/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ----------------
 * KeyedObject.java
 * ----------------
 * (C) Copyright 2003-2005, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: KeyedObject.java,v 1.5.2.1 2005/10/25 21:29:13 mungady Exp $
 *
 * Changes:
 * --------
 * 05-Feb-2003 : Version 1 (DG);
 * 27-Jan-2003 : Implemented Cloneable and Serializable, and added an equals()
 *               method (DG);
 *
 */

package org.jfree.data;

import java.io.Serializable;

import org.jfree.util.ObjectUtilities;
import org.jfree.util.PublicCloneable;

/**
 * A (key, object) pair.
 */
public class KeyedObject implements Cloneable, PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 2677930479256885863L;
    
    /** The key. */
    private Comparable key;

    /** The object. */
    private Object object;

    /**
     * Creates a new (key, object) pair.
     *
     * @param key  the key.
     * @param object  the object (<code>null</code> permitted).
     */
    public KeyedObject(Comparable key, Object object) {
        this.key = key;
        this.object = object;
    }

    /**
     * Returns the key.
     *
     * @return The key.
     */
    public Comparable getKey() {
        return this.key;
    }

    /**
     * Returns the object.
     *
     * @return The object (possibly <code>null</code>).
     */
    public Object getObject() {
        return this.object;
    }

    /**
     * Sets the object.
     *
     * @param object  the object (<code>null</code> permitted).
     */
    public void setObject(Object object) {
        this.object = object;
    }
    
    /**
     * Returns a clone of this object.  It is assumed that the key is an 
     * immutable object, so it is not deep-cloned.  The object is deep-cloned 
     * if it implements {@link PublicCloneable}, otherwise a shallow clone is 
     * made.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException if there is a problem cloning.
     */
    public Object clone() throws CloneNotSupportedException {
        KeyedObject clone = (KeyedObject) super.clone();
        if (this.object instanceof PublicCloneable) {
            PublicCloneable pc = (PublicCloneable) this.object;
            clone.object = pc.clone();
        }
        return clone;      
    }
    
    /**
     * Tests if this object is equal to another.
     *
     * @param obj  the other object.
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {

        if (obj == this) {
            return true;
        }

        if (!(obj instanceof KeyedObject)) {
            return false;
        }
        KeyedObject that = (KeyedObject) obj;
        if (!ObjectUtilities.equal(this.key, that.key)) {
            return false;
        }

        if (!ObjectUtilities.equal(this.object, that.object)) {
            return false;
        }

        return true;
    }
    
}
