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 * TimeSeriesDataItem.java
029 * -----------------------
030 * (C) Copyright 2001-2008, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes
036 * -------
037 * 11-Oct-2001 : Version 1 (DG);
038 * 15-Nov-2001 : Updated Javadoc comments (DG);
039 * 29-Nov-2001 : Added cloning (DG);
040 * 24-Jun-2002 : Removed unnecessary import (DG);
041 * 07-Oct-2002 : Fixed errors reported by Checkstyle (DG);
042 * 13-Mar-2003 : Renamed TimeSeriesDataPair --> TimeSeriesDataItem, moved to
043 * com.jrefinery.data.time package, implemented Serializable (DG)
044 */
045
046 package org.jfree.data.time;
047
048 import java.io.Serializable;
049
050 /**
051 * Represents one data item in a time series.
052 * <P>
053 * The time period can be any of the following:
054 * <ul>
055 * <li>{@link Year}</li>
056 * <li>{@link Quarter}</li>
057 * <li>{@link Month}</li>
058 * <li>{@link Week}</li>
059 * <li>{@link Day}</li>
060 * <li>{@link Hour}</li>
061 * <li>{@link Minute}</li>
062 * <li>{@link Second}</li>
063 * <li>{@link Millisecond}</li>
064 * <li>{@link FixedMillisecond}</li>
065 * </ul>
066 *
067 * The time period is an immutable property of the data item. Data items will
068 * often be sorted within a list, and allowing the time period to be changed
069 * could destroy the sort order.
070 * <P>
071 * Implements the <code>Comparable</code> interface so that standard Java
072 * sorting can be used to keep the data items in order.
073 *
074 */
075 public class TimeSeriesDataItem implements Cloneable, Comparable, Serializable {
076
077 /** For serialization. */
078 private static final long serialVersionUID = -2235346966016401302L;
079
080 /** The time period. */
081 private RegularTimePeriod period;
082
083 /** The value associated with the time period. */
084 private Number value;
085
086 /**
087 * Constructs a new data item that associates a value with a time period.
088 *
089 * @param period the time period (<code>null</code> not permitted).
090 * @param value the value (<code>null</code> permitted).
091 */
092 public TimeSeriesDataItem(RegularTimePeriod period, Number value) {
093 if (period == null) {
094 throw new IllegalArgumentException("Null 'period' argument.");
095 }
096 this.period = period;
097 this.value = value;
098 }
099
100 /**
101 * Constructs a new data item that associates a value with a time period.
102 *
103 * @param period the time period (<code>null</code> not permitted).
104 * @param value the value associated with the time period.
105 */
106 public TimeSeriesDataItem(RegularTimePeriod period, double value) {
107 this(period, new Double(value));
108 }
109
110 /**
111 * Returns the time period.
112 *
113 * @return The time period (never <code>null</code>).
114 */
115 public RegularTimePeriod getPeriod() {
116 return this.period;
117 }
118
119 /**
120 * Returns the value.
121 *
122 * @return The value (<code>null</code> possible).
123 */
124 public Number getValue() {
125 return this.value;
126 }
127
128 /**
129 * Sets the value for this data item.
130 *
131 * @param value the value (<code>null</code> permitted).
132 */
133 public void setValue(Number value) {
134 this.value = value;
135 }
136
137 /**
138 * Tests this object for equality with an arbitrary object.
139 *
140 * @param o the other object.
141 *
142 * @return A boolean.
143 */
144 public boolean equals(Object o) {
145 if (this == o) {
146 return true;
147 }
148 if (!(o instanceof TimeSeriesDataItem)) {
149 return false;
150 }
151 TimeSeriesDataItem timeSeriesDataItem = (TimeSeriesDataItem) o;
152 if (this.period != null) {
153 if (!this.period.equals(timeSeriesDataItem.period)) {
154 return false;
155 }
156 }
157 else if (timeSeriesDataItem.period != null) {
158 return false;
159 }
160
161 if (this.value != null) {
162 if (!this.value.equals(timeSeriesDataItem.value)) {
163 return false;
164 }
165 }
166 else if (timeSeriesDataItem.value != null) {
167 return false;
168 }
169
170 return true;
171 }
172
173 /**
174 * Returns a hash code.
175 *
176 * @return A hash code.
177 */
178 public int hashCode() {
179 int result;
180 result = (this.period != null ? this.period.hashCode() : 0);
181 result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
182 return result;
183 }
184
185 /**
186 * Returns an integer indicating the order of this data pair object
187 * relative to another object.
188 * <P>
189 * For the order we consider only the timing:
190 * negative == before, zero == same, positive == after.
191 *
192 * @param o1 The object being compared to.
193 *
194 * @return An integer indicating the order of the data item object
195 * relative to another object.
196 */
197 public int compareTo(Object o1) {
198
199 int result;
200
201 // CASE 1 : Comparing to another TimeSeriesDataItem object
202 // -------------------------------------------------------
203 if (o1 instanceof TimeSeriesDataItem) {
204 TimeSeriesDataItem datapair = (TimeSeriesDataItem) o1;
205 result = getPeriod().compareTo(datapair.getPeriod());
206 }
207
208 // CASE 2 : Comparing to a general object
209 // ---------------------------------------------
210 else {
211 // consider time periods to be ordered after general objects
212 result = 1;
213 }
214
215 return result;
216
217 }
218
219 /**
220 * Clones the data item. Note: there is no need to clone the period or
221 * value since they are immutable classes.
222 *
223 * @return A clone of the data item.
224 */
225 public Object clone() {
226 Object clone = null;
227 try {
228 clone = super.clone();
229 }
230 catch (CloneNotSupportedException e) { // won't get here...
231 e.printStackTrace();
232 }
233 return clone;
234 }
235
236 }