    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    025 * Other names may be trademarks of their respective owners.]
    026 *
    027 * -----------------------------
    028 * DefaultKeyedValueDataset.java
    029 * -----------------------------
    030 * (C) Copyright 2003-2008, by Object Refinery Limited.
    031 *
    032 * Original Author:  David Gilbert (for Object Refinery Limited);
    033 * Contributor(s):   -;
    034 *
    035 * Changes
    036 * -------
    037 * 27-Mar-2003 : Version 1 (DG);
    038 * 18-Aug-2003 : Implemented Cloneable (DG);
    039 *
    040 */
    041
    042package org.jfree.data.general;
    043
    044import java.io.Serializable;
    045
    046import org.jfree.data.DefaultKeyedValue;
    047import org.jfree.data.KeyedValue;
    048import org.jfree.util.ObjectUtilities;
    049
    050/**
    051 * A default implementation of the {@link KeyedValueDataset} interface.
    052 */
    053public class DefaultKeyedValueDataset extends AbstractDataset
    054        implements KeyedValueDataset, Serializable {
    055
    056    /** For serialization. */
    057    private static final long serialVersionUID = -8149484339560406750L;
    058
    059    /** Storage for the data. */
    060    private KeyedValue data;
    061
    062    /**
    063     * Constructs a new dataset, initially empty.
    064     */
    065    public DefaultKeyedValueDataset() {
    066        this(null);
    067    }
    068
    069    /**
    070     * Creates a new dataset with the specified initial value.
    071     *
    072     * @param key  the key.
    073     * @param value  the value (<code>null</code> permitted).
    074     */
    075    public DefaultKeyedValueDataset(Comparable key, Number value) {
    076        this(new DefaultKeyedValue(key, value));
    077    }
    078
    079    /**
    080     * Creates a new dataset that uses the data from a {@link KeyedValue}
    081     * instance.
    082     *
    083     * @param data  the data (<code>null</code> permitted).
    084     */
    085    public DefaultKeyedValueDataset(KeyedValue data) {
    086        this.data = data;
    087    }
    088
    089    /**
    090     * Returns the key associated with the value, or <code>null</code> if the
    091     * dataset has no data item.
    092     *
    093     * @return The key.
    094     */
    095    public Comparable getKey() {
    096        Comparable result = null;
    097        if (this.data != null) {
    098            result = this.data.getKey();
    099        }
    100        return result;
    101    }
    102
    103    /**
    104     * Returns the value.
    105     *
    106     * @return The value (possibly <code>null</code>).
    107     */
    108    public Number getValue() {
    109        Number result = null;
    110        if (this.data != null) {
    111            result = this.data.getValue();
    112        }
    113        return result;
    114    }
    115
    116    /**
    117     * Updates the value.
    118     *
    119     * @param value  the new value (<code>null</code> permitted).
    120     */
    121    public void updateValue(Number value) {
    122        if (this.data == null) {
    123            throw new RuntimeException("updateValue: can't update null.");
    124        }
    125        setValue(this.data.getKey(), value);
    126    }
    127
    128    /**
    129     * Sets the value for the dataset and sends a {@link DatasetChangeEvent} to
    130     * all registered listeners.
    131     *
    132     * @param key  the key.
    133     * @param value  the value (<code>null</code> permitted).
    134     */
    135    public void setValue(Comparable key, Number value) {
    136        this.data = new DefaultKeyedValue(key, value);
    137        notifyListeners(new DatasetChangeEvent(this, this));
    138    }
    139
    140    /**
    141     * Tests this dataset for equality with an arbitrary object.
    142     *
    143     * @param obj  the object (<code>null</code> permitted).
    144     *
    145     * @return A boolean.
    146     */
    147    public boolean equals(Object obj) {
    148        if (obj == this) {
    149            return true;
    150        }
    151        if (!(obj instanceof KeyedValueDataset)) {
    152            return false;
    153        }
    154        KeyedValueDataset that = (KeyedValueDataset) obj;
    155        if (this.data == null) {
    156            if (that.getKey() != null || that.getValue() != null) {
    157                return false;
    158            }
    159            return true;
    160        }
    161        if (!ObjectUtilities.equal(this.data.getKey(), that.getKey())) {
    162            return false;
    163        }
    164        if (!ObjectUtilities.equal(this.data.getValue(), that.getValue())) {
    165            return false;
    166        }
    167        return true;
    168    }
    169
    170    /**
    171     * Returns a hash code.
    172     *
    173     * @return A hash code.
    174     */
    175    public int hashCode() {
    176        return (this.data != null ? this.data.hashCode() : 0);
    177    }
    178
    179    /**
    180     * Creates a clone of the dataset.
    181     *
    182     * @return A clone.
    183     *
    184     * @throws CloneNotSupportedException This class will not throw this
    185     *         exception, but subclasses (if any) might.
    186     */
    187    public Object clone() throws CloneNotSupportedException {
    188        DefaultKeyedValueDataset clone
    189                = (DefaultKeyedValueDataset) super.clone();
    190        return clone;
    191    }
    192
    193}