/* ===========================================================
 * 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.]
 *
 * -----------------------
 * IntervalXYDelegate.java
 * -----------------------
 * (C) Copyright 2004, 2005, by Andreas Schroeder and Contributors.
 *
 * Original Author:  Andreas Schroeder;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: IntervalXYDelegate.java,v 1.10.2.2 2005/10/25 21:36:51 mungady Exp $
 *
 * Changes (from 31-Mar-2004)
 * --------------------------
 * 31-Mar-2004 : Version 1 (AS);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with 
 *               getYValue() (DG);
 * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.xy (DG);
 * 04-Nov-2004 : Added argument check for setIntervalWidth() method (DG);
 * 17-Nov-2004 : New methods to reflect changes in DomainInfo (DG);
 * 11-Jan-2005 : Removed deprecated methods in preparation for the 1.0.0 
 *               release (DG);
 * 21-Feb-2005 : Made public and added equals() method (DG);
 * 06-Oct-2005 : Implemented DatasetChangeListener to recalculate 
 *               autoIntervalWidth (DG);
 *   
 */

package org.jfree.data.xy;

import java.io.Serializable;

import org.jfree.data.DomainInfo;
import org.jfree.data.Range;
import org.jfree.data.RangeInfo;
import org.jfree.data.general.DatasetChangeEvent;
import org.jfree.data.general.DatasetChangeListener;
import org.jfree.data.general.DatasetUtilities;
import org.jfree.util.PublicCloneable;

/**
 * A delegate that handles the specification or automatic calculation of the
 * interval surrounding the x-values in a dataset.  This is used to extend
 * a regular {@link XYDataset} to support the {@link IntervalXYDataset} 
 * interface.
 * <p> 
 * The decorator pattern was not used because of the several possibly 
 * implemented interfaces of the decorated instance (e.g. 
 * {@link TableXYDataset}, {@link RangeInfo}, {@link DomainInfo} etc.).
 * <p>
 * The width can be set manually or calculated automatically. The switch
 * autoWidth allows to determine which behavior is used. The auto width 
 * calculation tries to find the smallest gap between two x-values in the
 * dataset.  If there is only one item in the series, the auto width 
 * calculation fails and falls back on the manually set interval width (which 
 * is itself defaulted to 1.0). 
 * 
 * @author andreas.schroeder
 */
public class IntervalXYDelegate implements DatasetChangeListener,
                                           DomainInfo, Serializable, 
                                           Cloneable, PublicCloneable {
    
    /** For serialization. */
    private static final long serialVersionUID = -685166711639592857L;
    
    /**
     * The dataset to enhance. 
     */
    private XYDataset dataset;

    /**
     * A flag to indicate whether the width should be calculated automatically.
     */
    private boolean autoWidth;
    
    /**
     * A value between 0.0 and 1.0 that indicates the position of the x-value
     * within the interval.
     */
    private double intervalPositionFactor; 
    
    /**
     * The fixed interval width (defaults to 1.0).
     */
    private double fixedIntervalWidth;
    
    /**
     * The automatically calculated interval width.
     */
    private double autoIntervalWidth;
    
    /**
     * Creates a new delegate that.
     * 
     * @param dataset  the underlying dataset (<code>null</code> not permitted).
     */
    public IntervalXYDelegate(XYDataset dataset) {
        this(dataset, true);
    }
    
    /**
     * Creates a new delegate for the specified dataset.
     * 
     * @param dataset  the underlying dataset (<code>null</code> not permitted).
     * @param autoWidth  a flag that controls whether the interval width is 
     *                   calculated automatically.
     */
    public IntervalXYDelegate(XYDataset dataset, boolean autoWidth) {
        if (dataset == null) {
            throw new IllegalArgumentException("Null 'dataset' argument.");
        }
        this.dataset = dataset;
        this.autoWidth = autoWidth;
        this.intervalPositionFactor = 0.5;
        this.autoIntervalWidth = Double.POSITIVE_INFINITY; 
        this.fixedIntervalWidth = 1.0;
    }
    
    /**
     * Returns <code>true</code> if the interval width is automatically 
     * calculated, and <code>false</code> otherwise.
     * 
     * @return A boolean.
     */
    public boolean isAutoWidth() {
        return this.autoWidth;
    }
    
    /**
     * Sets the flag that indicates whether the interval width is automatically
     * calculated.  If the flag is set to <code>true</code>, the interval is
     * recalculated.
     * <p>
     * Note: recalculating the interval amounts to changing the data values
     * represented by the dataset.  The calling dataset must fire an
     * appropriate {@link DatasetChangeEvent}.
     * 
     * @param b  a boolean.
     */
    public void setAutoWidth(boolean b) {
        this.autoWidth = b;
        if (b) {
            this.autoIntervalWidth = recalculateInterval();
        }
    }
    
    /**
     * Returns the interval position factor.
     * 
     * @return The interval position factor.
     */
    public double getIntervalPositionFactor() {
        return this.intervalPositionFactor;
    }

    /**
     * Sets the interval position factor.  This controls how the interval is
     * aligned to the x-value.  For a value of 0.5, the interval is aligned
     * with the x-value in the center.  For a value of 0.0, the interval is
     * aligned with the x-value at the lower end of the interval, and for a 
     * value of 1.0, the interval is aligned with the x-value at the upper
     * end of the interval.
     * 
     * Note that changing the interval position factor amounts to changing the 
     * data values represented by the dataset.  Therefore, the dataset that is 
     * using this delegate is responsible for generating the 
     * appropriate {@link DatasetChangeEvent}.     
     * 
     * @param d  the new interval position factor (in the range 
     *           <code>0.0</code> to <code>1.0</code> inclusive).
     */
    public void setIntervalPositionFactor(double d) {
        if (d < 0.0 || 1.0 < d) {
            throw new IllegalArgumentException(
                    "Argument 'd' outside valid range.");
        }
        this.intervalPositionFactor = d;
    }

    /**
     * Returns the fixed interval width.
     * 
     * @return The fixed interval width.
     */
    public double getFixedIntervalWidth() {
        return this.fixedIntervalWidth;
    }
    
    /**
     * Sets the fixed interval width and, as a side effect, sets the
     * <code>autoWidth</code> flag to <code>false</code>.  
     * 
     * Note that changing the interval width amounts to changing the data 
     * values represented by the dataset.  Therefore, the dataset
     * that is using this delegate is responsible for generating the 
     * appropriate {@link DatasetChangeEvent}.
     * 
     * @param w  the width (negative values not permitted).
     */
    public void setFixedIntervalWidth(double w) {
        if (w < 0.0) {
            throw new IllegalArgumentException("Negative 'w' argument.");
        }
        this.fixedIntervalWidth = w;
        this.autoWidth = false;
    }