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

 * 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.]

 *

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

 * AxisLocation.java

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

 * (C) Copyright 2003, 2004, by Object Refinery Limited.

 *

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

 * Contributor(s):   -;

 *

 * $Id: AxisLocation.java,v 1.1 2004/08/31 14:30:22 mungady Exp $

 *

 * Changes:

 * --------

 * 02-May-2003 : Version 1 (DG);

 * 03-Jul-2003 : Added isTopOrBottom() and isLeftOrRight() methods (DG);

 * 13-Aug-2003 : Fixed readResolve() bug (id=788202) (DG);

 * 24-Mar-2004 : Added getOpposite() method (DG);

 *

 */



package org.jfree.chart.axis;



import java.io.ObjectStreamException;

import java.io.Serializable;



/**

 * Used to indicate the location of an axis on a 2D plot, prior to knowing the orientation of

 * the plot.

 */

public final class AxisLocation implements Serializable {



    /** Axis at the top or left. */

    public static final AxisLocation TOP_OR_LEFT = new AxisLocation("AxisLocation.TOP_OR_LEFT");



    /** Axis at the top or right. */

    public static final AxisLocation TOP_OR_RIGHT = new AxisLocation("AxisLocation.TOP_OR_RIGHT");

    

    /** Axis at the bottom or left. */

    public static final AxisLocation BOTTOM_OR_LEFT = new AxisLocation(

        "AxisLocation.BOTTOM_OR_LEFT"

    );

        

    /** Axis at the bottom or right. */

    public static final AxisLocation BOTTOM_OR_RIGHT = new AxisLocation(

        "AxisLocation.BOTTOM_OR_RIGHT"

    );

    

    /** The name. */

    private String name;



    /**

     * Private constructor.

     *

     * @param name  the name.

     */

    private AxisLocation(String name) {

        this.name = name;

    }



    /**

     * Returns a string representing the object.

     *

     * @return The string.

     */

    public String toString() {

        return this.name;

    }



    /**

     * Returns <code>true</code> if this object is equal to the specified object, and

     * <code>false</code> otherwise.

     *

     * @param obj  the other object (<code>null</code> permitted).

     *

     * @return A boolean.

     */

    public boolean equals(Object obj) {



        if (this == obj) {

            return true;

        }

        if (!(obj instanceof AxisLocation)) {

            return false;

        }



        final AxisLocation location = (AxisLocation) obj;

        if (!this.name.equals(location.toString())) {

            return false;

        }



        return true;



    }

    

    /**

     * Returns the location that is opposite to the supplied location.

     * 

     * @param location  the location (<code>null</code> not permitted).

     * 

     * @return The opposite location.

     */

    public static AxisLocation getOpposite(AxisLocation location) {

        if (location == null) {

            throw new IllegalArgumentException("Null 'location' argument.");   

        }

        AxisLocation result = null;

        if (location == AxisLocation.TOP_OR_LEFT) {

            result = AxisLocation.BOTTOM_OR_RIGHT;   

        }

        else if (location == AxisLocation.TOP_OR_RIGHT) {

            result = AxisLocation.BOTTOM_OR_LEFT;   

        }

        else if (location == AxisLocation.BOTTOM_OR_LEFT) {

            result = AxisLocation.TOP_OR_RIGHT;   

        }

        else if (location == AxisLocation.BOTTOM_OR_RIGHT) {

            result = AxisLocation.TOP_OR_LEFT;   

        }

        else {

            throw new IllegalStateException("AxisLocation not recognised.");   

        }

        return result;

    }

        

    /**

     * Ensures that serialization returns the unique instances.

     * 

     * @return The object.

     * 

     * @throws ObjectStreamException if there is a problem.

     */

    private Object readResolve() throws ObjectStreamException {

        if (this.equals(AxisLocation.TOP_OR_RIGHT)) {

            return AxisLocation.TOP_OR_RIGHT;

        }

        else if (this.equals(AxisLocation.BOTTOM_OR_RIGHT)) {

            return AxisLocation.BOTTOM_OR_RIGHT;

        }    

        else if (this.equals(AxisLocation.TOP_OR_LEFT)) {

            return AxisLocation.TOP_OR_LEFT;

        }    

        else if (this.equals(AxisLocation.BOTTOM_OR_LEFT)) {

            return AxisLocation.BOTTOM_OR_LEFT;

        }

        return null;

    }

    

}

