    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2008, 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     * 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
    042    package org.jfree.data.general;
    043
    044    import java.io.Serializable;
    045
    046    import org.jfree.data.DefaultKeyedValue;
    047    import org.jfree.data.KeyedValue;
    048    import org.jfree.util.ObjectUtilities;
    049
    050    /**
    051     * A default implementation of the {@link KeyedValueDataset} interface.
    052     */
    053    public 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    }