4267450: (cal) API: Need public API to calculate, format and parse "year of week"

6549953: (cal) WEEK_OF_YEAR and DAY_OF_YEAR calculation problems around Gregorian cutover
Reviewed-by: peytoia

make/java/text/base/FILES_java.gmk

 #
-# Copyright (c) 1996, 2007, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 1996, 2010, 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
@@ -29,6 +29,7 @@ FILES_java = \
     java/text/AttributedString.java \
     java/text/BreakDictionary.java \
     java/text/BreakIterator.java \
+    java/text/CalendarBuilder.java \
     java/text/CharacterIterator.java \
     java/text/CharacterIteratorFieldDelegate.java \
     java/text/ChoiceFormat.java \

src/share/classes/java/text/CalendarBuilder.java

+/*
+ * Copyright (c) 2010, 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.
+ */
+
+package java.text;
+
+import java.util.Calendar;
+import static java.util.GregorianCalendar.*;
+
+/**
+ * {@code CalendarBuilder} keeps field-value pairs for setting
+ * the calendar fields of the given {@code Calendar}. It has the
+ * {@link Calendar#FIELD_COUNT FIELD_COUNT}-th field for the week year
+ * support. Also {@code ISO_DAY_OF_WEEK} is used to specify
+ * {@code DAY_OF_WEEK} in the ISO day of week numbering.
+ *
+ * <p>{@code CalendarBuilder} retains the semantic of the pseudo
+ * timestamp for fields. {@code CalendarBuilder} uses a single
+ * int array combining fields[] and stamp[] of {@code Calendar}.
+ *
+ * @author Masayoshi Okutsu
+ */
+class CalendarBuilder {
+    /*
+     * Pseudo time stamp constants used in java.util.Calendar
+     */
+    private static final int UNSET = 0;
+    private static final int COMPUTED = 1;
+    private static final int MINIMUM_USER_STAMP = 2;
+
+    private static final int MAX_FIELD = FIELD_COUNT + 1;
+
+    public static final int WEEK_YEAR = FIELD_COUNT;
+    public static final int ISO_DAY_OF_WEEK = 1000; // pseudo field index
+
+    // stamp[] (lower half) and field[] (upper half) combined
+    private final int[] field;
+    private int nextStamp;
+    private int maxFieldIndex;
+
+    CalendarBuilder() {
+        field = new int[MAX_FIELD * 2];
+        nextStamp = MINIMUM_USER_STAMP;
+        maxFieldIndex = -1;
+    }
+
+    CalendarBuilder set(int index, int value) {
+        if (index == ISO_DAY_OF_WEEK) {
+            index = DAY_OF_WEEK;
+            value = toCalendarDayOfWeek(value);
+        }
+        field[index] = nextStamp++;
+        field[MAX_FIELD + index] = value;
+        if (index > maxFieldIndex && index < FIELD_COUNT) {
+            maxFieldIndex = index;
+        }
+        return this;
+    }
+
+    CalendarBuilder addYear(int value) {
+        field[MAX_FIELD + YEAR] += value;
+        field[MAX_FIELD + WEEK_YEAR] += value;
+        return this;
+    }
+
+    boolean isSet(int index) {
+        if (index == ISO_DAY_OF_WEEK) {
+            index = DAY_OF_WEEK;
+        }
+        return field[index] > UNSET;
+    }
+
+    Calendar establish(Calendar cal) {
+        boolean weekDate = isSet(WEEK_YEAR)
+                            && field[WEEK_YEAR] > field[YEAR];
+        if (weekDate && !cal.isWeekDateSupported()) {
+            // Use YEAR instead
+            if (!isSet(YEAR)) {
+                set(YEAR, field[MAX_FIELD + WEEK_YEAR]);
+            }
+            weekDate = false;
+        }
+
+        cal.clear();
+        // Set the fields from the min stamp to the max stamp so that
+        // the field resolution works in the Calendar.
+        for (int stamp = MINIMUM_USER_STAMP; stamp < nextStamp; stamp++) {
+            for (int index = 0; index <= maxFieldIndex; index++) {
+                if (field[index] == stamp) {
+                    cal.set(index, field[MAX_FIELD + index]);
+                    break;
+                }
+            }
+        }
+
+        if (weekDate) {
+            int weekOfYear = isSet(WEEK_OF_YEAR) ? field[MAX_FIELD + WEEK_OF_YEAR] : 1;
+            int dayOfWeek = isSet(DAY_OF_WEEK) ?
+                                field[MAX_FIELD + DAY_OF_WEEK] : cal.getFirstDayOfWeek();
+            if (!isValidDayOfWeek(dayOfWeek) && cal.isLenient()) {
+                if (dayOfWeek >= 8) {
+                    dayOfWeek--;
+                    weekOfYear += dayOfWeek / 7;
+                    dayOfWeek = (dayOfWeek % 7) + 1;
+                } else {
+                    while (dayOfWeek <= 0) {
+                        dayOfWeek += 7;
+                        weekOfYear--;
+                    }
+                }
+                dayOfWeek = toCalendarDayOfWeek(dayOfWeek);
+            }
+            cal.setWeekDate(field[MAX_FIELD + WEEK_YEAR], weekOfYear, dayOfWeek);
+        }
+        return cal;
+    }
+
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append("CalendarBuilder:[");
+        for (int i = 0; i < field.length; i++) {
+            if (isSet(i)) {
+                sb.append(i).append('=').append(field[MAX_FIELD + i]).append(',');
+            }
+        }
+        int lastIndex = sb.length() - 1;
+        if (sb.charAt(lastIndex) == ',') {
+            sb.setLength(lastIndex);
+        }
+        sb.append(']');
+        return sb.toString();
+    }
+
+    static int toISODayOfWeek(int calendarDayOfWeek) {
+        return calendarDayOfWeek == SUNDAY ? 7 : calendarDayOfWeek - 1;
+    }
+
+    static int toCalendarDayOfWeek(int isoDayOfWeek) {
+        if (!isValidDayOfWeek(isoDayOfWeek)) {
+            // adjust later for lenient mode
+            return isoDayOfWeek;
+        }
+        return isoDayOfWeek == 7 ? SUNDAY : isoDayOfWeek + 1;
+    }
+
+    static boolean isValidDayOfWeek(int dayOfWeek) {
+        return dayOfWeek > 0 && dayOfWeek <= 7;
+    }
+}

src/share/classes/java/text/DateFormatSymbols.java

 /*
- * Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2010, 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
@@ -226,7 +226,29 @@ public class DateFormatSymbols implements Serializable, Cloneable {
      * Unlocalized date-time pattern characters. For example: 'y', 'd', etc.
      * All locales use the same these unlocalized pattern characters.
      */
-    static final String  patternChars = "GyMdkHmsSEDFwWahKzZ";
+    static final String  patternChars = "GyMdkHmsSEDFwWahKzZYu";
+
+    static final int PATTERN_ERA                  =  0; // G
+    static final int PATTERN_YEAR                 =  1; // y
+    static final int PATTERN_MONTH                =  2; // M
+    static final int PATTERN_DAY_OF_MONTH         =  3; // d
+    static final int PATTERN_HOUR_OF_DAY1         =  4; // k
+    static final int PATTERN_HOUR_OF_DAY0         =  5; // H
+    static final int PATTERN_MINUTE               =  6; // m
+    static final int PATTERN_SECOND               =  7; // s
+    static final int PATTERN_MILLISECOND          =  8; // S
+    static final int PATTERN_DAY_OF_WEEK          =  9; // E
+    static final int PATTERN_DAY_OF_YEAR          = 10; // D
+    static final int PATTERN_DAY_OF_WEEK_IN_MONTH = 11; // F
+    static final int PATTERN_WEEK_OF_YEAR         = 12; // w
+    static final int PATTERN_WEEK_OF_MONTH        = 13; // W
+    static final int PATTERN_AM_PM                = 14; // a
+    static final int PATTERN_HOUR1                = 15; // h
+    static final int PATTERN_HOUR0                = 16; // K
+    static final int PATTERN_ZONE_NAME            = 17; // z
+    static final int PATTERN_ZONE_VALUE           = 18; // Z
+    static final int PATTERN_WEEK_YEAR            = 19; // Y
+    static final int PATTERN_ISO_DAY_OF_WEEK      = 20; // u
 
     /**
      * Localized date-time pattern characters. For example, a locale may
@@ -505,7 +527,7 @@ public class DateFormatSymbols implements Serializable, Cloneable {
      * @return the localized date-time pattern characters.
      */
     public String getLocalPatternChars() {
-        return new String(localPatternChars);
+        return localPatternChars;
     }
 
     /**
@@ -514,7 +536,8 @@ public class DateFormatSymbols implements Serializable, Cloneable {
      * pattern characters.
      */
     public void setLocalPatternChars(String newLocalPatternChars) {
-        localPatternChars = new String(newLocalPatternChars);
+        // Call toString() to throw an NPE in case the argument is null
+        localPatternChars = newLocalPatternChars.toString();
     }
 
     /**
@@ -699,7 +722,7 @@ public class DateFormatSymbols implements Serializable, Cloneable {
         } else {
             dst.zoneStrings = null;
         }
-        dst.localPatternChars = new String (src.localPatternChars);
+        dst.localPatternChars = src.localPatternChars;
     }
 
     /**

src/share/classes/java/util/Calendar.java

 /*
- * Copyright (c) 1996, 2007, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1996, 2010, 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
@@ -119,7 +119,7 @@ import sun.util.resources.LocaleData;
  * calculating its time or calendar field values if any out-of-range field
  * value has been set.
  *
- * <h4>First Week</h4>
+ * <h4><a name="first_week">First Week</a></h4>
  *
  * <code>Calendar</code> defines a locale-specific seven day week using two
  * parameters: the first day of the week and the minimal days in first week
@@ -2195,6 +2195,101 @@ public abstract class Calendar implements Serializable, Cloneable, Comparable<Ca
         return minimalDaysInFirstWeek;
     }
 
+    /**
+     * Returns whether this {@code Calendar} supports week dates.
+     *
+     * <p>The default implementation of this method returns {@code false}.
+     *
+     * @return {@code true} if this {@code Calendar} supports week dates;
+     *         {@code false} otherwise.
+     * @see #getWeekYear()
+     * @see #setWeekDate(int,int,int)
+     * @see #getWeeksInWeekYear()
+     * @since 1.7
+     */
+    public boolean isWeekDateSupported() {
+        return false;
+    }
+
+    /**
+     * Returns the week year represented by this {@code Calendar}. The
+     * week year is in sync with the week cycle. The {@linkplain
+     * #getFirstDayOfWeek() first day of the first week} is the first
+     * day of the week year.
+     *
+     * <p>The default implementation of this method throws an
+     * {@link UnsupportedOperationException}.
+     *
+     * @return the week year of this {@code Calendar}
+     * @exception UnsupportedOperationException
+     *            if any week year numbering isn't supported
+     *            in this {@code Calendar}.
+     * @see #isWeekDateSupported()
+     * @see #getFirstDayOfWeek()
+     * @see #getMinimalDaysInFirstWeek()
+     * @since 1.7
+     */
+    public int getWeekYear() {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Sets the date of this {@code Calendar} with the the given date
+     * specifiers - week year, week of year, and day of week.
+     *
+     * <p>Unlike the {@code set} method, all of the calendar fields
+     * and {@code time} values are calculated upon return.
+     *
+     * <p>If {@code weekOfYear} is out of the valid week-of-year range
+     * in {@code weekYear}, the {@code weekYear} and {@code
+     * weekOfYear} values are adjusted in lenient mode, or an {@code
+     * IllegalArgumentException} is thrown in non-lenient mode.
+     *
+     * <p>The default implementation of this method throws an
+     * {@code UnsupportedOperationException}.
+     *
+     * @param weekYear   the week year
+     * @param weekOfYear the week number based on {@code weekYear}
+     * @param dayOfWeek  the day of week value: one of the constants
+     *                   for the {@link #DAY_OF_WEEK} field: {@link
+     *                   #SUNDAY}, ..., {@link #SATURDAY}.
+     * @exception IllegalArgumentException
+     *            if any of the given date specifiers is invalid
+     *            or any of the calendar fields are inconsistent
+     *            with the given date specifiers in non-lenient mode
+     * @exception UnsupportedOperationException
+     *            if any week year numbering isn't supported in this
+     *            {@code Calendar}.
+     * @see #isWeekDateSupported()
+     * @see #getFirstDayOfWeek()
+     * @see #getMinimalDaysInFirstWeek()
+     * @since 1.7
+     */
+    public void setWeekDate(int weekYear, int weekOfYear, int dayOfWeek) {
+        throw new UnsupportedOperationException();
+    }
+
+    /**
+     * Returns the number of weeks in the week year represented by this
+     * {@code Calendar}.
+     *
+     * <p>The default implementation of this method throws an
+     * {@code UnsupportedOperationException}.
+     *
+     * @return the number of weeks in the week year.
+     * @exception UnsupportedOperationException
+     *            if any week year numbering isn't supported in this
+     *            {@code Calendar}.
+     * @see #WEEK_OF_YEAR
+     * @see #isWeekDateSupported()
+     * @see #getWeekYear()
+     * @see #getActualMaximum(int)
+     * @since 1.7
+     */
+    public int getWeeksInWeekYear() {
+        throw new UnsupportedOperationException();
+    }
+
     /**
      * Returns the minimum value for the given calendar field of this
      * <code>Calendar</code> instance. The minimum value is defined as

test/java/text/Format/DateFormat/WeekDateTest.java

+/*
+ * Copyright (c) 2010, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 4267450
+ * @summary Unit test for week date support
+ */
+
+import java.text.*;
+import java.util.*;
+import static java.util.GregorianCalendar.*;
+
+public class WeekDateTest {
+    static SimpleDateFormat ymdFormat = new SimpleDateFormat("yyyy-MM-dd");
+    static SimpleDateFormat ywdFormat = new SimpleDateFormat("YYYY-'W'ww-u");
+    static {
+        ymdFormat.setCalendar(newCalendar());
+        ywdFormat.setCalendar(newCalendar());
+    }
+
+    // Round-trip Data
+    static final String[][] roundTripData = {
+        { "2005-01-01", "2004-W53-6" },
+        { "2005-01-02", "2004-W53-7" },
+        { "2005-12-31", "2005-W52-6" },
+        { "2007-01-01", "2007-W01-1" },
+        { "2007-12-30", "2007-W52-7" },
+        { "2007-12-31", "2008-W01-1" },
+        { "2008-01-01", "2008-W01-2" },
+        { "2008-12-29", "2009-W01-1" },
+        { "2008-12-31", "2009-W01-3" },
+        { "2009-01-01", "2009-W01-4" },
+        { "2009-12-31", "2009-W53-4" },
+        { "2010-01-03", "2009-W53-7" },
+        { "2009-12-31", "2009-W53-4" },
+        { "2010-01-01", "2009-W53-5" },
+        { "2010-01-02", "2009-W53-6" },
+        { "2010-01-03", "2009-W53-7" },
+        { "2008-12-28", "2008-W52-7" },
+        { "2008-12-29", "2009-W01-1" },
+        { "2008-12-30", "2009-W01-2" },
+        { "2008-12-31", "2009-W01-3" },
+        { "2009-01-01", "2009-W01-4" },
+        { "2009-01-01", "2009-W01-4" },
+    };
+
+    // Data for leniency test
+    static final String[][] leniencyData = {
+        { "2008-12-28", "2009-W01-0" },
+        { "2010-01-04", "2009-W53-8" },
+        { "2008-12-29", "2008-W53-1" },
+    };
+
+    static final String[] invalidData = {
+        "2010-W00-1",
+        "2010-W55-1",
+        "2010-W03-0",
+        "2010-W04-8",
+        "2010-W04-19"
+    };
+
+    public static void main(String[] args) throws Exception {
+        formatTest(roundTripData);
+        parseTest(roundTripData);
+        parseTest(leniencyData);
+        nonLenientTest(invalidData);
+        noWeekDateSupport();
+    }
+
+    private static void formatTest(String[][] data) throws Exception {
+        for (String[] dates : data) {
+            String regularDate = dates[0];
+            String weekDate = dates[1];
+            Date date = null;
+            date = ymdFormat.parse(regularDate);
+            String s = ywdFormat.format(date);
+            if (!s.equals(weekDate)) {
+                throw new RuntimeException("format: got="+s+", expecetd="+weekDate);
+            }
+        }
+    }
+
+    private static void parseTest(String[][] data) throws Exception {
+        for (String[] dates : data) {
+            String regularDate = dates[0];
+            String weekDate = dates[1];
+            Date date1 = null, date2 = null;
+            date1 = ymdFormat.parse(regularDate);
+            date2 = ywdFormat.parse(weekDate);
+            if (!date1.equals(date2)) {
+                System.err.println(regularDate + ": date1 = " + date1);
+                System.err.println(weekDate + ": date2 = " + date2);
+                throw new RuntimeException("parse: date1 != date2");
+            }
+        }
+    }
+
+
+    // Non-lenient mode test
+    private static void nonLenientTest(String[] data) {
+        ywdFormat.setLenient(false);
+        for (String date : data) {
+            try {
+                Date d = ywdFormat.parse(date);
+                throw new RuntimeException("No ParseException thrown with " + date);
+            } catch (ParseException e) {
+                // OK
+            }
+        }
+        ywdFormat.setLenient(true);
+    }
+
+
+    private static void noWeekDateSupport() throws Exception {
+        // Tests with Japanese Imperial Calendar that doesn't support week dates.
+        Calendar jcal = Calendar.getInstance(TimeZone.getTimeZone("GMT"),
+                                             new Locale("ja", "JP", "JP"));
+
+        jcal.setFirstDayOfWeek(MONDAY);
+        jcal.setMinimalDaysInFirstWeek(4);
+        SimpleDateFormat sdf = new SimpleDateFormat("Y-'W'ww-u");
+        sdf.setCalendar(jcal);
+        Date d = sdf.parse("21-W01-3"); // 2008-12-31 == H20-12-31
+        GregorianCalendar gcal = newCalendar();
+        gcal.setTime(d);
+        if (gcal.get(YEAR) != 2008
+            || gcal.get(MONTH) != DECEMBER
+            || gcal.get(DAY_OF_MONTH) != 31) {
+            String s = String.format("noWeekDateSupport: got %04d-%02d-%02d, expected 2008-12-31%n",
+                                     gcal.get(YEAR),
+                                     gcal.get(MONTH)+1,
+                                     gcal.get(DAY_OF_MONTH));
+            throw new RuntimeException(s);
+        }
+    }
+
+    private static GregorianCalendar newCalendar() {
+        // Use GMT to avoid any surprises related DST transitions.
+        GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
+        // Setup the ISO 8601 compatible parameters
+        cal.setFirstDayOfWeek(MONDAY);
+        cal.setMinimalDaysInFirstWeek(4);
+        return cal;
+    }
+}

test/java/util/Calendar/WeekDateTest.java

+/*
+ * Copyright (c) 2010, 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.
+ *
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 4267450
+ * @summary Unit test for week date support
+ */
+
+import java.text.*;
+import java.util.*;
+import static java.util.GregorianCalendar.*;
+
+public class WeekDateTest {
+
+    // Week dates are in the ISO numbering for day-of-week.
+    static int[][][] data = {
+        // Calendar year-date, Week year-date
+        {{ 2005, 01, 01}, {2004, 53, 6}},
+        {{ 2005, 01, 02}, {2004, 53, 7}},
+        {{ 2005, 12, 31}, {2005, 52, 6}},
+        {{ 2007, 01, 01}, {2007, 01, 1}},
+        {{ 2007, 12, 30}, {2007, 52, 7}},
+        {{ 2007, 12, 31}, {2008, 01, 1}},
+        {{ 2008, 01, 01}, {2008, 01, 2}},
+        {{ 2008, 12, 29}, {2009, 01, 1}},
+        {{ 2008, 12, 31}, {2009, 01, 3}},
+        {{ 2009, 01, 01}, {2009, 01, 4}},
+        {{ 2009, 12, 31}, {2009, 53, 4}},
+        {{ 2010, 01, 03}, {2009, 53, 7}},
+        {{ 2009, 12, 31}, {2009, 53, 4}},
+        {{ 2010, 01, 01}, {2009, 53, 5}},
+        {{ 2010, 01, 02}, {2009, 53, 6}},
+        {{ 2010, 01, 03}, {2009, 53, 7}},
+        {{ 2008, 12, 28}, {2008, 52, 7}},
+        {{ 2008, 12, 29}, {2009, 01, 1}},
+        {{ 2008, 12, 30}, {2009, 01, 2}},
+        {{ 2008, 12, 31}, {2009, 01, 3}},
+        {{ 2009, 01, 01}, {2009, 01, 4}}
+    };
+
+    public static void main(String[] args) {
+        GregorianCalendar cal = newCalendar();
+        for (int[][] dates : data) {
+            int[] expected = dates[0];
+            int[] weekDate = dates[1];
+            // Convert ISO 8601 day-of-week to Calendar.DAY_OF_WEEK.
+            int dayOfWeek = weekDate[2] == 7 ? SUNDAY : weekDate[2] + 1;
+
+            cal.clear();
+            cal.setWeekDate(weekDate[0], weekDate[1], dayOfWeek);
+            if (cal.get(YEAR) != expected[0]
+                || cal.get(MONTH)+1 != expected[1]
+                || cal.get(DAY_OF_MONTH) != expected[2]) {
+                String s = String.format("got=%4d-%02d-%02d, expected=%4d-%02d-%02d",
+                               cal.get(YEAR), cal.get(MONTH)+1, cal.get(DAY_OF_MONTH),
+                               expected[0], expected[1], expected[2]);
+                throw new RuntimeException(s);
+            }
+            if (cal.getWeekYear() != weekDate[0]
+                || cal.get(WEEK_OF_YEAR) != weekDate[1]
+                || cal.get(DAY_OF_WEEK) != dayOfWeek) {
+                String s = String.format(
+                    "got=%4d-W%02d-%d, expected=%4d-W%02d-%d (not ISO day-of-week)",
+                    cal.getWeekYear(), cal.get(WEEK_OF_YEAR), cal.get(DAY_OF_WEEK),
+                    weekDate[0], weekDate[1], dayOfWeek);
+                throw new RuntimeException(s);
+            }
+        }
+
+        // Test getWeeksInWeekYear().
+        // If we avoid the first week of January and the last week of
+        // December, getWeeksInWeekYear() and
+        // getActualMaximum(WEEK_OF_YEAR) values should be the same.
+        for (int year = 2000; year <= 2100; year++) {
+            cal.clear();
+            cal.set(year, JUNE, 1);
+            int n = cal.getWeeksInWeekYear();
+            if (n != cal.getActualMaximum(WEEK_OF_YEAR)) {
+                String s = String.format("getWeeksInWeekYear() = %d, "
+                                         + "getActualMaximum(WEEK_OF_YEAR) = %d%n",
+                                         n, cal.getActualMaximum(WEEK_OF_YEAR));
+                throw new RuntimeException(s);
+            }
+            cal.setWeekDate(cal.getWeekYear(), 1, MONDAY);
+            System.out.println(cal.getTime());
+            if (cal.getWeeksInWeekYear() != n) {
+                String s = String.format("first day: got %d, expected %d%n",
+                                         cal.getWeeksInWeekYear(), n);
+                throw new RuntimeException(s);
+            }
+            cal.setWeekDate(cal.getWeekYear(), n, SUNDAY);
+            System.out.println(cal.getTime());
+            if (cal.getWeeksInWeekYear() != n) {
+                String s = String.format("last day: got %d, expected %d%n",
+                                         cal.getWeeksInWeekYear(), n);
+                throw new RuntimeException(s);
+            }
+        }
+    }
+
+    private static GregorianCalendar newCalendar() {
+        // Use GMT to avoid any surprises related DST transitions.
+        GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
+        if (!cal.isWeekDateSupported()) {
+            throw new RuntimeException("Week dates not supported");
+        }
+        // Setup the ISO 8601 compatible parameters
+        cal.setFirstDayOfWeek(MONDAY);
+        cal.setMinimalDaysInFirstWeek(4);
+        return cal;
+    }
+}