int hashCode() {
        return this.count;
    }

    /**
     * @see Object#clone()
     */
    public synchronized Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException ex) {
            throw new InternalError();
        }
    }

    /**
     * @see Object#toString()
     */
    public synchronized String toString() {
        StringBuffer sb = new StringBuffer();
        sb.append(ClassTools.shortClassNameForObject(this));
        sb.append('(');
        sb.append(this.count);
        sb.append(')');
        return sb.toString();
    }

}