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 * SimpleTimePeriod.java 029 * --------------------- 030 * (C) Copyright 2002-2005, by Object Refinery Limited and Contributors. 031 * 032 * Original Author: David Gilbert (for Object Refinery Limited); 033 * Contributor(s): -; 034 * 035 * $Id: SimpleTimePeriod.java,v 1.5.2.1 2005/10/25 21:35:24 mungady Exp $ 036 * 037 * Changes 038 * ------- 039 * 07-Oct-2002 : Added Javadocs (DG); 040 * 10-Jan-2003 : Renamed TimeAllocation --> SimpleTimePeriod (DG); 041 * 13-Mar-2003 : Added equals() method, and Serializable interface (DG); 042 * 21-Oct-2003 : Added hashCode() method (DG); 043 * 27-Jan-2005 : Implemented Comparable, to enable this class to be used 044 * in the TimeTableXYDataset class (DG); 045 * 046 */ 047 048 package org.jfree.data.time; 049 050 import java.io.Serializable; 051 import java.util.Date; 052 053 /** 054 * An arbitrary period of time, measured to millisecond precision using 055 * <code>java.util.Date</code>. 056 * <p> 057 * This class is intentionally immutable (that is, once constructed, you cannot 058 * alter the start and end attributes). 059 */ 060 public class SimpleTimePeriod implements TimePeriod, Comparable, Serializable { 061 062 /** For serialization. */ 063 private static final long serialVersionUID = 8684672361131829554L; 064 065 /** The start date/time. */ 066 private Date start; 067 068 /** The end date/time. */ 069 private Date end; 070 071 /** 072 * Creates a new time allocation. 073 * 074 * @param start the start date/time in milliseconds. 075 * @param end the end date/time in milliseconds. 076 */ 077 public SimpleTimePeriod(long start, long end) { 078 this(new Date(start), new Date(end)); 079 } 080 081 /** 082 * Creates a new time allocation. 083 * 084 * @param start the start date/time (<code>null</code> not permitted). 085 * @param end the end date/time (<code>null</code> not permitted). 086 */ 087 public SimpleTimePeriod(Date start, Date end) { 088 if (start.getTime() > end.getTime()) { 089 throw new IllegalArgumentException("Requires end >= start."); 090 } 091 this.start = start; 092 this.end = end; 093 } 094 095 /** 096 * Returns the start date/time. 097 * 098 * @return The start date/time (never <code>null</code>). 099 */ 100 public Date getStart() { 101 return this.start; 102 } 103 104 /** 105 * Returns the end date/time. 106 * 107 * @return The end date/time (never <code>null</code>). 108 */ 109 public Date getEnd() { 110 return this.end; 111 } 112 113 /** 114 * Tests this time period instance for equality with an arbitrary object. 115 * The object is considered equal if it is an instance of {@link TimePeriod} 116 * and it has the same start and end dates. 117 * 118 * @param obj the other object (<code>null</code> permitted). 119 * 120 * @return A boolean. 121 */ 122 public boolean equals(Object obj) { 123 if (obj == this) { 124 return true; 125 } 126 if (!(obj instanceof TimePeriod)) { 127 return false; 128 } 129 TimePeriod that = (TimePeriod) obj; 130 if (!this.start.equals(that.getStart())) { 131 return false; 132 } 133 if (!this.end.equals(that.getEnd())) { 134 return false; 135 } 136 return true; 137 } 138 139 /** 140 * Returns an integer that indicates the relative ordering of two 141 * time periods. 142 * 143 * @param obj the object (<code>null</code> not permitted). 144 * 145 * @return An integer. 146 * 147 * @throws ClassCastException if <code>obj</code> is not an instance of 148 * {@link TimePeriod}. 149 */ 150 public int compareTo(Object obj) { 151 TimePeriod that = (TimePeriod) obj; 152 long t0 = getStart().getTime(); 153 long t1 = getEnd().getTime(); 154 long m0 = t0 + (t1 - t0) / 2L; 155 long t2 = that.getStart().getTime(); 156 long t3 = that.getEnd().getTime(); 157 long m1 = t2 + (t3 - t2) / 2L; 158 if (m0 < m1) { 159 return -1; 160 } 161 else if (m0 > m1) { 162 return 1; 163 } 164 else { 165 if (t0 < t2) { 166 return -1; 167 } 168 else if (t0 > t2) { 169 return 1; 170 } 171 else { 172 if (t1 < t3) { 173 return -1; 174 } 175 else if (t1 > t3) { 176 return 1; 177 } 178 else { 179 return 0; 180 } 181 } 182 } 183 } 184 185 /** 186 * Returns a hash code for this object instance. The approach described by 187 * Joshua Bloch in "Effective Java" has been used here - see: 188 * <p> 189 * <code>http://developer.java.sun.com/ 190 * developer/Books/effectivejava/Chapter3.pdf</code> 191 * 192 * @return A hash code. 193 */ 194 public int hashCode() { 195 int result = 17; 196 result = 37 * result + this.start.hashCode(); 197 result = 37 * result + this.end.hashCode(); 198 return result; 199 } 200 201 }