1 /*
2 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.util.calendar;
27
28 import java.util.TimeZone;
29 import java.util.concurrent.ConcurrentHashMap;
30 import java.util.concurrent.ConcurrentMap;
31
32 /**
33 * <code>CalendarSystem</code> is an abstract class that defines the
34 * programming interface to deal with calendar date and time.
35 *
36 * <p><code>CalendarSystem</code> instances are singletons. For
37 * example, there exists only one Gregorian calendar instance in the
38 * Java runtime environment. A singleton instance can be obtained
39 * calling one of the static factory methods.
40 *
41 * <h4>CalendarDate</h4>
42 *
43 * <p>For the methods in a <code>CalendarSystem</code> that manipulate
44 * a <code>CalendarDate</code>, <code>CalendarDate</code>s that have
45 * been created by the <code>CalendarSystem</code> must be
46 * specified. Otherwise, the methods throw an exception. This is
47 * because, for example, a Chinese calendar date can't be understood
48 * by the Hebrew calendar system.
49 *
50 * <h4>Calendar names</h4>
51 *
52 * Each calendar system has a unique name to be identified. The Java
53 * runtime in this release supports the following calendar systems.
54 *
55 * <pre>
56 * Name Calendar System
57 * ---------------------------------------
58 * gregorian Gregorian Calendar
59 * julian Julian Calendar
60 * japanese Japanese Imperial Calendar
61 * </pre>
62 *
63 * @see CalendarDate
64 * @author Masayoshi Okutsu
65 * @since 1.5
66 */
67
68 public abstract class CalendarSystem {
69
70 /////////////////////// Calendar Factory Methods /////////////////////////
71
72 private static volatile boolean initialized;
73
74 // Map of calendar names and calendar class names
75 private static ConcurrentMap<String, String> names;
76
77 // Map of calendar names and CalendarSystem instances
78 private static ConcurrentMap<String,CalendarSystem> calendars;
79
80 private static final String PACKAGE_NAME = "sun.util.calendar.";
81
82 private static final String[] namePairs = {
83 "gregorian", "Gregorian",
84 "japanese", "LocalGregorianCalendar",
85 "julian", "JulianCalendar",
86 /*
87 "hebrew", "HebrewCalendar",
88 "iso8601", "ISOCalendar",
89 "taiwanese", "LocalGregorianCalendar",
90 "thaibuddhist", "LocalGregorianCalendar",
91 */
92 };
93
94 private static void initNames() {
95 ConcurrentMap<String,String> nameMap = new ConcurrentHashMap<>();
96
97 // Associate a calendar name with its class name and the
98 // calendar class name with its date class name.
99 StringBuilder clName = new StringBuilder();
100 for (int i = 0; i < namePairs.length; i += 2) {
101 clName.setLength(0);
102 String cl = clName.append(PACKAGE_NAME).append(namePairs[i+1]).toString();
103 nameMap.put(namePairs[i], cl);
104 }
105 synchronized (CalendarSystem.class) {
106 if (!initialized) {
107 names = nameMap;
108 calendars = new ConcurrentHashMap<>();
109 initialized = true;
110 }
111 }
112 }
113
114 private static final Gregorian GREGORIAN_INSTANCE = new Gregorian();
115
116 /**
117 * Returns the singleton instance of the <code>Gregorian</code>
118 * calendar system.
119 *
120 * @return the <code>Gregorian</code> instance
121 */
122 public static Gregorian getGregorianCalendar() {
123 return GREGORIAN_INSTANCE;
124 }
125
126 /**
127 * Returns a <code>CalendarSystem</code> specified by the calendar
128 * name. The calendar name has to be one of the supported calendar
129 * names.
130 *
131 * @param calendarName the calendar name
132 * @return the <code>CalendarSystem</code> specified by
133 * <code>calendarName</code>, or null if there is no
134 * <code>CalendarSystem</code> associated with the given calendar name.
135 */
136 public static CalendarSystem forName(String calendarName) {
137 if ("gregorian".equals(calendarName)) {
138 return GREGORIAN_INSTANCE;
139 }
140
141 if (!initialized) {
142 initNames();
143 }
144
145 CalendarSystem cal = calendars.get(calendarName);
146 if (cal != null) {
147 return cal;
148 }
149
150 String className = names.get(calendarName);
151 if (className == null) {
152 return null; // Unknown calendar name
153 }
154
155 if (className.endsWith("LocalGregorianCalendar")) {
156 // Create the specific kind of local Gregorian calendar system
157 cal = LocalGregorianCalendar.getLocalGregorianCalendar(calendarName);
158 } else {
159 try {
160 Class<?> cl = Class.forName(className);
161 cal = (CalendarSystem) cl.newInstance();
162 } catch (Exception e) {
163 throw new InternalError(e);
164 }
165 }
166 if (cal == null) {
167 return null;
168 }
169 CalendarSystem cs = calendars.putIfAbsent(calendarName, cal);
170 return (cs == null) ? cal : cs;
171 }
172
173 //////////////////////////////// Calendar API //////////////////////////////////
174
175 /**
176 * Returns the name of this calendar system.
177 */
178 public abstract String getName();
179
180 public abstract CalendarDate getCalendarDate();
181
182 /**
183 * Calculates calendar fields from the specified number of
184 * milliseconds since the Epoch, January 1, 1970 00:00:00 UTC
185 * (Gregorian). This method doesn't check overflow or underflow
186 * when adjusting the millisecond value (representing UTC) with
187 * the time zone offsets (i.e., the GMT offset and amount of
188 * daylight saving).
189 *
190 * @param millis the offset value in milliseconds from January 1,
191 * 1970 00:00:00 UTC (Gregorian).
192 * @return a <code>CalendarDate</code> instance that contains the
193 * calculated calendar field values.
194 */
195 public abstract CalendarDate getCalendarDate(long millis);
196
197 public abstract CalendarDate getCalendarDate(long millis, CalendarDate date);
198
199 public abstract CalendarDate getCalendarDate(long millis, TimeZone zone);
200
201 /**
202 * Constructs a <code>CalendarDate</code> that is specific to this
203 * calendar system. All calendar fields have their initial
204 * values. The {@link TimeZone#getDefault() default time zone} is
205 * set to the instance.
206 *
207 * @return a <code>CalendarDate</code> instance that contains the initial
208 * calendar field values.
209 */
210 public abstract CalendarDate newCalendarDate();
211
212 public abstract CalendarDate newCalendarDate(TimeZone zone);
213
214 /**
215 * Returns the number of milliseconds since the Epoch, January 1,
216 * 1970 00:00:00 UTC (Gregorian), represented by the specified
217 * <code>CalendarDate</code>.
218 *
219 * @param date the <code>CalendarDate</code> from which the time
220 * value is calculated
221 * @return the number of milliseconds since the Epoch.
222 */
223 public abstract long getTime(CalendarDate date);
224
225 /**
226 * Returns the length in days of the specified year by
227 * <code>date</code>. This method does not perform the
228 * normalization with the specified <code>CalendarDate</code>. The
229 * <code>CalendarDate</code> must be normalized to get a correct
230 * value.
231 */
232 public abstract int getYearLength(CalendarDate date);
233
234 /**
235 * Returns the number of months of the specified year. This method
236 * does not perform the normalization with the specified
237 * <code>CalendarDate</code>. The <code>CalendarDate</code> must
238 * be normalized to get a correct value.
239 */
240 public abstract int getYearLengthInMonths(CalendarDate date);
241
242 /**
243 * Returns the length in days of the month specified by the calendar
244 * date. This method does not perform the normalization with the
245 * specified calendar date. The <code>CalendarDate</code> must
246 * be normalized to get a correct value.
247 *
248 * @param date the date from which the month value is obtained
249 * @return the number of days in the month
250 * @exception IllegalArgumentException if the specified calendar date
251 * doesn't have a valid month value in this calendar system.
252 */
253 public abstract int getMonthLength(CalendarDate date); // no setter
254
255 /**
256 * Returns the length in days of a week in this calendar
257 * system. If this calendar system has multiple radix weeks, this
258 * method returns only one of them.
259 */
260 public abstract int getWeekLength();
261
262 /**
263 * Returns the <code>Era</code> designated by the era name that
264 * has to be known to this calendar system. If no Era is
265 * applicable to this calendar system, null is returned.
266 *
267 * @param eraName the name of the era
268 * @return the <code>Era</code> designated by
269 * <code>eraName</code>, or <code>null</code> if no Era is
270 * applicable to this calendar system or the specified era name is
271 * not known to this calendar system.
272 */
273 public abstract Era getEra(String eraName);
274
275 /**
276 * Returns valid <code>Era</code>s of this calendar system. The
277 * return value is sorted in the descendant order. (i.e., the first
278 * element of the returned array is the oldest era.) If no era is
279 * applicable to this calendar system, <code>null</code> is returned.
280 *
281 * @return an array of valid <code>Era</code>s, or
282 * <code>null</code> if no era is applicable to this calendar
283 * system.
284 */
285 public abstract Era[] getEras();
286
287 /**
288 * @throws IllegalArgumentException if the specified era name is
289 * unknown to this calendar system.
290 * @see Era
291 */
292 public abstract void setEra(CalendarDate date, String eraName);
293
294 /**
295 * Returns a <code>CalendarDate</code> of the n-th day of week
296 * which is on, after or before the specified date. For example, the
297 * first Sunday in April 2002 (Gregorian) can be obtained as
298 * below:
299 *
300 * <pre><code>
301 * Gregorian cal = CalendarSystem.getGregorianCalendar();
302 * CalendarDate date = cal.newCalendarDate();
303 * date.setDate(2004, cal.APRIL, 1);
304 * CalendarDate firstSun = cal.getNthDayOfWeek(1, cal.SUNDAY, date);
305 * // firstSun represents April 4, 2004.
306 * </code></pre>
307 *
308 * This method returns a new <code>CalendarDate</code> instance
309 * and doesn't modify the original date.
310 *
311 * @param nth specifies the n-th one. A positive number specifies
312 * <em>on or after</em> the <code>date</code>. A non-positive number
313 * specifies <em>on or before</em> the <code>date</code>.
314 * @param dayOfWeek the day of week
315 * @param date the date
316 * @return the date of the nth <code>dayOfWeek</code> after
317 * or before the specified <code>CalendarDate</code>
318 */
319 public abstract CalendarDate getNthDayOfWeek(int nth, int dayOfWeek,
320 CalendarDate date);
321
322 public abstract CalendarDate setTimeOfDay(CalendarDate date, int timeOfDay);
323
324 /**
325 * Checks whether the calendar fields specified by <code>date</code>
326 * represents a valid date and time in this calendar system. If the
327 * given date is valid, <code>date</code> is marked as <em>normalized</em>.
328 *
329 * @param date the <code>CalendarDate</code> to be validated
330 * @return <code>true</code> if all the calendar fields are consistent,
331 * otherwise, <code>false</code> is returned.
332 * @exception NullPointerException if the specified
333 * <code>date</code> is <code>null</code>
334 */
335 public abstract boolean validate(CalendarDate date);
336
337 /**
338 * Normalizes calendar fields in the specified
339 * <code>date</code>. Also all {@link CalendarDate#FIELD_UNDEFINED
340 * undefined} fields are set to correct values. The actual
341 * normalization process is calendar system dependent.
342 *
343 * @param date the calendar date to be validated
344 * @return <code>true</code> if all fields have been normalized;
345 * <code>false</code> otherwise.
346 * @exception NullPointerException if the specified
347 * <code>date</code> is <code>null</code>
348 */
349 public abstract boolean normalize(CalendarDate date);
350 }