xybardataset.java

制作图表的好工具

/* ===========================================================
 * 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.]
 *
 * -----------------
 * XYBarDataset.java
 * -----------------
 * (C) Copyright 2004, 2005, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: XYBarDataset.java,v 1.4.2.1 2005/10/25 21:36:51 mungady Exp $
 *
 * Changes
 * -------
 * 02-Mar-2004 : Version 1 (DG);
 * 05-May-2004 : Now extends AbstractIntervalXYDataset (DG);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with 
 *               getYValue() (DG);
 *
 */

package org.jfree.data.xy;

import org.jfree.data.general.DatasetChangeEvent;
import org.jfree.data.general.DatasetChangeListener;

/**
 * A dataset wrapper class that converts a standard {@link XYDataset} into an
 * {@link IntervalXYDataset} suitable for use in creating XY bar charts.
 */
public class XYBarDataset extends AbstractIntervalXYDataset
                          implements IntervalXYDataset, DatasetChangeListener {
    
    /** The underlying dataset. */
    private XYDataset underlying;
    
    /** The bar width. */
    private double barWidth;
    
    /**
     * Creates a new dataset.
     * 
     * @param underlying  the underlying dataset.
     * @param barWidth  the width of the bars.
     */
    public XYBarDataset(XYDataset underlying, double barWidth) {
        this.underlying = underlying;   
        this.underlying.addChangeListener(this);
        this.barWidth = barWidth;
    }

    /**
     * Returns the number of series in the dataset.
     *
     * @return The series count.
     */
    public int getSeriesCount() {
        return this.underlying.getSeriesCount();   
    }

    /**
     * Returns the key for a series.
     *
     * @param series  the series index (zero-based).
     *
     * @return The series key.
     */
    public Comparable getSeriesKey(int series) {
        return this.underlying.getSeriesKey(series);   
    }
    
    /**
     * Returns the number of items in a series.
     *
     * @param series  the series index (zero-based).
     *
     * @return The item count.
     */
    public int getItemCount(int series) {
        return this.underlying.getItemCount(series);   
    }

    /**
     * Returns the x-value for an item within a series.  The x-values may or 
     * may not be returned in ascending order, that is up to the class 
     * implementing the interface.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return The x-value.
     */
    public Number getX(int series, int item) {
        return this.underlying.getX(series, item);   
    }

    /**
     * Returns the y-value for an item within a series.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return The y-value (possibly <code>null</code>).
     */
    public Number getY(int series, int item) {
        return this.underlying.getY(series, item);   
    }

    /**
     * Returns the starting X value for the specified series and item.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return The value.
     */
    public Number getStartX(int series, int item) {
        Number result = null;
        Number xnum = this.underlying.getX(series, item);
        if (xnum != null) {
             result = new Double(xnum.doubleValue() - this.barWidth / 2.0);   
        }
        return result;   
    }

    /**
     * Returns the ending X value for the specified series and item.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return The value.
     */
    public Number getEndX(int series, int item) {
        Number result = null;
        Number xnum = this.underlying.getX(series, item);
        if (xnum != null) {
             result = new Double(xnum.doubleValue() + this.barWidth / 2.0);   
        }
        return result;   
    }

    /**
     * Returns the starting Y value for the specified series and item.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return The value.
     */
    public Number getStartY(int series, int item) {
        return this.underlying.getY(series, item);   
    }

    /**
     * Returns the ending Y value for the specified series and item.
     *
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     *
     * @return The value.
     */
    public Number getEndY(int series, int item) {
        return this.underlying.getY(series, item);   
    }

    /**
     * Receives notification of an dataset change event.
     *
     * @param event  information about the event.
     */
    public void datasetChanged(DatasetChangeEvent event) {
        this.notifyListeners(event);
    }

}