001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2007, 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 2004-2007, by Object Refinery Limited.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * Changes:
036     * --------
037     * 22-Oct-2004 : Version 1 (DG);
038     * 04-Feb-2005 : Now cloneable and serializable (DG);
039     * 20-Apr-2005 : Added new draw() method (DG);
040     * 
041     */
042    
043    package org.jfree.chart.block;
044    
045    import java.awt.Graphics2D;
046    import java.awt.geom.Rectangle2D;
047    import java.io.Serializable;
048    
049    import org.jfree.util.PublicCloneable;
050    
051    /**
052     * An empty block with a fixed size.
053     */
054    public class EmptyBlock extends AbstractBlock 
055                            implements Block, Cloneable, PublicCloneable,
056                                       Serializable {
057        
058        /** For serialization. */
059        private static final long serialVersionUID = -4083197869412648579L;
060        
061        /**
062         * Creates a new block with the specified width and height.
063         * 
064         * @param width  the width.
065         * @param height  the height.
066         */
067        public EmptyBlock(double width, double height) {
068            setWidth(width);
069            setHeight(height);
070        }
071    
072        /**
073         * Draws the block.  Since the block is empty, this method does nothing.
074         * 
075         * @param g2  the graphics device.
076         * @param area  the area.
077         */
078        public void draw(Graphics2D g2, Rectangle2D area) {
079            // do nothing, we're empty
080        }
081        
082        /**
083         * Draws the block within the specified area.  Since the block is empty, 
084         * this method does nothing.
085         * 
086         * @param g2  the graphics device.
087         * @param area  the area.
088         * @param params  ignored (<code>null</code> permitted).
089         * 
090         * @return Always <code>null</code>.
091         */
092        public Object draw(Graphics2D g2, Rectangle2D area, Object params) {
093            return null;
094        }
095    
096        /**
097         * Returns a clone of the block.
098         * 
099         * @return A clone.
100         * 
101         * @throws CloneNotSupportedException if there is a problem cloning.
102         */
103        public Object clone() throws CloneNotSupportedException {
104            return super.clone();   
105        }
106    
107    }