    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 * SimpleTimePeriod.java
    029 * ---------------------
    030 * (C) Copyright 2002-2008, by Object Refinery Limited and Contributors.
    031 *
    032 * Original Author:  David Gilbert (for Object Refinery Limited);
    033 * Contributor(s):   -;
    034 *
    035 * Changes
    036 * -------
    037 * 07-Oct-2002 : Added Javadocs (DG);
    038 * 10-Jan-2003 : Renamed TimeAllocation --> SimpleTimePeriod (DG);
    039 * 13-Mar-2003 : Added equals() method, and Serializable interface (DG);
    040 * 21-Oct-2003 : Added hashCode() method (DG);
    041 * 27-Jan-2005 : Implemented Comparable, to enable this class to be used
    042 *               in the TimeTableXYDataset class (DG);
    043 * 02-Jun-2008 : Fixed problem with fields being mutable (DG);
    044 *
    045 */
    046
    047package org.jfree.data.time;
    048
    049import java.io.Serializable;
    050import java.util.Date;
    051
    052/**
    053 * An arbitrary period of time, measured to millisecond precision using
    054 * <code>java.util.Date</code>.
    055 * <p>
    056 * This class is intentionally immutable (that is, once constructed, you cannot
    057 * alter the start and end attributes).
    058 */
    059public class SimpleTimePeriod implements TimePeriod, Comparable, Serializable {
    060
    061    /** For serialization. */
    062    private static final long serialVersionUID = 8684672361131829554L;
    063
    064    /** The start date/time. */
    065    private long start;
    066
    067    /** The end date/time. */
    068    private long end;
    069
    070    /**
    071     * Creates a new time allocation.
    072     *
    073     * @param start  the start date/time in milliseconds.
    074     * @param end  the end date/time in milliseconds.
    075     */
    076    public SimpleTimePeriod(long start, long end) {
    077        if (start > end) {
    078            throw new IllegalArgumentException("Requires start <= end.");
    079        }
    080        this.start = start;
    081        this.end = end;
    082    }
    083
    084    /**
    085     * Creates a new time allocation.
    086     *
    087     * @param start  the start date/time (<code>null</code> not permitted).
    088     * @param end  the end date/time (<code>null</code> not permitted).
    089     */
    090    public SimpleTimePeriod(Date start, Date end) {
    091        this(start.getTime(), end.getTime());
    092    }
    093
    094    /**
    095     * Returns the start date/time.
    096     *
    097     * @return The start date/time (never <code>null</code>).
    098     */
    099    public Date getStart() {
    100        return new Date(this.start);
    101    }
    102
    103    /**
    104     * Returns the start date/time in milliseconds.
    105     *
    106     * @return The start.
    107     *
    108     * @since 1.0.10.
    109     */
    110    public long getStartMillis() {
    111        return this.start;
    112    }
    113
    114    /**
    115     * Returns the end date/time.
    116     *
    117     * @return The end date/time (never <code>null</code>).
    118     */
    119    public Date getEnd() {
    120        return new Date(this.end);
    121    }
    122
    123    /**
    124     * Returns the end date/time in milliseconds.
    125     *
    126     * @return The end.
    127     *
    128     * @since 1.0.10.
    129     */
    130    public long getEndMillis() {
    131        return this.end;
    132    }
    133
    134    /**
    135     * Tests this time period instance for equality with an arbitrary object.
    136     * The object is considered equal if it is an instance of {@link TimePeriod}
    137     * and it has the same start and end dates.
    138     *
    139     * @param obj  the other object (<code>null</code> permitted).
    140     *
    141     * @return A boolean.
    142     */
    143    public boolean equals(Object obj) {
    144        if (obj == this) {
    145            return true;
    146        }
    147        if (!(obj instanceof TimePeriod)) {
    148            return false;
    149        }
    150        TimePeriod that = (TimePeriod) obj;
    151        if (!this.getStart().equals(that.getStart())) {
    152            return false;
    153        }
    154        if (!this.getEnd().equals(that.getEnd())) {
    155            return false;
    156        }
    157        return true;
    158    }
    159
    160    /**
    161     * Returns an integer that indicates the relative ordering of two
    162     * time periods.
    163     *
    164     * @param obj  the object (<code>null</code> not permitted).
    165     *
    166     * @return An integer.
    167     *
    168     * @throws ClassCastException if <code>obj</code> is not an instance of
    169     *                            {@link TimePeriod}.
    170     */
    171    public int compareTo(Object obj) {
    172        TimePeriod that = (TimePeriod) obj;
    173        long t0 = getStart().getTime();
    174        long t1 = getEnd().getTime();
    175        long m0 = t0 + (t1 - t0) / 2L;
    176        long t2 = that.getStart().getTime();
    177        long t3 = that.getEnd().getTime();
    178        long m1 = t2 + (t3 - t2) / 2L;
    179        if (m0 < m1) {
    180            return -1;
    181        }
    182        else if (m0 > m1) {
    183            return 1;
    184        }
    185        else {
    186            if (t0 < t2) {
    187                return -1;
    188            }
    189            else if (t0 > t2) {
    190                return 1;
    191            }
    192            else {
    193                if (t1 < t3) {
    194                    return -1;
    195                }
    196                else if (t1 > t3) {
    197                    return 1;
    198                }
    199                else {
    200                    return 0;
    201                }
    202            }
    203        }
    204    }
    205
    206    /**
    207     * Returns a hash code for this object instance.  The approach described by
    208     * Joshua Bloch in "Effective Java" has been used here - see:
    209     * <p>
    210     * <code>http://developer.java.sun.com/
    211     * developer/Books/effectivejava/Chapter3.pdf</code>
    212     *
    213     * @return A hash code.
    214     */
    215    public int hashCode() {
    216        int result = 17;
    217        result = 37 * result + (int) this.start;
    218        result = 37 * result + (int) this.end;
    219        return result;
    220    }
    221
    222}