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
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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 @SuppressWarnings("deprecation")
161 Object tmp = Class.forName(className).newInstance();
162 cal = (CalendarSystem) tmp;
163 } catch (Exception e) {
164 throw new InternalError(e);
165 }
166 }
167 if (cal == null) {
168 return null;
169 }
170 CalendarSystem cs = calendars.putIfAbsent(calendarName, cal);
171 return (cs == null) ? cal : cs;
172 }
173
174 //////////////////////////////// Calendar API //////////////////////////////////
175
176 /**
177 * Returns the name of this calendar system.
178 */
179 public abstract String getName();
180
181 public abstract CalendarDate getCalendarDate();
182
183 /**
184 * Calculates calendar fields from the specified number of
185 * milliseconds since the Epoch, January 1, 1970 00:00:00 UTC
186 * (Gregorian). This method doesn't check overflow or underflow
187 * when adjusting the millisecond value (representing UTC) with
188 * the time zone offsets (i.e., the GMT offset and amount of
189 * daylight saving).
190 *
191 * @param millis the offset value in milliseconds from January 1,
192 * 1970 00:00:00 UTC (Gregorian).
193 * @return a <code>CalendarDate</code> instance that contains the
194 * calculated calendar field values.
195 */
196 public abstract CalendarDate getCalendarDate(long millis);
197
198 public abstract CalendarDate getCalendarDate(long millis, CalendarDate date);
199
200 public abstract CalendarDate getCalendarDate(long millis, TimeZone zone);
201
202 /**
203 * Constructs a <code>CalendarDate</code> that is specific to this
204 * calendar system. All calendar fields have their initial
205 * values. The {@link TimeZone#getDefault() default time zone} is
206 * set to the instance.
207 *
208 * @return a <code>CalendarDate</code> instance that contains the initial
209 * calendar field values.
210 */
211 public abstract CalendarDate newCalendarDate();
212
213 public abstract CalendarDate newCalendarDate(TimeZone zone);
214
215 /**
216 * Returns the number of milliseconds since the Epoch, January 1,
217 * 1970 00:00:00 UTC (Gregorian), represented by the specified
218 * <code>CalendarDate</code>.
219 *
220 * @param date the <code>CalendarDate</code> from which the time
221 * value is calculated
222 * @return the number of milliseconds since the Epoch.
223 */
224 public abstract long getTime(CalendarDate date);
225
226 /**
227 * Returns the length in days of the specified year by
228 * <code>date</code>. This method does not perform the
229 * normalization with the specified <code>CalendarDate</code>. The
230 * <code>CalendarDate</code> must be normalized to get a correct
231 * value.
232 */
233 public abstract int getYearLength(CalendarDate date);
234
235 /**
236 * Returns the number of months of the specified year. This method
237 * does not perform the normalization with the specified
238 * <code>CalendarDate</code>. The <code>CalendarDate</code> must
239 * be normalized to get a correct value.
240 */
241 public abstract int getYearLengthInMonths(CalendarDate date);
242
243 /**
244 * Returns the length in days of the month specified by the calendar
245 * date. This method does not perform the normalization with the
246 * specified calendar date. The <code>CalendarDate</code> must
247 * be normalized to get a correct value.
248 *
249 * @param date the date from which the month value is obtained
250 * @return the number of days in the month
251 * @exception IllegalArgumentException if the specified calendar date
252 * doesn't have a valid month value in this calendar system.
253 */
254 public abstract int getMonthLength(CalendarDate date); // no setter
255
256 /**
257 * Returns the length in days of a week in this calendar
258 * system. If this calendar system has multiple radix weeks, this
259 * method returns only one of them.
260 */
261 public abstract int getWeekLength();
262
263 /**
264 * Returns the <code>Era</code> designated by the era name that
265 * has to be known to this calendar system. If no Era is
266 * applicable to this calendar system, null is returned.
267 *
268 * @param eraName the name of the era
269 * @return the <code>Era</code> designated by
270 * <code>eraName</code>, or <code>null</code> if no Era is
271 * applicable to this calendar system or the specified era name is
272 * not known to this calendar system.
273 */
274 public abstract Era getEra(String eraName);
275
276 /**
277 * Returns valid <code>Era</code>s of this calendar system. The
278 * return value is sorted in the descendant order. (i.e., the first
279 * element of the returned array is the oldest era.) If no era is
280 * applicable to this calendar system, <code>null</code> is returned.
281 *
282 * @return an array of valid <code>Era</code>s, or
283 * <code>null</code> if no era is applicable to this calendar
284 * system.
285 */
286 public abstract Era[] getEras();
287
288 /**
289 * @throws IllegalArgumentException if the specified era name is
290 * unknown to this calendar system.
291 * @see Era
292 */
293 public abstract void setEra(CalendarDate date, String eraName);
294
295 /**
296 * Returns a <code>CalendarDate</code> of the n-th day of week
297 * which is on, after or before the specified date. For example, the
298 * first Sunday in April 2002 (Gregorian) can be obtained as
299 * below:
300 *
301 * <pre><code>
302 * Gregorian cal = CalendarSystem.getGregorianCalendar();
303 * CalendarDate date = cal.newCalendarDate();
304 * date.setDate(2004, cal.APRIL, 1);
305 * CalendarDate firstSun = cal.getNthDayOfWeek(1, cal.SUNDAY, date);
306 * // firstSun represents April 4, 2004.
307 * </code></pre>
308 *
309 * This method returns a new <code>CalendarDate</code> instance
310 * and doesn't modify the original date.
311 *
312 * @param nth specifies the n-th one. A positive number specifies
313 * <em>on or after</em> the <code>date</code>. A non-positive number
314 * specifies <em>on or before</em> the <code>date</code>.
315 * @param dayOfWeek the day of week
316 * @param date the date
317 * @return the date of the nth <code>dayOfWeek</code> after
318 * or before the specified <code>CalendarDate</code>
319 */
320 public abstract CalendarDate getNthDayOfWeek(int nth, int dayOfWeek,
321 CalendarDate date);
322
323 public abstract CalendarDate setTimeOfDay(CalendarDate date, int timeOfDay);
324
325 /**
326 * Checks whether the calendar fields specified by <code>date</code>
327 * represents a valid date and time in this calendar system. If the
328 * given date is valid, <code>date</code> is marked as <em>normalized</em>.
329 *
330 * @param date the <code>CalendarDate</code> to be validated
331 * @return <code>true</code> if all the calendar fields are consistent,
332 * otherwise, <code>false</code> is returned.
333 * @exception NullPointerException if the specified
334 * <code>date</code> is <code>null</code>
335 */
336 public abstract boolean validate(CalendarDate date);
337
338 /**
339 * Normalizes calendar fields in the specified
340 * <code>date</code>. Also all {@link CalendarDate#FIELD_UNDEFINED
341 * undefined} fields are set to correct values. The actual
342 * normalization process is calendar system dependent.
343 *
344 * @param date the calendar date to be validated
345 * @return <code>true</code> if all fields have been normalized;
346 * <code>false</code> otherwise.
347 * @exception NullPointerException if the specified
348 * <code>date</code> is <code>null</code>
349 */
350 public abstract boolean normalize(CalendarDate date);
351 }