jdk/src/share/classes/java/time/temporal/ISOFields.java
changeset 15658 55b829ca2334
parent 15657 c588664d547e
child 15659 e575dab44ff5
equal deleted inserted replaced
15657:c588664d547e 15658:55b829ca2334
     1 /*
       
     2  * Copyright (c) 2012, 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 /*
       
    27  * Copyright (c) 2011-2012, Stephen Colebourne & Michael Nascimento Santos
       
    28  *
       
    29  * All rights reserved.
       
    30  *
       
    31  * Redistribution and use in source and binary forms, with or without
       
    32  * modification, are permitted provided that the following conditions are met:
       
    33  *
       
    34  *  * Redistributions of source code must retain the above copyright notice,
       
    35  *    this list of conditions and the following disclaimer.
       
    36  *
       
    37  *  * Redistributions in binary form must reproduce the above copyright notice,
       
    38  *    this list of conditions and the following disclaimer in the documentation
       
    39  *    and/or other materials provided with the distribution.
       
    40  *
       
    41  *  * Neither the name of JSR-310 nor the names of its contributors
       
    42  *    may be used to endorse or promote products derived from this software
       
    43  *    without specific prior written permission.
       
    44  *
       
    45  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
       
    46  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
       
    47  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
       
    48  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
       
    49  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
       
    50  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
       
    51  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
       
    52  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
       
    53  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
       
    54  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
       
    55  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
       
    56  */
       
    57 package java.time.temporal;
       
    58 
       
    59 import static java.time.DayOfWeek.THURSDAY;
       
    60 import static java.time.DayOfWeek.WEDNESDAY;
       
    61 import static java.time.temporal.ChronoField.DAY_OF_WEEK;
       
    62 import static java.time.temporal.ChronoField.DAY_OF_YEAR;
       
    63 import static java.time.temporal.ChronoField.EPOCH_DAY;
       
    64 import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
       
    65 import static java.time.temporal.ChronoField.YEAR;
       
    66 import static java.time.temporal.ChronoUnit.DAYS;
       
    67 import static java.time.temporal.ChronoUnit.FOREVER;
       
    68 import static java.time.temporal.ChronoUnit.MONTHS;
       
    69 import static java.time.temporal.ChronoUnit.WEEKS;
       
    70 import static java.time.temporal.ChronoUnit.YEARS;
       
    71 
       
    72 import java.time.DateTimeException;
       
    73 import java.time.Duration;
       
    74 import java.time.LocalDate;
       
    75 import java.time.format.DateTimeBuilder;
       
    76 
       
    77 /**
       
    78  * Fields and units specific to the ISO-8601 calendar system,
       
    79  * including quarter-of-year and week-based-year.
       
    80  * <p>
       
    81  * This class defines fields and units that are specific to the ISO calendar system.
       
    82  *
       
    83  * <h3>Quarter of year</h3>
       
    84  * The ISO-8601 standard is based on the standard civic 12 month year.
       
    85  * This is commonly divided into four quarters, often abbreviated as Q1, Q2, Q3 and Q4.
       
    86  * <p>
       
    87  * January, February and March are in Q1.
       
    88  * April, May and June are in Q2.
       
    89  * July, August and September are in Q3.
       
    90  * October, November and December are in Q4.
       
    91  * <p>
       
    92  * The complete date is expressed using three fields:
       
    93  * <p><ul>
       
    94  * <li>{@link #DAY_OF_QUARTER DAY_OF_QUARTER} - the day within the quarter, from 1 to 90, 91 or 92
       
    95  * <li>{@link #QUARTER_OF_YEAR QUARTER_OF_YEAR} - the week within the week-based-year
       
    96  * <li>{@link ChronoField#YEAR YEAR} - the standard ISO year
       
    97  * </ul><p>
       
    98  *
       
    99  * <h3>Week based years</h3>
       
   100  * The ISO-8601 standard was originally intended as a data interchange format,
       
   101  * defining a string format for dates and times. However, it also defines an
       
   102  * alternate way of expressing the date, based on the concept of week-based-year.
       
   103  * <p>
       
   104  * The date is expressed using three fields:
       
   105  * <p><ul>
       
   106  * <li>{@link ChronoField#DAY_OF_WEEK DAY_OF_WEEK} - the standard field defining the
       
   107  *  day-of-week from Monday (1) to Sunday (7)
       
   108  * <li>{@link #WEEK_OF_WEEK_BASED_YEAR} - the week within the week-based-year
       
   109  * <li>{@link #WEEK_BASED_YEAR WEEK_BASED_YEAR} - the week-based-year
       
   110  * </ul><p>
       
   111  * The week-based-year itself is defined relative to the standard ISO proleptic year.
       
   112  * It differs from the standard year in that it always starts on a Monday.
       
   113  * <p>
       
   114  * The first week of a week-based-year is the first Monday-based week of the standard
       
   115  * ISO year that has at least 4 days in the new year.
       
   116  * <p><ul>
       
   117  * <li>If January 1st is Monday then week 1 starts on January 1st
       
   118  * <li>If January 1st is Tuesday then week 1 starts on December 31st of the previous standard year
       
   119  * <li>If January 1st is Wednesday then week 1 starts on December 30th of the previous standard year
       
   120  * <li>If January 1st is Thursday then week 1 starts on December 29th of the previous standard year
       
   121  * <li>If January 1st is Friday then week 1 starts on January 4th
       
   122  * <li>If January 1st is Saturday then week 1 starts on January 3rd
       
   123  * <li>If January 1st is Sunday then week 1 starts on January 2nd
       
   124  * </ul><p>
       
   125  * There are 52 weeks in most week-based years, however on occasion there are 53 weeks.
       
   126  * <p>
       
   127  * For example:
       
   128  * <p>
       
   129  * <table cellpadding="0" cellspacing="3" border="0" style="text-align: left; width: 50%;">
       
   130  * <caption>Examples of Week based Years</caption>
       
   131  * <tr><th>Date</th><th>Day-of-week</th><th>Field values</th></tr>
       
   132  * <tr><th>2008-12-28</th><td>Sunday</td><td>Week 52 of week-based-year 2008</td></tr>
       
   133  * <tr><th>2008-12-29</th><td>Monday</td><td>Week 1 of week-based-year 2009</td></tr>
       
   134  * <tr><th>2008-12-31</th><td>Wednesday</td><td>Week 1 of week-based-year 2009</td></tr>
       
   135  * <tr><th>2009-01-01</th><td>Thursday</td><td>Week 1 of week-based-year 2009</td></tr>
       
   136  * <tr><th>2009-01-04</th><td>Sunday</td><td>Week 1 of week-based-year 2009</td></tr>
       
   137  * <tr><th>2009-01-05</th><td>Monday</td><td>Week 2 of week-based-year 2009</td></tr>
       
   138  * </table>
       
   139  *
       
   140  * <h3>Specification for implementors</h3>
       
   141  * <p>
       
   142  * This class is immutable and thread-safe.
       
   143  *
       
   144  * @since 1.8
       
   145  */
       
   146 public final class ISOFields {
       
   147 
       
   148     /**
       
   149      * The field that represents the day-of-quarter.
       
   150      * <p>
       
   151      * This field allows the day-of-quarter value to be queried and set.
       
   152      * The day-of-quarter has values from 1 to 90 in Q1 of a standard year, from 1 to 91
       
   153      * in Q1 of a leap year, from 1 to 91 in Q2 and from 1 to 92 in Q3 and Q4.
       
   154      * <p>
       
   155      * The day-of-quarter can only be calculated if the day-of-year, month-of-year and year
       
   156      * are available.
       
   157      * <p>
       
   158      * When setting this field, the value is allowed to be partially lenient, taking any
       
   159      * value from 1 to 92. If the quarter has less than 92 days, then day 92, and
       
   160      * potentially day 91, is in the following quarter.
       
   161      * <p>
       
   162      * This unit is an immutable and thread-safe singleton.
       
   163      */
       
   164     public static final TemporalField DAY_OF_QUARTER = Field.DAY_OF_QUARTER;
       
   165     /**
       
   166      * The field that represents the quarter-of-year.
       
   167      * <p>
       
   168      * This field allows the quarter-of-year value to be queried and set.
       
   169      * The quarter-of-year has values from 1 to 4.
       
   170      * <p>
       
   171      * The day-of-quarter can only be calculated if the month-of-year is available.
       
   172      * <p>
       
   173      * This unit is an immutable and thread-safe singleton.
       
   174      */
       
   175     public static final TemporalField QUARTER_OF_YEAR = Field.QUARTER_OF_YEAR;
       
   176     /**
       
   177      * The field that represents the week-of-week-based-year.
       
   178      * <p>
       
   179      * This field allows the week of the week-based-year value to be queried and set.
       
   180      * <p>
       
   181      * This unit is an immutable and thread-safe singleton.
       
   182      */
       
   183     public static final TemporalField WEEK_OF_WEEK_BASED_YEAR = Field.WEEK_OF_WEEK_BASED_YEAR;
       
   184     /**
       
   185      * The field that represents the week-based-year.
       
   186      * <p>
       
   187      * This field allows the week-based-year value to be queried and set.
       
   188      * <p>
       
   189      * This unit is an immutable and thread-safe singleton.
       
   190      */
       
   191     public static final TemporalField WEEK_BASED_YEAR = Field.WEEK_BASED_YEAR;
       
   192     /**
       
   193      * The unit that represents week-based-years for the purpose of addition and subtraction.
       
   194      * <p>
       
   195      * This allows a number of week-based-years to be added to, or subtracted from, a date.
       
   196      * The unit is equal to either 52 or 53 weeks.
       
   197      * The estimated duration of a week-based-year is the same as that of a standard ISO
       
   198      * year at {@code 365.2425 Days}.
       
   199      * <p>
       
   200      * The rules for addition add the number of week-based-years to the existing value
       
   201      * for the week-based-year field. If the resulting week-based-year only has 52 weeks,
       
   202      * then the date will be in week 1 of the following week-based-year.
       
   203      * <p>
       
   204      * This unit is an immutable and thread-safe singleton.
       
   205      */
       
   206     public static final TemporalUnit WEEK_BASED_YEARS = Unit.WEEK_BASED_YEARS;
       
   207     /**
       
   208      * Unit that represents the concept of a quarter-year.
       
   209      * For the ISO calendar system, it is equal to 3 months.
       
   210      * The estimated duration of a quarter-year is one quarter of {@code 365.2425 Days}.
       
   211      * <p>
       
   212      * This unit is an immutable and thread-safe singleton.
       
   213      */
       
   214     public static final TemporalUnit QUARTER_YEARS = Unit.QUARTER_YEARS;
       
   215 
       
   216     /**
       
   217      * Restricted constructor.
       
   218      */
       
   219     private ISOFields() {
       
   220         throw new AssertionError("Not instantiable");
       
   221     }
       
   222 
       
   223     //-----------------------------------------------------------------------
       
   224     /**
       
   225      * Implementation of the field.
       
   226      */
       
   227     private static enum Field implements TemporalField {
       
   228         DAY_OF_QUARTER {
       
   229             @Override
       
   230             public String getName() {
       
   231                 return "DayOfQuarter";
       
   232             }
       
   233             @Override
       
   234             public TemporalUnit getBaseUnit() {
       
   235                 return DAYS;
       
   236             }
       
   237             @Override
       
   238             public TemporalUnit getRangeUnit() {
       
   239                 return QUARTER_YEARS;
       
   240             }
       
   241             @Override
       
   242             public ValueRange range() {
       
   243                 return ValueRange.of(1, 90, 92);
       
   244             }
       
   245             @Override
       
   246             public boolean doIsSupported(TemporalAccessor temporal) {
       
   247                 return temporal.isSupported(DAY_OF_YEAR) && temporal.isSupported(MONTH_OF_YEAR) &&
       
   248                         temporal.isSupported(YEAR) && Chrono.from(temporal).equals(ISOChrono.INSTANCE);
       
   249             }
       
   250             @Override
       
   251             public ValueRange doRange(TemporalAccessor temporal) {
       
   252                 if (doIsSupported(temporal) == false) {
       
   253                     throw new DateTimeException("Unsupported field: DayOfQuarter");
       
   254                 }
       
   255                 long qoy = temporal.getLong(QUARTER_OF_YEAR);
       
   256                 if (qoy == 1) {
       
   257                     long year = temporal.getLong(YEAR);
       
   258                     return (ISOChrono.INSTANCE.isLeapYear(year) ? ValueRange.of(1, 91) : ValueRange.of(1, 90));
       
   259                 } else if (qoy == 2) {
       
   260                     return ValueRange.of(1, 91);
       
   261                 } else if (qoy == 3 || qoy == 4) {
       
   262                     return ValueRange.of(1, 92);
       
   263                 } // else value not from 1 to 4, so drop through
       
   264                 return range();
       
   265             }
       
   266             @Override
       
   267             public long doGet(TemporalAccessor temporal) {
       
   268                 if (doIsSupported(temporal) == false) {
       
   269                     throw new DateTimeException("Unsupported field: DayOfQuarter");
       
   270                 }
       
   271                 int doy = temporal.get(DAY_OF_YEAR);
       
   272                 int moy = temporal.get(MONTH_OF_YEAR);
       
   273                 long year = temporal.getLong(YEAR);
       
   274                 return doy - QUARTER_DAYS[((moy - 1) / 3) + (ISOChrono.INSTANCE.isLeapYear(year) ? 4 : 0)];
       
   275             }
       
   276             @Override
       
   277             public <R extends Temporal> R doWith(R temporal, long newValue) {
       
   278                 long curValue = doGet(temporal);
       
   279                 range().checkValidValue(newValue, this);
       
   280                 return (R) temporal.with(DAY_OF_YEAR, temporal.getLong(DAY_OF_YEAR) + (newValue - curValue));
       
   281             }
       
   282         },
       
   283         QUARTER_OF_YEAR {
       
   284             @Override
       
   285             public String getName() {
       
   286                 return "QuarterOfYear";
       
   287             }
       
   288             @Override
       
   289             public TemporalUnit getBaseUnit() {
       
   290                 return QUARTER_YEARS;
       
   291             }
       
   292             @Override
       
   293             public TemporalUnit getRangeUnit() {
       
   294                 return YEARS;
       
   295             }
       
   296             @Override
       
   297             public ValueRange range() {
       
   298                 return ValueRange.of(1, 4);
       
   299             }
       
   300             @Override
       
   301             public boolean doIsSupported(TemporalAccessor temporal) {
       
   302                 return temporal.isSupported(MONTH_OF_YEAR) && Chrono.from(temporal).equals(ISOChrono.INSTANCE);
       
   303             }
       
   304             @Override
       
   305             public long doGet(TemporalAccessor temporal) {
       
   306                 if (doIsSupported(temporal) == false) {
       
   307                     throw new DateTimeException("Unsupported field: DayOfQuarter");
       
   308                 }
       
   309                 long moy = temporal.getLong(MONTH_OF_YEAR);
       
   310                 return ((moy + 2) / 3);
       
   311             }
       
   312             @Override
       
   313             public <R extends Temporal> R doWith(R temporal, long newValue) {
       
   314                 long curValue = doGet(temporal);
       
   315                 range().checkValidValue(newValue, this);
       
   316                 return (R) temporal.with(MONTH_OF_YEAR, temporal.getLong(MONTH_OF_YEAR) + (newValue - curValue) * 3);
       
   317             }
       
   318             @Override
       
   319             public boolean resolve(DateTimeBuilder builder, long value) {
       
   320                 Long[] values = builder.queryFieldValues(YEAR, QUARTER_OF_YEAR, DAY_OF_QUARTER);
       
   321                 if (values[0] != null && values[1] != null && values[2] != null) {
       
   322                     int y = YEAR.range().checkValidIntValue(values[0], YEAR);
       
   323                     int qoy = QUARTER_OF_YEAR.range().checkValidIntValue(values[1], QUARTER_OF_YEAR);
       
   324                     int doq = DAY_OF_QUARTER.range().checkValidIntValue(values[2], DAY_OF_QUARTER);
       
   325                     LocalDate date = LocalDate.of(y, ((qoy - 1) * 3) + 1, 1).plusDays(doq - 1);
       
   326                     builder.addFieldValue(EPOCH_DAY, date.toEpochDay());
       
   327                     builder.removeFieldValues(QUARTER_OF_YEAR, DAY_OF_QUARTER);
       
   328                 }
       
   329                 return false;
       
   330             }
       
   331         },
       
   332         WEEK_OF_WEEK_BASED_YEAR {
       
   333             @Override
       
   334             public String getName() {
       
   335                 return "WeekOfWeekBasedYear";
       
   336             }
       
   337             @Override
       
   338             public TemporalUnit getBaseUnit() {
       
   339                 return WEEKS;
       
   340             }
       
   341             @Override
       
   342             public TemporalUnit getRangeUnit() {
       
   343                 return WEEK_BASED_YEARS;
       
   344             }
       
   345             @Override
       
   346             public ValueRange range() {
       
   347                 return ValueRange.of(1, 52, 53);
       
   348             }
       
   349             @Override
       
   350             public boolean doIsSupported(TemporalAccessor temporal) {
       
   351                 return temporal.isSupported(EPOCH_DAY);
       
   352             }
       
   353             @Override
       
   354             public ValueRange doRange(TemporalAccessor temporal) {
       
   355                 return getWeekRange(LocalDate.from(temporal));
       
   356             }
       
   357             @Override
       
   358             public long doGet(TemporalAccessor temporal) {
       
   359                 return getWeek(LocalDate.from(temporal));
       
   360             }
       
   361             @Override
       
   362             public <R extends Temporal> R doWith(R temporal, long newValue) {
       
   363                 ValueRange.of(1, 53).checkValidValue(newValue, this);
       
   364                 return (R) temporal.plus(Math.subtractExact(newValue, doGet(temporal)), WEEKS);
       
   365             }
       
   366         },
       
   367         WEEK_BASED_YEAR {
       
   368             @Override
       
   369             public String getName() {
       
   370                 return "WeekBasedYear";
       
   371             }
       
   372             @Override
       
   373             public TemporalUnit getBaseUnit() {
       
   374                 return WEEK_BASED_YEARS;
       
   375             }
       
   376             @Override
       
   377             public TemporalUnit getRangeUnit() {
       
   378                 return FOREVER;
       
   379             }
       
   380             @Override
       
   381             public ValueRange range() {
       
   382                 return YEAR.range();
       
   383             }
       
   384             @Override
       
   385             public boolean doIsSupported(TemporalAccessor temporal) {
       
   386                 return temporal.isSupported(EPOCH_DAY);
       
   387             }
       
   388             @Override
       
   389             public long doGet(TemporalAccessor temporal) {
       
   390                 return getWeekBasedYear(LocalDate.from(temporal));
       
   391             }
       
   392             @Override
       
   393             public <R extends Temporal> R doWith(R temporal, long newValue) {
       
   394                 int newVal = range().checkValidIntValue(newValue, WEEK_BASED_YEAR);
       
   395                 LocalDate date = LocalDate.from(temporal);
       
   396                 int week = getWeek(date);
       
   397                 date = date.withDayOfYear(180).withYear(newVal).with(WEEK_OF_WEEK_BASED_YEAR, week);
       
   398                 return (R) date.with(date);
       
   399             }
       
   400             @Override
       
   401             public boolean resolve(DateTimeBuilder builder, long value) {
       
   402                 Long[] values = builder.queryFieldValues(WEEK_BASED_YEAR, WEEK_OF_WEEK_BASED_YEAR, DAY_OF_WEEK);
       
   403                 if (values[0] != null && values[1] != null && values[2] != null) {
       
   404                     int wby = WEEK_BASED_YEAR.range().checkValidIntValue(values[0], WEEK_BASED_YEAR);
       
   405                     int week = WEEK_OF_WEEK_BASED_YEAR.range().checkValidIntValue(values[1], WEEK_OF_WEEK_BASED_YEAR);
       
   406                     int dow = DAY_OF_WEEK.range().checkValidIntValue(values[2], DAY_OF_WEEK);
       
   407                     LocalDate date = LocalDate.of(wby, 2, 1).with(WEEK_OF_WEEK_BASED_YEAR, week).with(DAY_OF_WEEK, dow);
       
   408                     builder.addFieldValue(EPOCH_DAY, date.toEpochDay());
       
   409                     builder.removeFieldValues(WEEK_BASED_YEAR, WEEK_OF_WEEK_BASED_YEAR, DAY_OF_WEEK);
       
   410                 }
       
   411                 return false;
       
   412             }
       
   413         };
       
   414 
       
   415         @Override
       
   416         public ValueRange doRange(TemporalAccessor temporal) {
       
   417             return range();
       
   418         }
       
   419 
       
   420         @Override
       
   421         public boolean resolve(DateTimeBuilder builder, long value) {
       
   422             return false;
       
   423         }
       
   424 
       
   425         @Override
       
   426         public String toString() {
       
   427             return getName();
       
   428         }
       
   429 
       
   430         //-------------------------------------------------------------------------
       
   431         private static final int[] QUARTER_DAYS = {0, 90, 181, 273, 0, 91, 182, 274};
       
   432 
       
   433         private static ValueRange getWeekRange(LocalDate date) {
       
   434             int wby = getWeekBasedYear(date);
       
   435             date = date.withDayOfYear(1).withYear(wby);
       
   436             // 53 weeks if standard year starts on Thursday, or Wed in a leap year
       
   437             if (date.getDayOfWeek() == THURSDAY || (date.getDayOfWeek() == WEDNESDAY && date.isLeapYear())) {
       
   438                 return ValueRange.of(1, 53);
       
   439             }
       
   440             return ValueRange.of(1, 52);
       
   441         }
       
   442 
       
   443         private static int getWeek(LocalDate date) {
       
   444             int dow0 = date.getDayOfWeek().ordinal();
       
   445             int doy0 = date.getDayOfYear() - 1;
       
   446             int doyThu0 = doy0 + (3 - dow0);  // adjust to mid-week Thursday (which is 3 indexed from zero)
       
   447             int alignedWeek = doyThu0 / 7;
       
   448             int firstThuDoy0 = doyThu0 - (alignedWeek * 7);
       
   449             int firstMonDoy0 = firstThuDoy0 - 3;
       
   450             if (firstMonDoy0 < -3) {
       
   451                 firstMonDoy0 += 7;
       
   452             }
       
   453             if (doy0 < firstMonDoy0) {
       
   454                 return (int) getWeekRange(date.withDayOfYear(180).minusYears(1)).getMaximum();
       
   455             }
       
   456             int week = ((doy0 - firstMonDoy0) / 7) + 1;
       
   457             if (week == 53) {
       
   458                 if ((firstMonDoy0 == -3 || (firstMonDoy0 == -2 && date.isLeapYear())) == false) {
       
   459                     week = 1;
       
   460                 }
       
   461             }
       
   462             return week;
       
   463         }
       
   464 
       
   465         private static int getWeekBasedYear(LocalDate date) {
       
   466             int year = date.getYear();
       
   467             int doy = date.getDayOfYear();
       
   468             if (doy <= 3) {
       
   469                 int dow = date.getDayOfWeek().ordinal();
       
   470                 if (doy - dow < -2) {
       
   471                     year--;
       
   472                 }
       
   473             } else if (doy >= 363) {
       
   474                 int dow = date.getDayOfWeek().ordinal();
       
   475                 doy = doy - 363 - (date.isLeapYear() ? 1 : 0);
       
   476                 if (doy - dow >= 0) {
       
   477                     year++;
       
   478                 }
       
   479             }
       
   480             return year;
       
   481         }
       
   482     }
       
   483 
       
   484     //-----------------------------------------------------------------------
       
   485     /**
       
   486      * Implementation of the period unit.
       
   487      */
       
   488     private static enum Unit implements TemporalUnit {
       
   489 
       
   490         /**
       
   491          * Unit that represents the concept of a week-based-year.
       
   492          */
       
   493         WEEK_BASED_YEARS("WeekBasedYears", Duration.ofSeconds(31556952L)),
       
   494         /**
       
   495          * Unit that represents the concept of a quarter-year.
       
   496          */
       
   497         QUARTER_YEARS("QuarterYears", Duration.ofSeconds(31556952L / 4));
       
   498 
       
   499         private final String name;
       
   500         private final Duration duration;
       
   501 
       
   502         private Unit(String name, Duration estimatedDuration) {
       
   503             this.name = name;
       
   504             this.duration = estimatedDuration;
       
   505         }
       
   506 
       
   507         @Override
       
   508         public String getName() {
       
   509             return name;
       
   510         }
       
   511 
       
   512         @Override
       
   513         public Duration getDuration() {
       
   514             return duration;
       
   515         }
       
   516 
       
   517         @Override
       
   518         public boolean isDurationEstimated() {
       
   519             return true;
       
   520         }
       
   521 
       
   522         @Override
       
   523         public boolean isSupported(Temporal temporal) {
       
   524             return temporal.isSupported(EPOCH_DAY);
       
   525         }
       
   526 
       
   527         @Override
       
   528         public <R extends Temporal> R doPlus(R dateTime, long periodToAdd) {
       
   529             switch(this) {
       
   530                 case WEEK_BASED_YEARS:
       
   531                     return (R) dateTime.with(WEEK_BASED_YEAR,
       
   532                             Math.addExact(dateTime.get(WEEK_BASED_YEAR), periodToAdd));
       
   533                 case QUARTER_YEARS:
       
   534                     // no overflow (256 is multiple of 4)
       
   535                     return (R) dateTime.plus(periodToAdd / 256, YEARS)
       
   536                             .plus((periodToAdd % 256) * 3, MONTHS);
       
   537                 default:
       
   538                     throw new IllegalStateException("Unreachable");
       
   539             }
       
   540         }
       
   541 
       
   542         @Override
       
   543         public <R extends Temporal> SimplePeriod between(R dateTime1, R dateTime2) {
       
   544             switch(this) {
       
   545                 case WEEK_BASED_YEARS:
       
   546                     long period = Math.subtractExact(dateTime2.getLong(WEEK_BASED_YEAR),
       
   547                             dateTime1.getLong(WEEK_BASED_YEAR));
       
   548                     return new SimplePeriod(period, WEEK_BASED_YEARS);
       
   549                 case QUARTER_YEARS:
       
   550                     long period2 = Math.subtractExact(dateTime2.getLong(QUARTER_OF_YEAR),
       
   551                             dateTime1.getLong(QUARTER_OF_YEAR));
       
   552                     return new SimplePeriod(period2, QUARTER_YEARS);
       
   553                 default:
       
   554                     throw new IllegalStateException("Unreachable");
       
   555             }
       
   556         }
       
   557 
       
   558         @Override
       
   559         public String toString() {
       
   560             return getName();
       
   561 
       
   562         }
       
   563     }
       
   564 }