jdk/src/share/classes/java/time/temporal/ISOChrono.java
changeset 15289 3ac550392e43
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/time/temporal/ISOChrono.java	Tue Jan 22 20:59:21 2013 -0800
@@ -0,0 +1,399 @@
+/*
+ * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ *  * Neither the name of JSR-310 nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package java.time.temporal;
+
+import java.io.Serializable;
+import java.time.Clock;
+import java.time.DateTimeException;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Locale;
+import java.util.Objects;
+
+/**
+ * The ISO calendar system.
+ * <p>
+ * This chronology defines the rules of the ISO calendar system.
+ * This calendar system is based on the ISO-8601 standard, which is the
+ * <i>de facto</i> world calendar.
+ * <p>
+ * The fields are defined as follows:
+ * <p><ul>
+ * <li>era - There are two eras, 'Current Era' (CE) and 'Before Current Era' (BCE).
+ * <li>year-of-era - The year-of-era is the same as the proleptic-year for the current CE era.
+ *  For the BCE era before the ISO epoch the year increases from 1 upwards as time goes backwards.
+ * <li>proleptic-year - The proleptic year is the same as the year-of-era for the
+ *  current era. For the previous era, years have zero, then negative values.
+ * <li>month-of-year - There are 12 months in an ISO year, numbered from 1 to 12.
+ * <li>day-of-month - There are between 28 and 31 days in each of the ISO month, numbered from 1 to 31.
+ *  Months 4, 6, 9 and 11 have 30 days, Months 1, 3, 5, 7, 8, 10 and 12 have 31 days.
+ *  Month 2 has 28 days, or 29 in a leap year.
+ * <li>day-of-year - There are 365 days in a standard ISO year and 366 in a leap year.
+ *  The days are numbered from 1 to 365 or 1 to 366.
+ * <li>leap-year - Leap years occur every 4 years, except where the year is divisble by 100 and not divisble by 400.
+ * </ul><p>
+ *
+ * <h3>Specification for implementors</h3>
+ * This class is immutable and thread-safe.
+ *
+ * @since 1.8
+ */
+public final class ISOChrono extends Chrono<ISOChrono> implements Serializable {
+
+    /**
+     * Singleton instance of the ISO chronology.
+     */
+    public static final ISOChrono INSTANCE = new ISOChrono();
+    /**
+     * The singleton instance for the era BCE - 'Before Current Era'.
+     * The 'ISO' part of the name emphasizes that this differs from the BCE
+     * era in the Gregorian calendar system.
+     * This has the numeric value of {@code 0}.
+     */
+    public static final Era<ISOChrono> ERA_BCE = ISOEra.BCE;
+    /**
+     * The singleton instance for the era CE - 'Current Era'.
+     * The 'ISO' part of the name emphasizes that this differs from the CE
+     * era in the Gregorian calendar system.
+     * This has the numeric value of {@code 1}.
+     */
+    public static final Era<ISOChrono> ERA_CE = ISOEra.CE;
+
+    /**
+     * Serialization version.
+     */
+    private static final long serialVersionUID = -1440403870442975015L;
+
+    /**
+     * Restricted constructor.
+     */
+    private ISOChrono() {
+    }
+
+    /**
+     * Resolve singleton.
+     *
+     * @return the singleton instance, not null
+     */
+    private Object readResolve() {
+        return INSTANCE;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the ID of the chronology - 'ISO'.
+     * <p>
+     * The ID uniquely identifies the {@code Chrono}.
+     * It can be used to lookup the {@code Chrono} using {@link #of(String)}.
+     *
+     * @return the chronology ID - 'ISO'
+     * @see #getCalendarType()
+     */
+    @Override
+    public String getId() {
+        return "ISO";
+    }
+
+    /**
+     * Gets the calendar type of the underlying calendar system - 'iso8601'.
+     * <p>
+     * The calendar type is an identifier defined by the
+     * <em>Unicode Locale Data Markup Language (LDML)</em> specification.
+     * It can be used to lookup the {@code Chrono} using {@link #of(String)}.
+     * It can also be used as part of a locale, accessible via
+     * {@link Locale#getUnicodeLocaleType(String)} with the key 'ca'.
+     *
+     * @return the calendar system type - 'iso8601'
+     * @see #getId()
+     */
+    @Override
+    public String getCalendarType() {
+        return "iso8601";
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an ISO local date from the era, year-of-era, month-of-year
+     * and day-of-month fields.
+     *
+     * @param era  the ISO era, not null
+     * @param yearOfEra  the ISO year-of-era
+     * @param month  the ISO month-of-year
+     * @param dayOfMonth  the ISO day-of-month
+     * @return the ISO local date, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate date(Era<ISOChrono> era, int yearOfEra, int month, int dayOfMonth) {
+        return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
+    }
+
+    /**
+     * Obtains an ISO local date from the proleptic-year, month-of-year
+     * and day-of-month fields.
+     * <p>
+     * This is equivalent to {@link LocalDate#of(int, int, int)}.
+     *
+     * @param prolepticYear  the ISO proleptic-year
+     * @param month  the ISO month-of-year
+     * @param dayOfMonth  the ISO day-of-month
+     * @return the ISO local date, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate date(int prolepticYear, int month, int dayOfMonth) {
+        return LocalDate.of(prolepticYear, month, dayOfMonth);
+    }
+
+    /**
+     * Obtains an ISO local date from the era, year-of-era and day-of-year fields.
+     *
+     * @param era  the ISO era, not null
+     * @param yearOfEra  the ISO year-of-era
+     * @param dayOfYear  the ISO day-of-year
+     * @return the ISO local date, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate dateYearDay(Era<ISOChrono> era, int yearOfEra, int dayOfYear) {
+        return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
+    }
+
+    /**
+     * Obtains an ISO local date from the proleptic-year and day-of-year fields.
+     * <p>
+     * This is equivalent to {@link LocalDate#ofYearDay(int, int)}.
+     *
+     * @param prolepticYear  the ISO proleptic-year
+     * @param dayOfYear  the ISO day-of-year
+     * @return the ISO local date, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate dateYearDay(int prolepticYear, int dayOfYear) {
+        return LocalDate.ofYearDay(prolepticYear, dayOfYear);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an ISO local date from another date-time object.
+     * <p>
+     * This is equivalent to {@link LocalDate#from(TemporalAccessor)}.
+     *
+     * @param temporal  the date-time object to convert, not null
+     * @return the ISO local date, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate date(TemporalAccessor temporal) {
+        return LocalDate.from(temporal);
+    }
+
+    /**
+     * Obtains an ISO local date-time from another date-time object.
+     * <p>
+     * This is equivalent to {@link LocalDateTime#from(TemporalAccessor)}.
+     *
+     * @param temporal  the date-time object to convert, not null
+     * @return the ISO local date-time, not null
+     * @throws DateTimeException if unable to create the date-time
+     */
+    @Override  // override with covariant return type
+    public LocalDateTime localDateTime(TemporalAccessor temporal) {
+        return LocalDateTime.from(temporal);
+    }
+
+    /**
+     * Obtains an ISO zoned date-time from another date-time object.
+     * <p>
+     * This is equivalent to {@link ZonedDateTime#from(TemporalAccessor)}.
+     *
+     * @param temporal  the date-time object to convert, not null
+     * @return the ISO zoned date-time, not null
+     * @throws DateTimeException if unable to create the date-time
+     */
+    @Override  // override with covariant return type
+    public ZonedDateTime zonedDateTime(TemporalAccessor temporal) {
+        return ZonedDateTime.from(temporal);
+    }
+
+    /**
+     * Obtains an ISO zoned date-time in this chronology from an {@code Instant}.
+     * <p>
+     * This is equivalent to {@link ZonedDateTime#ofInstant(Instant, ZoneId)}.
+     *
+     * @param instant  the instant to create the date-time from, not null
+     * @param zone  the time-zone, not null
+     * @return the zoned date-time, not null
+     * @throws DateTimeException if the result exceeds the supported range
+     */
+    public ZonedDateTime zonedDateTime(Instant instant, ZoneId zone) {
+        return ZonedDateTime.ofInstant(instant, zone);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains the current ISO local date from the system clock in the default time-zone.
+     * <p>
+     * This will query the {@link Clock#systemDefaultZone() system clock} in the default
+     * time-zone to obtain the current date.
+     * <p>
+     * Using this method will prevent the ability to use an alternate clock for testing
+     * because the clock is hard-coded.
+     *
+     * @return the current ISO local date using the system clock and default time-zone, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate dateNow() {
+        return dateNow(Clock.systemDefaultZone());
+    }
+
+    /**
+     * Obtains the current ISO local date from the system clock in the specified time-zone.
+     * <p>
+     * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
+     * Specifying the time-zone avoids dependence on the default time-zone.
+     * <p>
+     * Using this method will prevent the ability to use an alternate clock for testing
+     * because the clock is hard-coded.
+     *
+     * @return the current ISO local date using the system clock, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate dateNow(ZoneId zone) {
+        return dateNow(Clock.system(zone));
+    }
+
+    /**
+     * Obtains the current ISO local date from the specified clock.
+     * <p>
+     * This will query the specified clock to obtain the current date - today.
+     * Using this method allows the use of an alternate clock for testing.
+     * The alternate clock may be introduced using {@link Clock dependency injection}.
+     *
+     * @param clock  the clock to use, not null
+     * @return the current ISO local date, not null
+     * @throws DateTimeException if unable to create the date
+     */
+    @Override  // override with covariant return type
+    public LocalDate dateNow(Clock clock) {
+        Objects.requireNonNull(clock, "clock");
+        return date(LocalDate.now(clock));
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if the year is a leap year, according to the ISO proleptic
+     * calendar system rules.
+     * <p>
+     * This method applies the current rules for leap years across the whole time-line.
+     * In general, a year is a leap year if it is divisible by four without
+     * remainder. However, years divisible by 100, are not leap years, with
+     * the exception of years divisible by 400 which are.
+     * <p>
+     * For example, 1904 is a leap year it is divisible by 4.
+     * 1900 was not a leap year as it is divisible by 100, however 2000 was a
+     * leap year as it is divisible by 400.
+     * <p>
+     * The calculation is proleptic - applying the same rules into the far future and far past.
+     * This is historically inaccurate, but is correct for the ISO-8601 standard.
+     *
+     * @param prolepticYear  the ISO proleptic year to check
+     * @return true if the year is leap, false otherwise
+     */
+    @Override
+    public boolean isLeapYear(long prolepticYear) {
+        return ((prolepticYear & 3) == 0) && ((prolepticYear % 100) != 0 || (prolepticYear % 400) == 0);
+    }
+
+    @Override
+    public int prolepticYear(Era<ISOChrono> era, int yearOfEra) {
+        if (era instanceof ISOEra == false) {
+            throw new DateTimeException("Era must be ISOEra");
+        }
+        return (era == ISOEra.CE ? yearOfEra : 1 - yearOfEra);
+    }
+
+    @Override
+    public Era<ISOChrono> eraOf(int eraValue) {
+        return ISOEra.of(eraValue);
+    }
+
+    @Override
+    public List<Era<ISOChrono>> eras() {
+        return Arrays.<Era<ISOChrono>>asList(ISOEra.values());
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public ValueRange range(ChronoField field) {
+        return field.range();
+    }
+
+}