001    /* ===========================================================
002     * JFreeChart : a free chart library for the Java(tm) platform
003     * ===========================================================
004     *
005     * (C) Copyright 2000-2011, 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     * [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     * TimeSeriesDataItem.java
029     * -----------------------
030     * (C) Copyright 2001-2009, 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     * ------------- JFREECHART 1.0.x ---------------------------------------------
045     * 09-Jun-2009 : Tidied up equals() (DG);
046     */
047    
048    package org.jfree.data.time;
049    
050    import java.io.Serializable;
051    import org.jfree.util.ObjectUtilities;
052    
053    /**
054     * Represents one data item in a time series.
055     * <P>
056     * The time period can be any of the following:
057     * <ul>
058     * <li>{@link Year}</li>
059     * <li>{@link Quarter}</li>
060     * <li>{@link Month}</li>
061     * <li>{@link Week}</li>
062     * <li>{@link Day}</li>
063     * <li>{@link Hour}</li>
064     * <li>{@link Minute}</li>
065     * <li>{@link Second}</li>
066     * <li>{@link Millisecond}</li>
067     * <li>{@link FixedMillisecond}</li>
068     * </ul>
069     *
070     * The time period is an immutable property of the data item.  Data items will
071     * often be sorted within a list, and allowing the time period to be changed
072     * could destroy the sort order.
073     * <P>
074     * Implements the <code>Comparable</code> interface so that standard Java
075     * sorting can be used to keep the data items in order.
076     *
077     */
078    public class TimeSeriesDataItem implements Cloneable, Comparable, Serializable {
079    
080        /** For serialization. */
081        private static final long serialVersionUID = -2235346966016401302L;
082    
083        /** The time period. */
084        private RegularTimePeriod period;
085    
086        /** The value associated with the time period. */
087        private Number value;
088    
089        /**
090         * Constructs a new data item that associates a value with a time period.
091         *
092         * @param period  the time period (<code>null</code> not permitted).
093         * @param value  the value (<code>null</code> permitted).
094         */
095        public TimeSeriesDataItem(RegularTimePeriod period, Number value) {
096            if (period == null) {
097                throw new IllegalArgumentException("Null 'period' argument.");
098            }
099            this.period = period;
100            this.value = value;
101        }
102    
103        /**
104         * Constructs a new data item that associates a value with a time period.
105         *
106         * @param period  the time period (<code>null</code> not permitted).
107         * @param value  the value associated with the time period.
108         */
109        public TimeSeriesDataItem(RegularTimePeriod period, double value) {
110            this(period, new Double(value));
111        }
112    
113        /**
114         * Returns the time period.
115         *
116         * @return The time period (never <code>null</code>).
117         */
118        public RegularTimePeriod getPeriod() {
119            return this.period;
120        }
121    
122        /**
123         * Returns the value.
124         *
125         * @return The value (<code>null</code> possible).
126         *
127         * @see #setValue(java.lang.Number)
128         */
129        public Number getValue() {
130            return this.value;
131        }
132    
133        /**
134         * Sets the value for this data item.
135         *
136         * @param value  the value (<code>null</code> permitted).
137         *
138         * @see #getValue()
139         */
140        public void setValue(Number value) {
141            this.value = value;
142        }
143    
144        /**
145         * Tests this object for equality with an arbitrary object.
146         *
147         * @param obj  the other object (<code>null</code> permitted).
148         *
149         * @return A boolean.
150         */
151        public boolean equals(Object obj) {
152            if (this == obj) {
153                return true;
154            }
155            if (!(obj instanceof TimeSeriesDataItem)) {
156                return false;
157            }
158            TimeSeriesDataItem that = (TimeSeriesDataItem) obj;
159            if (!ObjectUtilities.equal(this.period, that.period)) {
160                return false;
161            }
162            if (!ObjectUtilities.equal(this.value, that.value)) {
163                return false;
164            }
165            return true;
166        }
167    
168        /**
169         * Returns a hash code.
170         *
171         * @return A hash code.
172         */
173        public int hashCode() {
174            int result;
175            result = (this.period != null ? this.period.hashCode() : 0);
176            result = 29 * result + (this.value != null ? this.value.hashCode() : 0);
177            return result;
178        }
179    
180        /**
181         * Returns an integer indicating the order of this data pair object
182         * relative to another object.
183         * <P>
184         * For the order we consider only the timing:
185         * negative == before, zero == same, positive == after.
186         *
187         * @param o1  The object being compared to.
188         *
189         * @return An integer indicating the order of the data item object
190         *         relative to another object.
191         */
192        public int compareTo(Object o1) {
193    
194            int result;
195    
196            // CASE 1 : Comparing to another TimeSeriesDataItem object
197            // -------------------------------------------------------
198            if (o1 instanceof TimeSeriesDataItem) {
199                TimeSeriesDataItem datapair = (TimeSeriesDataItem) o1;
200                result = getPeriod().compareTo(datapair.getPeriod());
201            }
202    
203            // CASE 2 : Comparing to a general object
204            // ---------------------------------------------
205            else {
206                // consider time periods to be ordered after general objects
207                result = 1;
208            }
209    
210            return result;
211    
212        }
213    
214        /**
215         * Clones the data item.  Note: there is no need to clone the period or
216         * value since they are immutable classes.
217         *
218         * @return A clone of the data item.
219         */
220        public Object clone() {
221            Object clone = null;
222            try {
223                clone = super.clone();
224            }
225            catch (CloneNotSupportedException e) { // won't get here...
226                e.printStackTrace();
227            }
228            return clone;
229        }
230    
231    }