/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2007, 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.]
 *
 * -----------------
 * XYCoordinate.java
 * -----------------
 * (C) Copyright 2007, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: XYCoordinate.java,v 1.1.2.2 2007/03/09 16:15:15 mungady Exp $
 *
 * Changes
 * -------
 * 30-Jan-2007 : Version 1 (DG);
 *
 */

package org.jfree.experimental.data.xy;

import java.io.Serializable;

/**
 * Represents an (x, y) coordinate.
 */
public class XYCoordinate implements Comparable, Serializable {

    /** The x-coordinate. */
    private double x;
    
    /** The y-coordinate. */
    private double y;
    
    /**
     * Creates a new coordinate for the point (0.0, 0.0).
     */
    public XYCoordinate() {
        this(0.0, 0.0);
    }
    
    /**
     * Creates a new coordinate for the point (x, y).
     * 
     * @param x  the x-coordinate.
     * @param y  the y-coordinate.
     */
    public XYCoordinate(double x, double y) {
        this.x = x;
        this.y = y;
    }
    
    /**
     * Returns the x-coordinate.
     * 
     * @return The x-coordinate.
     */
    public double getX() {
        return this.x;
    }
    
    /**
     * Returns the y-coordinate.
     * 
     * @return The y-coordinate.
     */
    public double getY() {
        return this.y;
    }

    /**
     * Tests this coordinate for equality with an arbitrary object.
     * 
     * @param obj  the object (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof XYCoordinate)) {
            return false;
        }
        XYCoordinate that = (XYCoordinate) obj;
        if (this.x != that.x) {
            return false;
        }
        if (this.y != that.y) {
            return false;
        }
        return true;
    }

    /**
     * Returns a hash code for this instance.
     * 
     * @return A hash code.
     */
    public int hashCode() {
        int result = 193;
        long temp = Double.doubleToLongBits(this.x);
        result = 37 * result + (int) (temp ^ (temp >>> 32));
        temp = Double.doubleToLongBits(this.y);
        result = 37 * result + (int) (temp ^ (temp >>> 32));
        return result;
    }

    /**
     * Returns a string representation of this instance, primarily for 
     * debugging purposes.
     * 
     * @return A string.
     */
    public String toString() {
        return "(" + this.x + ", " + this.y + ")";
    }

    /**
     * Compares this instance against an arbitrary object. 
     * 
     * @param obj  the object (<code>null</code> not permitted).
     * 
     * @return An integer indicating the relative order of the items.
     */
    public int compareTo(Object obj) {
        if (!(obj instanceof XYCoordinate)) {
            throw new IllegalArgumentException("Incomparable object.");
        }
        XYCoordinate that = (XYCoordinate) obj;
        if (this.x > that.x) {
            return 1;
        }
        else if (this.x < that.x) {
            return -1;
        }
        else {
            if (this.y > that.y) {
                return 1;
            }
            else if (this.y < that.y) {
                return -1;
            }
        }
        return 0;
    }
    
}
