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jfreechart example source code file (DefaultKeyedValue.java)

This example jfreechart source code file (DefaultKeyedValue.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, comparable, comparable, defaultkeyedvalue, defaultkeyedvalue, illegalargumentexception, io, null, number, number, object, publiccloneable, publiccloneable, serializable, string

The jfreechart DefaultKeyedValue.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, 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.]
 *
 * ----------------------
 * DefaultKeyedValue.java
 * ----------------------
 * (C) Copyright 2002-2008, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes:
 * --------
 * 31-Oct-2002 : Version 1 (DG);
 * 13-Mar-2003 : Added equals() method, and implemented Serializable (DG);
 * 18-Aug-2003 : Implemented Cloneable (DG);
 * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.base (DG);
 * 15-Sep-2004 : Added PublicCloneable interface (DG);
 * ------------- JFREECHART 1.0.x ---------------------------------------------
 * 11-Jun-2007 : Added toString() method to help with debugging (DG);
 * 15-Feb-2008 : Prevent null key (DG);
 * 07-Apr-2008 : Removed to-do item (DG);
 *
 */

package org.jfree.data;

import java.io.Serializable;

import org.jfree.util.PublicCloneable;

/**
 * A (key, value) pair.  This class provides a default implementation
 * of the {@link KeyedValue} interface.
 */
public class DefaultKeyedValue implements KeyedValue, Cloneable,
        PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -7388924517460437712L;

    /** The key. */
    private Comparable key;

    /** The value. */
    private Number value;

    /**
     * Creates a new (key, value) item.
     *
     * @param key  the key (should be immutable, <code>null not
     *         permitted).
     * @param value  the value (<code>null permitted).
     */
    public DefaultKeyedValue(Comparable key, Number value) {
        if (key == null) {
            throw new IllegalArgumentException("Null 'key' argument.");
        }
        this.key = key;
        this.value = value;
    }

    /**
     * Returns the key.
     *
     * @return The key (never <code>null).
     */
    public Comparable getKey() {
        return this.key;
    }

    /**
     * Returns the value.
     *
     * @return The value (possibly <code>null).
     */
    public Number getValue() {
        return this.value;
    }

    /**
     * Sets the value.
     *
     * @param value  the value (<code>null permitted).
     */
    public synchronized void setValue(Number value) {
        this.value = value;
    }

    /**
     * Tests this key-value pair for equality with an arbitrary object.
     *
     * @param obj  the object (<code>null permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof DefaultKeyedValue)) {
            return false;
        }
        DefaultKeyedValue that = (DefaultKeyedValue) obj;

        if (!this.key.equals(that.key)) {
            return false;
        }
        if (this.value != null
                ? !this.value.equals(that.value) : that.value != null) {
            return false;
        }
        return true;
    }

    /**
     * Returns a hash code.
     *
     * @return A hash code.
     */
    public int hashCode() {
        int result;
        result = (this.key != null ? this.key.hashCode() : 0);
        result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
        return result;
    }

    /**
     * Returns a clone.  It is assumed that both the key and value are
     * immutable objects, so only the references are cloned, not the objects
     * themselves.
     *
     * @return A clone.
     *
     * @throws CloneNotSupportedException Not thrown by this class, but
     *         subclasses (if any) might.
     */
    public Object clone() throws CloneNotSupportedException {
        DefaultKeyedValue clone = (DefaultKeyedValue) super.clone();
        return clone;
    }

    /**
     * Returns a string representing this instance, primarily useful for
     * debugging.
     *
     * @return A string.
     */
    public String toString() {
        return "(" + this.key.toString() + ", " + this.value.toString() + ")";
    }

}

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