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jfreechart example source code file (IntervalXYDelegate.java)

This example jfreechart source code file (IntervalXYDelegate.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - jfreechart tags/keywords

clonenotsupportedexception, domaininfo, illegalargumentexception, illegalargumentexception, intervalxydelegate, intervalxydelegate, io, number, number, object, publiccloneable, range, range, serializable, xydataset

The jfreechart IntervalXYDelegate.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2009, 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 2004-2009, by Andreas Schroeder and Contributors.
 *
 * Original Author:  Andreas Schroeder;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * Changes
 * -------
 * 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);
 * 02-Feb-2007 : Removed author tags all over JFreeChart sources (DG);
 * 06-Mar-2009 : Implemented hashCode() (DG);
 *
 */

package org.jfree.data.xy;

import java.io.Serializable;

import org.jfree.chart.HashUtilities;
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).
 */
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 not permitted).
     */
    public IntervalXYDelegate(XYDataset dataset) {
        this(dataset, true);
    }

    /**
     * Creates a new delegate for the specified dataset.
     *
     * @param dataset  the underlying dataset (<code>null 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 if the interval width is automatically
     * calculated, and <code>false 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, 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.
     * <br>
* 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 to 1.0 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 flag to false. * <br>
* 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; } /** * Returns the interval width. This method will return either the * auto calculated interval width or the manually specified interval * width, depending on the {@link #isAutoWidth()} result. * * @return The interval width to use. */ public double getIntervalWidth() { if (isAutoWidth() && !Double.isInfinite(this.autoIntervalWidth)) { // everything is fine: autoWidth is on, and an autoIntervalWidth // was set. return this.autoIntervalWidth; } else { // either autoWidth is off or autoIntervalWidth was not set. return this.fixedIntervalWidth; } } /** * Returns the start value of the x-interval for an item within a series. * * @param series the series index. * @param item the item index. * * @return The start value of the x-interval (possibly <code>null). * * @see #getStartXValue(int, int) */ public Number getStartX(int series, int item) { Number startX = null; Number x = this.dataset.getX(series, item); if (x != null) { startX = new Double(x.doubleValue() - (getIntervalPositionFactor() * getIntervalWidth())); } return startX; } /** * Returns the start value of the x-interval for an item within a series. * * @param series the series index. * @param item the item index. * * @return The start value of the x-interval. * * @see #getStartX(int, int) */ public double getStartXValue(int series, int item) { return this.dataset.getXValue(series, item) - getIntervalPositionFactor() * getIntervalWidth(); } /** * Returns the end value of the x-interval for an item within a series. * * @param series the series index. * @param item the item index. * * @return The end value of the x-interval (possibly <code>null). * * @see #getEndXValue(int, int) */ public Number getEndX(int series, int item) { Number endX = null; Number x = this.dataset.getX(series, item); if (x != null) { endX = new Double(x.doubleValue() + ((1.0 - getIntervalPositionFactor()) * getIntervalWidth())); } return endX; } /** * Returns the end value of the x-interval for an item within a series. * * @param series the series index. * @param item the item index. * * @return The end value of the x-interval. * * @see #getEndX(int, int) */ public double getEndXValue(int series, int item) { return this.dataset.getXValue(series, item) + (1.0 - getIntervalPositionFactor()) * getIntervalWidth(); } /** * Returns the minimum x-value in the dataset. * * @param includeInterval a flag that determines whether or not the * x-interval is taken into account. * * @return The minimum value. */ public double getDomainLowerBound(boolean includeInterval) { double result = Double.NaN; Range r = getDomainBounds(includeInterval); if (r != null) { result = r.getLowerBound(); } return result; } /** * Returns the maximum x-value in the dataset. * * @param includeInterval a flag that determines whether or not the * x-interval is taken into account. * * @return The maximum value. */ public double getDomainUpperBound(boolean includeInterval) { double result = Double.NaN; Range r = getDomainBounds(includeInterval); if (r != null) { result = r.getUpperBound(); } return result; } /** * Returns the range of the values in the dataset's domain, including * or excluding the interval around each x-value as specified. * * @param includeInterval a flag that determines whether or not the * x-interval should be taken into account. * * @return The range. */ public Range getDomainBounds(boolean includeInterval) { // first get the range without the interval, then expand it for the // interval width Range range = DatasetUtilities.findDomainBounds(this.dataset, false); if (includeInterval && range != null) { double lowerAdj = getIntervalWidth() * getIntervalPositionFactor(); double upperAdj = getIntervalWidth() - lowerAdj; range = new Range(range.getLowerBound() - lowerAdj, range.getUpperBound() + upperAdj); } return range; } /** * Handles events from the dataset by recalculating the interval if * necessary. * * @param e the event. */ public void datasetChanged(DatasetChangeEvent e) { // TODO: by coding the event with some information about what changed // in the dataset, we could make the recalculation of the interval // more efficient in some cases (for instance, if the change is // just an update to a y-value, then the x-interval doesn't need // updating)... if (this.autoWidth) { this.autoIntervalWidth = recalculateInterval(); } } /** * Recalculate the minimum width "from scratch". * * @return The minimum width. */ private double recalculateInterval() { double result = Double.POSITIVE_INFINITY; int seriesCount = this.dataset.getSeriesCount(); for (int series = 0; series < seriesCount; series++) { result = Math.min(result, calculateIntervalForSeries(series)); } return result; } /** * Calculates the interval width for a given series. * * @param series the series index. * * @return The interval width. */ private double calculateIntervalForSeries(int series) { double result = Double.POSITIVE_INFINITY; int itemCount = this.dataset.getItemCount(series); if (itemCount > 1) { double prev = this.dataset.getXValue(series, 0); for (int item = 1; item < itemCount; item++) { double x = this.dataset.getXValue(series, item); result = Math.min(result, x - prev); prev = x; } } return result; } /** * Tests the delegate for equality with an arbitrary object. The * equality test considers two delegates to be equal if they would * calculate the same intervals for any given dataset (for this reason, the * dataset itself is NOT included in the equality test, because it is just * a reference back to the current 'owner' of the delegate). * * @param obj the object (<code>null permitted). * * @return A boolean. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof IntervalXYDelegate)) { return false; } IntervalXYDelegate that = (IntervalXYDelegate) obj; if (this.autoWidth != that.autoWidth) { return false; } if (this.intervalPositionFactor != that.intervalPositionFactor) { return false; } if (this.fixedIntervalWidth != that.fixedIntervalWidth) { return false; } return true; } /** * @return A clone of this delegate. * * @throws CloneNotSupportedException if the object cannot be cloned. */ public Object clone() throws CloneNotSupportedException { return super.clone(); } /** * Returns a hash code for this instance. * * @return A hash code. */ public int hashCode() { int hash = 5; hash = HashUtilities.hashCode(hash, this.autoWidth); hash = HashUtilities.hashCode(hash, this.intervalPositionFactor); hash = HashUtilities.hashCode(hash, this.fixedIntervalWidth); return hash; } }

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