    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     * DefaultKeyedValue.java
    029     * ----------------------
    030     * (C) Copyright 2002-2008, by Object Refinery Limited.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   -;
    034     *
    035     * Changes:
    036     * --------
    037     * 31-Oct-2002 : Version 1 (DG);
    038     * 13-Mar-2003 : Added equals() method, and implemented Serializable (DG);
    039     * 18-Aug-2003 : Implemented Cloneable (DG);
    040     * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.base (DG);
    041     * 15-Sep-2004 : Added PublicCloneable interface (DG);
    042     * ------------- JFREECHART 1.0.x ---------------------------------------------
    043     * 11-Jun-2007 : Added toString() method to help with debugging (DG);
    044     * 15-Feb-2008 : Prevent null key (DG);
    045     * 07-Apr-2008 : Removed to-do item (DG);
    046     *
    047     */
    048
    049    package org.jfree.data;
    050
    051    import java.io.Serializable;
    052
    053    import org.jfree.util.PublicCloneable;
    054
    055    /**
    056     * A (key, value) pair.  This class provides a default implementation
    057     * of the {@link KeyedValue} interface.
    058     */
    059    public class DefaultKeyedValue implements KeyedValue,
    060                                              Cloneable, PublicCloneable,
    061                                              Serializable {
    062
    063        /** For serialization. */
    064        private static final long serialVersionUID = -7388924517460437712L;
    065
    066        /** The key. */
    067        private Comparable key;
    068
    069        /** The value. */
    070        private Number value;
    071
    072        /**
    073         * Creates a new (key, value) item.
    074         *
    075         * @param key  the key (should be immutable, <code>null</code> not
    076         *         permitted).
    077         * @param value  the value (<code>null</code> permitted).
    078         */
    079        public DefaultKeyedValue(Comparable key, Number value) {
    080            if (key == null) {
    081                throw new IllegalArgumentException("Null 'key' argument.");
    082            }
    083            this.key = key;
    084            this.value = value;
    085        }
    086
    087        /**
    088         * Returns the key.
    089         *
    090         * @return The key (never <code>null</code>).
    091         */
    092        public Comparable getKey() {
    093            return this.key;
    094        }
    095
    096        /**
    097         * Returns the value.
    098         *
    099         * @return The value (possibly <code>null</code>).
    100         */
    101        public Number getValue() {
    102            return this.value;
    103        }
    104
    105        /**
    106         * Sets the value.
    107         *
    108         * @param value  the value (<code>null</code> permitted).
    109         */
    110        public synchronized void setValue(Number value) {
    111            this.value = value;
    112        }
    113
    114        /**
    115         * Tests this key-value pair for equality with an arbitrary object.
    116         *
    117         * @param obj  the object (<code>null</code> permitted).
    118         *
    119         * @return A boolean.
    120         */
    121        public boolean equals(Object obj) {
    122            if (obj == this) {
    123                return true;
    124            }
    125            if (!(obj instanceof DefaultKeyedValue)) {
    126                return false;
    127            }
    128            DefaultKeyedValue that = (DefaultKeyedValue) obj;
    129
    130            if (!this.key.equals(that.key)) {
    131                return false;
    132            }
    133            if (this.value != null
    134                    ? !this.value.equals(that.value) : that.value != null) {
    135                return false;
    136            }
    137            return true;
    138        }
    139
    140        /**
    141         * Returns a hash code.
    142         *
    143         * @return A hash code.
    144         */
    145        public int hashCode() {
    146            int result;
    147            result = (this.key != null ? this.key.hashCode() : 0);
    148            result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
    149            return result;
    150        }
    151
    152        /**
    153         * Returns a clone.  It is assumed that both the key and value are
    154         * immutable objects, so only the references are cloned, not the objects
    155         * themselves.
    156         *
    157         * @return A clone.
    158         *
    159         * @throws CloneNotSupportedException Not thrown by this class, but
    160         *         subclasses (if any) might.
    161         */
    162        public Object clone() throws CloneNotSupportedException {
    163            DefaultKeyedValue clone = (DefaultKeyedValue) super.clone();
    164            return clone;
    165        }
    166
    167        /**
    168         * Returns a string representing this instance, primarily useful for
    169         * debugging.
    170         *
    171         * @return A string.
    172         */
    173        public String toString() {
    174            return "(" + this.key.toString() + ", " + this.value.toString() + ")";
    175        }
    176
    177    }