Source for org.jfree.data.time.Year

   1: /* ===========================================================
   2:  * JFreeChart : a free chart library for the Java(tm) platform
   3:  * ===========================================================
   4:  *
   5:  * (C) Copyright 2000-2006, by Object Refinery Limited and Contributors.
   6:  *
   7:  * Project Info:  http://www.jfree.org/jfreechart/index.html
   8:  *
   9:  * This library is free software; you can redistribute it and/or modify it 
  10:  * under the terms of the GNU Lesser General Public License as published by 
  11:  * the Free Software Foundation; either version 2.1 of the License, or 
  12:  * (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but 
  15:  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
  16:  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
  17:  * License for more details.
  18:  *
  19:  * You should have received a copy of the GNU Lesser General Public
  20:  * License along with this library; if not, write to the Free Software
  21:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
  22:  * USA.  
  23:  *
  24:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
  25:  * in the United States and other countries.]
  26:  *
  27:  * ---------
  28:  * Year.java
  29:  * ---------
  30:  * (C) Copyright 2001-2006, by Object Refinery Limited.
  31:  *
  32:  * Original Author:  David Gilbert (for Object Refinery Limited);
  33:  * Contributor(s):   -;
  34:  *
  35:  * $Id: Year.java,v 1.9.2.4 2006/10/06 14:00:16 mungady Exp $
  36:  *
  37:  * Changes
  38:  * -------
  39:  * 11-Oct-2001 : Version 1 (DG);
  40:  * 14-Nov-2001 : Override for toString() method (DG);
  41:  * 19-Dec-2001 : Added a new constructor as suggested by Paul English (DG);
  42:  * 29-Jan-2002 : Worked on parseYear() method (DG);
  43:  * 14-Feb-2002 : Fixed bug in Year(Date) constructor (DG);
  44:  * 26-Feb-2002 : Changed getStart(), getMiddle() and getEnd() methods to 
  45:  *               evaluate with reference to a particular time zone (DG);
  46:  * 19-Mar-2002 : Changed API for TimePeriod classes (DG);
  47:  * 10-Sep-2002 : Added getSerialIndex() method (DG);
  48:  * 04-Oct-2002 : Fixed errors reported by Checkstyle (DG);
  49:  * 10-Jan-2003 : Changed base class and method names (DG);
  50:  * 05-Mar-2003 : Fixed bug in getFirstMillisecond() picked up in JUnit 
  51:  *               tests (DG);
  52:  * 13-Mar-2003 : Moved to com.jrefinery.data.time package, and implemented 
  53:  *               Serializable (DG);
  54:  * 21-Oct-2003 : Added hashCode() method (DG);
  55:  * ------------- JFREECHART 1.0.x ---------------------------------------------
  56:  * 05-Oct-2006 : Updated API docs (DG);
  57:  * 06-Oct-2006 : Refactored to cache first and last millisecond values (DG);
  58:  * 
  59:  */
  60: 
  61: package org.jfree.data.time;
  62: 
  63: import java.io.Serializable;
  64: import java.util.Calendar;
  65: import java.util.Date;
  66: import java.util.TimeZone;
  67: 
  68: import org.jfree.date.SerialDate;
  69: 
  70: /**
  71:  * Represents a year in the range 1900 to 9999.  This class is immutable, which
  72:  * is a requirement for all {@link RegularTimePeriod} subclasses.
  73:  */
  74: public class Year extends RegularTimePeriod implements Serializable {
  75: 
  76:     /** For serialization. */
  77:     private static final long serialVersionUID = -7659990929736074836L;
  78:     
  79:     /** The year. */
  80:     private short year;
  81: 
  82:     /** The first millisecond. */
  83:     private long firstMillisecond;
  84:     
  85:     /** The last millisecond. */
  86:     private long lastMillisecond;
  87:     
  88:     /**
  89:      * Creates a new <code>Year</code>, based on the current system date/time.
  90:      */
  91:     public Year() {
  92:         this(new Date());
  93:     }
  94: 
  95:     /**
  96:      * Creates a time period representing a single year.
  97:      *
  98:      * @param year  the year.
  99:      */
 100:     public Year(int year) {
 101:         if ((year < SerialDate.MINIMUM_YEAR_SUPPORTED)
 102:             || (year > SerialDate.MAXIMUM_YEAR_SUPPORTED)) {
 103: 
 104:             throw new IllegalArgumentException(
 105:                 "Year constructor: year (" + year + ") outside valid range.");
 106:         }
 107:         this.year = (short) year;
 108:         peg(Calendar.getInstance());
 109:     }
 110: 
 111:     /**
 112:      * Creates a new <code>Year</code>, based on a particular instant in time, 
 113:      * using the default time zone.
 114:      *
 115:      * @param time  the time (<code>null</code> not permitted).
 116:      */
 117:     public Year(Date time) {
 118:         this(time, RegularTimePeriod.DEFAULT_TIME_ZONE);
 119:     }
 120: 
 121:     /**
 122:      * Constructs a year, based on a particular instant in time and a time zone.
 123:      *
 124:      * @param time  the time.
 125:      * @param zone  the time zone.
 126:      */
 127:     public Year(Date time, TimeZone zone) {
 128:         Calendar calendar = Calendar.getInstance(zone);
 129:         calendar.setTime(time);
 130:         this.year = (short) calendar.get(Calendar.YEAR);
 131:         peg(calendar);
 132:     }
 133: 
 134:     /**
 135:      * Returns the year.
 136:      *
 137:      * @return The year.
 138:      */
 139:     public int getYear() {
 140:         return this.year;
 141:     }
 142:     
 143:     /**
 144:      * Returns the first millisecond of the year.  This will be determined 
 145:      * relative to the time zone specified in the constructor, or in the 
 146:      * calendar instance passed in the most recent call to the 
 147:      * {@link #peg(Calendar)} method.
 148:      *
 149:      * @return The first millisecond of the year.
 150:      * 
 151:      * @see #getLastMillisecond()
 152:      */
 153:     public long getFirstMillisecond() {
 154:         return this.firstMillisecond;
 155:     }
 156: 
 157:     /**
 158:      * Returns the last millisecond of the year.  This will be 
 159:      * determined relative to the time zone specified in the constructor, or
 160:      * in the calendar instance passed in the most recent call to the 
 161:      * {@link #peg(Calendar)} method.
 162:      *
 163:      * @return The last millisecond of the year.
 164:      * 
 165:      * @see #getFirstMillisecond()
 166:      */
 167:     public long getLastMillisecond() {
 168:         return this.lastMillisecond;
 169:     }
 170:     
 171:     /** 
 172:      * Recalculates the start date/time and end date/time for this time period 
 173:      * relative to the supplied calendar (which incorporates a time zone).
 174:      * 
 175:      * @param calendar  the calendar (<code>null</code> not permitted).
 176:      * 
 177:      * @since 1.0.3
 178:      */
 179:     public void peg(Calendar calendar) {
 180:         this.firstMillisecond = getFirstMillisecond(calendar);
 181:         this.lastMillisecond = getLastMillisecond(calendar);
 182:     }
 183:     
 184:     /**
 185:      * Returns the year preceding this one.
 186:      *
 187:      * @return The year preceding this one (or <code>null</code> if the 
 188:      *         current year is 1900).
 189:      */
 190:     public RegularTimePeriod previous() {
 191:         if (this.year > SerialDate.MINIMUM_YEAR_SUPPORTED) {
 192:             return new Year(this.year - 1);
 193:         }
 194:         else {
 195:             return null;
 196:         }
 197:     }
 198: 
 199:     /**
 200:      * Returns the year following this one.
 201:      *
 202:      * @return The year following this one (or <code>null</code> if the current
 203:      *         year is 9999).
 204:      */
 205:     public RegularTimePeriod next() {
 206:         if (this.year < SerialDate.MAXIMUM_YEAR_SUPPORTED) {
 207:             return new Year(this.year + 1);
 208:         }
 209:         else {
 210:             return null;
 211:         }
 212:     }
 213: 
 214:     /**
 215:      * Returns a serial index number for the year.
 216:      * <P>
 217:      * The implementation simply returns the year number (e.g. 2002).
 218:      *
 219:      * @return The serial index number.
 220:      */
 221:     public long getSerialIndex() {
 222:         return this.year;
 223:     }
 224: 
 225:     /**
 226:      * Returns the first millisecond of the year, evaluated using the supplied
 227:      * calendar (which determines the time zone).
 228:      *
 229:      * @param calendar  the calendar (<code>null</code> not permitted).
 230:      *
 231:      * @return The first millisecond of the year.
 232:      *
 233:      * @throws NullPointerException if <code>calendar</code> is 
 234:      *     <code>null</code>.
 235:      */
 236:     public long getFirstMillisecond(Calendar calendar) {
 237:         calendar.set(this.year, Calendar.JANUARY, 1, 0, 0, 0);
 238:         calendar.set(Calendar.MILLISECOND, 0);
 239:         // in the following line, we'd rather call calendar.getTimeInMillis()
 240:         // to avoid object creation, but that isn't supported in Java 1.3.1
 241:         return calendar.getTime().getTime();
 242:     }
 243: 
 244:     /**
 245:      * Returns the last millisecond of the year, evaluated using the supplied
 246:      * calendar (which determines the time zone).
 247:      *
 248:      * @param calendar  the calendar (<code>null</code> not permitted).
 249:      *
 250:      * @return The last millisecond of the year.
 251:      *
 252:      * @throws NullPointerException if <code>calendar</code> is 
 253:      *     <code>null</code>.
 254:      */
 255:     public long getLastMillisecond(Calendar calendar) {
 256:         calendar.set(this.year, Calendar.DECEMBER, 31, 23, 59, 59);
 257:         calendar.set(Calendar.MILLISECOND, 999);
 258:         // in the following line, we'd rather call calendar.getTimeInMillis()
 259:         // to avoid object creation, but that isn't supported in Java 1.3.1
 260:         return calendar.getTime().getTime();
 261:     }
 262:     
 263:     /**
 264:      * Tests the equality of this <code>Year</code> object to an arbitrary 
 265:      * object.  Returns <code>true</code> if the target is a <code>Year</code>
 266:      * instance representing the same year as this object.  In all other cases,
 267:      * returns <code>false</code>.
 268:      *
 269:      * @param object  the object (<code>null</code> permitted).
 270:      *
 271:      * @return <code>true</code> if the year of this and the object are the 
 272:      *         same.
 273:      */
 274:     public boolean equals(Object object) {
 275:         if (object != null) {
 276:             if (object instanceof Year) {
 277:                 Year target = (Year) object;
 278:                 return (this.year == target.getYear());
 279:             }
 280:             else {
 281:                 return false;
 282:             }
 283:         }
 284:         else {
 285:             return false;
 286:         }
 287:     }
 288:     
 289:     /**
 290:      * Returns a hash code for this object instance.  The approach described by
 291:      * Joshua Bloch in "Effective Java" has been used here:
 292:      * <p>
 293:      * <code>http://developer.java.sun.com/developer/Books/effectivejava
 294:      *     /Chapter3.pdf</code>
 295:      * 
 296:      * @return A hash code.
 297:      */
 298:     public int hashCode() {
 299:         int result = 17;
 300:         int c = this.year;
 301:         result = 37 * result + c;
 302:         return result;
 303:     }
 304: 
 305:     /**
 306:      * Returns an integer indicating the order of this <code>Year</code> object
 307:      * relative to the specified object:
 308:      *
 309:      * negative == before, zero == same, positive == after.
 310:      *
 311:      * @param o1  the object to compare.
 312:      *
 313:      * @return negative == before, zero == same, positive == after.
 314:      */
 315:     public int compareTo(Object o1) {
 316: 
 317:         int result;
 318: 
 319:         // CASE 1 : Comparing to another Year object
 320:         // -----------------------------------------
 321:         if (o1 instanceof Year) {
 322:             Year y = (Year) o1;
 323:             result = this.year - y.getYear();
 324:         }
 325: 
 326:         // CASE 2 : Comparing to another TimePeriod object
 327:         // -----------------------------------------------
 328:         else if (o1 instanceof RegularTimePeriod) {
 329:             // more difficult case - evaluate later...
 330:             result = 0;
 331:         }
 332: 
 333:         // CASE 3 : Comparing to a non-TimePeriod object
 334:         // ---------------------------------------------
 335:         else {
 336:             // consider time periods to be ordered after general objects
 337:             result = 1;
 338:         }
 339: 
 340:         return result;
 341: 
 342:     }
 343: 
 344:     /**
 345:      * Returns a string representing the year..
 346:      *
 347:      * @return A string representing the year.
 348:      */
 349:     public String toString() {
 350:         return Integer.toString(this.year);
 351:     }
 352: 
 353:     /**
 354:      * Parses the string argument as a year.
 355:      * <P>
 356:      * The string format is YYYY.
 357:      *
 358:      * @param s  a string representing the year.
 359:      *
 360:      * @return <code>null</code> if the string is not parseable, the year 
 361:      *         otherwise.
 362:      */
 363:     public static Year parseYear(String s) {
 364: 
 365:         // parse the string...
 366:         int y;
 367:         try {
 368:             y = Integer.parseInt(s.trim());
 369:         }
 370:         catch (NumberFormatException e) {
 371:             throw new TimePeriodFormatException("Cannot parse string.");
 372:         }
 373: 
 374:         // create the year...
 375:         try {
 376:             return new Year(y);
 377:         }
 378:         catch (IllegalArgumentException e) {
 379:             throw new TimePeriodFormatException("Year outside valid range.");
 380:         }
 381:     }
 382: 
 383: }