001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2022, by David Gilbert 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 * ComparableObjectItem.java
029 * -------------------------
030 * (C) Copyright 2006-2022, by David Gilbert.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.data;
038
039import java.io.Serializable;
040import java.util.Objects;
041
042import org.jfree.chart.internal.Args;
043
044/**
045 * Represents one (Comparable, Object) data item for use in a
046 * {@link ComparableObjectSeries}.
047 */
048public class ComparableObjectItem implements Comparable<ComparableObjectItem>, 
049        Cloneable, Serializable {
050
051    /** For serialization. */
052    private static final long serialVersionUID = 2751513470325494890L;
053
054    /** The x-value. */
055    private Comparable x;
056
057    /** The y-value. */
058    private Object obj;
059
060    /**
061     * Constructs a new data item.
062     *
063     * @param x  the x-value ({@code null} NOT permitted).
064     * @param y  the y-value ({@code null} permitted).
065     */
066    public ComparableObjectItem(Comparable x, Object y) {
067        Args.nullNotPermitted(x, "x");
068        this.x = x;
069        this.obj = y;
070    }
071
072    /**
073     * Returns the x-value.
074     *
075     * @return The x-value (never {@code null}).
076     */
077    protected Comparable getComparable() {
078        return this.x;
079    }
080
081    /**
082     * Returns the y-value.
083     *
084     * @return The y-value (possibly {@code null}).
085     */
086    protected Object getObject() {
087        return this.obj;
088    }
089
090    /**
091     * Sets the y-value for this data item.  Note that there is no
092     * corresponding method to change the x-value.
093     *
094     * @param y  the new y-value ({@code null} permitted).
095     */
096    protected void setObject(Object y) {
097        this.obj = y;
098    }
099
100    /**
101     * Returns an integer indicating the order of this object relative to
102     * another object.
103     * <P>
104     * For the order we consider only the x-value:
105     * negative == "less-than", zero == "equal", positive == "greater-than".
106     *
107     * @param other  the object being compared to.
108     *
109     * @return An integer indicating the order of this data pair object
110     *      relative to another object.
111     */
112    @Override
113    public int compareTo(ComparableObjectItem other) {
114        return this.x.compareTo(other.getComparable());
115    }
116
117    /**
118     * Returns a clone of this object.
119     *
120     * @return A clone.
121     *
122     * @throws CloneNotSupportedException not thrown by this class, but
123     *         subclasses may differ.
124     */
125    @Override
126    public Object clone() throws CloneNotSupportedException {
127        return super.clone();
128    }
129
130    /**
131     * Tests if this object is equal to another.
132     *
133     * @param obj  the object to test against for equality ({@code null}
134     *             permitted).
135     *
136     * @return A boolean.
137     */
138    @Override
139    public boolean equals(Object obj) {
140        if (obj == this) {
141            return true;
142        }
143        if (!(obj instanceof ComparableObjectItem)) {
144            return false;
145        }
146        ComparableObjectItem that = (ComparableObjectItem) obj;
147        if (!this.x.equals(that.x)) {
148            return false;
149        }
150        if (!Objects.equals(this.obj, that.obj)) {
151            return false;
152        }
153        return true;
154    }
155
156    /**
157     * Returns a hash code.
158     *
159     * @return A hash code.
160     */
161    @Override
162    public int hashCode() {
163        int result;
164        result = this.x.hashCode();
165        result = 29 * result + (this.obj != null ? this.obj.hashCode() : 0);
166        return result;
167    }
168
169}