001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2005, 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 * TimeSeriesDataItem.java
029 * -----------------------
030 * (C) Copyright 2001-2005, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * $Id: TimeSeriesDataItem.java,v 1.5.2.1 2005/10/25 21:35:24 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 11-Oct-2001 : Version 1 (DG);
040 * 15-Nov-2001 : Updated Javadoc comments (DG);
041 * 29-Nov-2001 : Added cloning (DG);
042 * 24-Jun-2002 : Removed unnecessary import (DG);
043 * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
044 * 13-Mar-2003 : Renamed TimeSeriesDataPair --> TimeSeriesDataItem, moved to
045 * com.jrefinery.data.time package, implemented Serializable (DG)
046 */
047
048 package org.jfree.data.time;
049
050 import java.io.Serializable;
051
052 /**
053 * Represents one data item in a time series.
054 * <P>
055 * The time period can be any of the following:
056 * <ul>
057 * <li>{@link Year}</li>
058 * <li>{@link Quarter}</li>
059 * <li>{@link Month}</li>
060 * <li>{@link Week}</li>
061 * <li>{@link Day}</li>
062 * <li>{@link Hour}</li>
063 * <li>{@link Minute}</li>
064 * <li>{@link Second}</li>
065 * <li>{@link Millisecond}</li>
066 * <li>{@link FixedMillisecond}</li>
067 * </ul>
068 *
069 * The time period is an immutable property of the data item. Data items will
070 * often be sorted within a list, and allowing the time period to be changed
071 * could destroy the sort order.
072 * <P>
073 * Implements the <code>Comparable</code> interface so that standard Java
074 * sorting can be used to keep the data items in order.
075 *
076 */
077 public class TimeSeriesDataItem implements Cloneable, Comparable, Serializable {
078
079 /** For serialization. */
080 private static final long serialVersionUID = -2235346966016401302L;
081
082 /** The time period. */
083 private RegularTimePeriod period;
084
085 /** The value associated with the time period. */
086 private Number value;
087
088 /**
089 * Constructs a new data item that associates a value with a time period.
090 *
091 * @param period the time period (<code>null</code> not permitted).
092 * @param value the value (<code>null</code> permitted).
093 */
094 public TimeSeriesDataItem(RegularTimePeriod period, Number value) {
095 if (period == null) {
096 throw new IllegalArgumentException("Null 'period' argument.");
097 }
098 this.period = period;
099 this.value = value;
100 }
101
102 /**
103 * Constructs a new data item that associates a value with a time period.
104 *
105 * @param period the time period (<code>null</code> not permitted).
106 * @param value the value associated with the time period.
107 */
108 public TimeSeriesDataItem(RegularTimePeriod period, double value) {
109 this(period, new Double(value));
110 }
111
112 /**
113 * Returns the time period.
114 *
115 * @return The time period (never <code>null</code>).
116 */
117 public RegularTimePeriod getPeriod() {
118 return this.period;
119 }
120
121 /**
122 * Returns the value.
123 *
124 * @return The value (<code>null</code> possible).
125 */
126 public Number getValue() {
127 return this.value;
128 }
129
130 /**
131 * Sets the value for this data item.
132 *
133 * @param value the value (<code>null</code> permitted).
134 */
135 public void setValue(Number value) {
136 this.value = value;
137 }
138
139 /**
140 * Tests this object for equality with an arbitrary object.
141 *
142 * @param o the other object.
143 *
144 * @return A boolean.
145 */
146 public boolean equals(Object o) {
147 if (this == o) {
148 return true;
149 }
150 if (!(o instanceof TimeSeriesDataItem)) {
151 return false;
152 }
153 TimeSeriesDataItem timeSeriesDataItem = (TimeSeriesDataItem) o;
154 if (this.period != null) {
155 if (!this.period.equals(timeSeriesDataItem.period)) {
156 return false;
157 }
158 }
159 else if (timeSeriesDataItem.period != null) {
160 return false;
161 }
162
163 if (this.value != null) {
164 if (!this.value.equals(timeSeriesDataItem.value)) {
165 return false;
166 }
167 }
168 else if (timeSeriesDataItem.value != null) {
169 return false;
170 }
171
172 return true;
173 }
174
175 /**
176 * Returns a hash code.
177 *
178 * @return A hash code.
179 */
180 public int hashCode() {
181 int result;
182 result = (this.period != null ? this.period.hashCode() : 0);
183 result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
184 return result;
185 }
186
187 /**
188 * Returns an integer indicating the order of this data pair object
189 * relative to another object.
190 * <P>
191 * For the order we consider only the timing:
192 * negative == before, zero == same, positive == after.
193 *
194 * @param o1 The object being compared to.
195 *
196 * @return An integer indicating the order of the data item object
197 * relative to another object.
198 */
199 public int compareTo(Object o1) {
200
201 int result;
202
203 // CASE 1 : Comparing to another TimeSeriesDataItem object
204 // -------------------------------------------------------
205 if (o1 instanceof TimeSeriesDataItem) {
206 TimeSeriesDataItem datapair = (TimeSeriesDataItem) o1;
207 result = getPeriod().compareTo(datapair.getPeriod());
208 }
209
210 // CASE 2 : Comparing to a general object
211 // ---------------------------------------------
212 else {
213 // consider time periods to be ordered after general objects
214 result = 1;
215 }
216
217 return result;
218
219 }
220
221 /**
222 * Clones the data item. Note: there is no need to clone the period or
223 * value since they are immutable classes.
224 *
225 * @return A clone of the data item.
226 */
227 public Object clone() {
228 Object clone = null;
229 try {
230 clone = super.clone();
231 }
232 catch (CloneNotSupportedException e) { // won't get here...
233 e.printStackTrace();
234 }
235 return clone;
236 }
237
238 }