/* ===========================================================

 * JFreeChart : a free chart library for the Java(tm) platform

 * ===========================================================

 *

 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.

 *

 * Project Info:  http://www.jfree.org/jfreechart/index.html

 *

 * This library is free software; you can redistribute it and/or modify it under the terms

 * of the GNU Lesser General Public License as published by the Free Software Foundation;

 * either version 2.1 of the License, or (at your option) any later version.

 *

 * This library 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License along with this

 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,

 * Boston, MA 02111-1307, USA.

 *

 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 

 * in the United States and other countries.]

 *

 * ----------------------

 * DefaultKeyedValue.java

 * ----------------------

 * (C) Copyright 2002-2004, by Object Refinery Limited.

 *

 * Original Author:  David Gilbert (for Object Refinery Limited);

 * Contributor(s):   -;

 *

 * $Id: DefaultKeyedValue.java,v 1.1 2004/08/31 15:21:49 mungady Exp $

 *

 * Changes:

 * --------

 * 31-Oct-2002 : Version 1 (DG);

 * 13-Mar-2003 : Added equals(...) method, and implemented Serializable (DG);

 * 18-Aug-2003 : Implemented Cloneable (DG);

 * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.base (DG);

 *

 */



package org.jfree.data;



import java.io.Serializable;





/**

 * A (key, value) pair.

 * <P>

 * This class provides a default implementation of the {@link KeyedValue} interface.

 */

public class DefaultKeyedValue implements KeyedValue, Cloneable, Serializable {



    /** The key. */

    private Comparable key;



    /** The value. */

    private Number value;



    /**

     * Creates a new (key, value) pair.

     *

     * @param key  the key.

     * @param value  the value (<code>null</code> permitted).

     */

    public DefaultKeyedValue(final Comparable key, final Number value) {

        this.key = key;

        this.value = value;

    }



    /**

     * Returns the key.

     *

     * @return The key.

     */

    public Comparable getKey() {

        return this.key;

    }



    /**

     * Returns the value.

     *

     * @return The value.

     */

    public Number getValue() {

        return this.value;

    }



    /**

     * Sets the value.

     *

     * @param value  the value.

     */

    public synchronized void setValue(final Number value) {

        this.value = value;

    }



    /**

     * Tests if this object is equal to another.

     *

     * @param o  the other object.

     *

     * @return A boolean.

     */

    public boolean equals(final Object o) {

        if (this == o) {

            return true;

        }

        if (!(o instanceof DefaultKeyedValue)) {

            return false;

        }



        final DefaultKeyedValue defaultKeyedValue = (DefaultKeyedValue) o;



        if (this.key != null ? !this.key.equals(defaultKeyedValue.key) 

                : defaultKeyedValue.key != null) {

            return false;

        }

        if (this.value != null ? !this.value.equals(defaultKeyedValue.value) 

                : defaultKeyedValue.value != null) {

            return false;

        }



        return true;

    }



    /**

     * Returns a hash code.

     * 

     * @return A hash code.

     */

    public int hashCode() {

        int result;

        result = (this.key != null ? this.key.hashCode() : 0);

        result = 29 * result + (this.value != null ? this.value.hashCode() : 0);

        return result;

    }



    /**

     * Returns a clone.  It is assumed that both the key and value are immutable objects,

     * so only the references are cloned, not the objects themselves.

     * 

     * @return A clone.

     * 

     * @throws CloneNotSupportedException Not thrown by this class, but subclasses (if any) might.

     */

    public Object clone() throws CloneNotSupportedException {

        DefaultKeyedValue clone = (DefaultKeyedValue) super.clone();

        return clone;

    }

}

