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 * ComparableObjectItem.java
029 * -------------------------
030 * (C) Copyright 2006-2008, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes
036 * -------
037 * 19-Oct-2006 : New class, based on XYDataItem (DG);
038 *
039 */
040
041 package org.jfree.data;
042
043 import java.io.Serializable;
044
045 import org.jfree.util.ObjectUtilities;
046
047 /**
048 * Represents one (Comparable, Object) data item for use in a
049 * {@link ComparableObjectSeries}.
050 *
051 * @since 1.0.3
052 */
053 public class ComparableObjectItem implements Cloneable, Comparable,
054 Serializable {
055
056 /** For serialization. */
057 private static final long serialVersionUID = 2751513470325494890L;
058
059 /** The x-value. */
060 private Comparable x;
061
062 /** The y-value. */
063 private Object obj;
064
065 /**
066 * Constructs a new data item.
067 *
068 * @param x the x-value (<code>null</code> NOT permitted).
069 * @param y the y-value (<code>null</code> permitted).
070 */
071 public ComparableObjectItem(Comparable x, Object y) {
072 if (x == null) {
073 throw new IllegalArgumentException("Null 'x' argument.");
074 }
075 this.x = x;
076 this.obj = y;
077 }
078
079 /**
080 * Returns the x-value.
081 *
082 * @return The x-value (never <code>null</code>).
083 */
084 protected Comparable getComparable() {
085 return this.x;
086 }
087
088 /**
089 * Returns the y-value.
090 *
091 * @return The y-value (possibly <code>null</code>).
092 */
093 protected Object getObject() {
094 return this.obj;
095 }
096
097 /**
098 * Sets the y-value for this data item. Note that there is no
099 * corresponding method to change the x-value.
100 *
101 * @param y the new y-value (<code>null</code> permitted).
102 */
103 protected void setObject(Object y) {
104 this.obj = y;
105 }
106
107 /**
108 * Returns an integer indicating the order of this object relative to
109 * another object.
110 * <P>
111 * For the order we consider only the x-value:
112 * negative == "less-than", zero == "equal", positive == "greater-than".
113 *
114 * @param o1 the object being compared to.
115 *
116 * @return An integer indicating the order of this data pair object
117 * relative to another object.
118 */
119 public int compareTo(Object o1) {
120
121 int result;
122
123 // CASE 1 : Comparing to another ComparableObjectItem object
124 // ---------------------------------------------------------
125 if (o1 instanceof ComparableObjectItem) {
126 ComparableObjectItem that = (ComparableObjectItem) o1;
127 return this.x.compareTo(that.x);
128 }
129
130 // CASE 2 : Comparing to a general object
131 // ---------------------------------------------
132 else {
133 // consider these to be ordered after general objects
134 result = 1;
135 }
136
137 return result;
138
139 }
140
141 /**
142 * Returns a clone of this object.
143 *
144 * @return A clone.
145 *
146 * @throws CloneNotSupportedException not thrown by this class, but
147 * subclasses may differ.
148 */
149 public Object clone() throws CloneNotSupportedException {
150 return super.clone();
151 }
152
153 /**
154 * Tests if this object is equal to another.
155 *
156 * @param obj the object to test against for equality (<code>null</code>
157 * permitted).
158 *
159 * @return A boolean.
160 */
161 public boolean equals(Object obj) {
162 if (obj == this) {
163 return true;
164 }
165 if (!(obj instanceof ComparableObjectItem)) {
166 return false;
167 }
168 ComparableObjectItem that = (ComparableObjectItem) obj;
169 if (!this.x.equals(that.x)) {
170 return false;
171 }
172 if (!ObjectUtilities.equal(this.obj, that.obj)) {
173 return false;
174 }
175 return true;
176 }
177
178 /**
179 * Returns a hash code.
180 *
181 * @return A hash code.
182 */
183 public int hashCode() {
184 int result;
185 result = this.x.hashCode();
186 result = 29 * result + (this.obj != null ? this.obj.hashCode() : 0);
187 return result;
188 }
189
190 }