001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006     *
007     * Project Info:  http://www.jfree.org/jfreechart/index.html
008     *
009     * This library is free software; you can redistribute it and/or modify it 
010     * under the terms of the GNU Lesser General Public License as published by 
011     * the Free Software Foundation; either version 2.1 of the License, or 
012     * (at your option) any later version.
013     *
014     * This library is distributed in the hope that it will be useful, but 
015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017     * License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this library; if not, write to the Free Software
021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022     * USA.  
023     *
024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025     * in the United States and other countries.]
026     *
027     * ---------------
028     * EmptyBlock.java
029     * ---------------
030     * (C) Copyright 2004, 2005, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * $Id: EmptyBlock.java,v 1.4.2.1 2005/10/25 20:39:38 mungady Exp $
036     *
037     * Changes:
038     * --------
039     * 22-Oct-2004 : Version 1 (DG);
040     * 04-Feb-2005 : Now cloneable and serializable (DG);
041     * 20-Apr-2005 : Added new draw() method (DG);
042     * 
043     */
044    
045    package org.jfree.chart.block;
046    
047    import java.awt.Graphics2D;
048    import java.awt.geom.Rectangle2D;
049    import java.io.Serializable;
050    
051    import org.jfree.util.PublicCloneable;
052    
053    /**
054     * An empty block with a fixed size.
055     */
056    public class EmptyBlock extends AbstractBlock 
057                            implements Block, Cloneable, PublicCloneable,
058                                       Serializable {
059        
060        /** For serialization. */
061        private static final long serialVersionUID = -4083197869412648579L;
062        
063        /**
064         * Creates a new block with the specified width and height.
065         * 
066         * @param width  the width.
067         * @param height  the height.
068         */
069        public EmptyBlock(double width, double height) {
070            setWidth(width);
071            setHeight(height);
072        }
073    
074        /**
075         * Draws the block.  Since the block is empty, this method does nothing.
076         * 
077         * @param g2  the graphics device.
078         * @param area  the area.
079         */
080        public void draw(Graphics2D g2, Rectangle2D area) {
081            // do nothing, we're empty
082        }
083        
084        /**
085         * Draws the block within the specified area.  Since the block is empty, 
086         * this method does nothing.
087         * 
088         * @param g2  the graphics device.
089         * @param area  the area.
090         * @param params  ignored (<code>null</code> permitted).
091         * 
092         * @return Always <code>null</code>.
093         */
094        public Object draw(Graphics2D g2, Rectangle2D area, Object params) {
095            return null;
096        }
097    
098        /**
099         * Returns a clone of the block.
100         * 
101         * @return A clone.
102         * 
103         * @throws CloneNotSupportedException if there is a problem cloning.
104         */
105        public Object clone() throws CloneNotSupportedException {
106            return super.clone();   
107        }
108    
109    }