changeset 20519:eee7a92074fd

8023762: Add ChronoPeriod interface and bind period to Chronology Summary: Make Period ISO-only, adding a Chronology-specific period concept Reviewed-by: sherman Contributed-by: scolebourne@joda.org
author rriggs
date Wed, 04 Sep 2013 15:18:54 +0100
parents dde564773845
children 0952771e3e25
files jdk/src/share/classes/java/time/LocalDate.java jdk/src/share/classes/java/time/Period.java jdk/src/share/classes/java/time/chrono/ChronoLocalDate.java jdk/src/share/classes/java/time/chrono/ChronoPeriod.java jdk/src/share/classes/java/time/chrono/ChronoPeriodImpl.java jdk/src/share/classes/java/time/chrono/Chronology.java jdk/src/share/classes/java/time/chrono/HijrahDate.java jdk/src/share/classes/java/time/chrono/IsoChronology.java jdk/src/share/classes/java/time/chrono/JapaneseDate.java jdk/src/share/classes/java/time/chrono/MinguoDate.java jdk/src/share/classes/java/time/chrono/Ser.java jdk/src/share/classes/java/time/chrono/ThaiBuddhistDate.java jdk/src/share/classes/java/time/temporal/Temporal.java jdk/test/java/time/tck/java/time/TCKPeriod.java jdk/test/java/time/tck/java/time/chrono/TCKChronoPeriod.java jdk/test/java/time/tck/java/time/chrono/TCKJapaneseChronology.java jdk/test/java/time/tck/java/time/chrono/TCKMinguoChronology.java jdk/test/java/time/tck/java/time/chrono/TCKThaiBuddhistChronology.java jdk/test/java/time/test/java/time/chrono/TestUmmAlQuraChronology.java
diffstat 19 files changed, 1390 insertions(+), 140 deletions(-) [+]
line wrap: on
line diff
--- a/jdk/src/share/classes/java/time/LocalDate.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/LocalDate.java	Wed Sep 04 15:18:54 2013 +0100
@@ -1642,12 +1642,12 @@
      * </pre>
      * The choice should be made based on which makes the code more readable.
      *
-     * @param endDate  the end date, exclusive, which may be in any chronology, not null
+     * @param endDateExclusive  the end date, exclusive, which may be in any chronology, not null
      * @return the period between this date and the end date, not null
      */
     @Override
-    public Period until(ChronoLocalDate endDate) {
-        LocalDate end = LocalDate.from(endDate);
+    public Period until(ChronoLocalDate endDateExclusive) {
+        LocalDate end = LocalDate.from(endDateExclusive);
         long totalMonths = end.getProlepticMonth() - this.getProlepticMonth();  // safe
         int days = end.day - this.day;
         if (totalMonths > 0 && days < 0) {
--- a/jdk/src/share/classes/java/time/Period.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/Period.java	Wed Sep 04 15:18:54 2013 +0100
@@ -61,7 +61,6 @@
  */
 package java.time;
 
-import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
 import static java.time.temporal.ChronoUnit.DAYS;
 import static java.time.temporal.ChronoUnit.MONTHS;
 import static java.time.temporal.ChronoUnit.YEARS;
@@ -70,17 +69,19 @@
 import java.io.DataOutput;
 import java.io.IOException;
 import java.io.InvalidObjectException;
-import java.io.InvalidObjectException;
 import java.io.Serializable;
 import java.time.chrono.ChronoLocalDate;
+import java.time.chrono.ChronoPeriod;
 import java.time.chrono.Chronology;
+import java.time.chrono.IsoChronology;
 import java.time.format.DateTimeParseException;
 import java.time.temporal.ChronoUnit;
 import java.time.temporal.Temporal;
+import java.time.temporal.TemporalAccessor;
 import java.time.temporal.TemporalAmount;
+import java.time.temporal.TemporalQuery;
 import java.time.temporal.TemporalUnit;
 import java.time.temporal.UnsupportedTemporalTypeException;
-import java.time.temporal.ValueRange;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -89,12 +90,13 @@
 import java.util.regex.Pattern;
 
 /**
- * A date-based amount of time, such as '2 years, 3 months and 4 days'.
+ * A date-based amount of time in the ISO-8601 calendar system,
+ * such as '2 years, 3 months and 4 days'.
  * <p>
  * This class models a quantity or amount of time in terms of years, months and days.
  * See {@link Duration} for the time-based equivalent to this class.
  * <p>
- * Durations and period differ in their treatment of daylight savings time
+ * Durations and periods differ in their treatment of daylight savings time
  * when added to {@link ZonedDateTime}. A {@code Duration} will add an exact
  * number of seconds, thus a duration of one day is always exactly 24 hours.
  * By contrast, a {@code Period} will add a conceptual day, trying to maintain
@@ -110,14 +112,12 @@
  * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}.
  * All three fields are always present, but may be set to zero.
  * <p>
- * The period may be used with any calendar system.
- * The meaning of a "year" or "month" is only applied when the object is added to a date.
+ * The ISO-8601 calendar system is the modern civil calendar system used today
+ * in most of the world. It is equivalent to the proleptic Gregorian calendar
+ * system, in which today's rules for leap years are applied for all time.
  * <p>
  * The period is modeled as a directed amount of time, meaning that individual parts of the
  * period may be negative.
- * <p>
- * The months and years fields may be {@linkplain #normalized() normalized}.
- * The normalization assumes a 12 month year, so is not appropriate for all calendar systems.
  *
  * @implSpec
  * This class is immutable and thread-safe.
@@ -125,7 +125,7 @@
  * @since 1.8
  */
 public final class Period
-        implements TemporalAmount, Serializable {
+        implements ChronoPeriod, Serializable {
 
     /**
      * A constant for a period of zero.
@@ -140,6 +140,7 @@
      */
     private final static Pattern PATTERN =
             Pattern.compile("([-+]?)P(?:([-+]?[0-9]+)Y)?(?:([-+]?[0-9]+)M)?(?:([-+]?[0-9]+)W)?(?:([-+]?[0-9]+)D)?", Pattern.CASE_INSENSITIVE);
+
     /**
      * The set of supported units.
      */
@@ -234,12 +235,14 @@
      * <p>
      * This obtains a period based on the specified amount.
      * A {@code TemporalAmount} represents an  amount of time, which may be
-     * date-based or time-based, which this factory extracts to a period.
+     * date-based or time-based, which this factory extracts to a {@code Period}.
      * <p>
      * The conversion loops around the set of units from the amount and uses
      * the {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS}
      * and {@link ChronoUnit#DAYS DAYS} units to create a period.
      * If any other units are found then an exception is thrown.
+     * <p>
+     * If the amount is a {@code ChronoPeriod} then it must use the ISO chronology.
      *
      * @param amount  the temporal amount to convert, not null
      * @return the equivalent period, not null
@@ -247,6 +250,14 @@
      * @throws ArithmeticException if the amount of years, months or days exceeds an int
      */
     public static Period from(TemporalAmount amount) {
+        if (amount instanceof Period) {
+            return (Period) amount;
+        }
+        if (amount instanceof ChronoPeriod) {
+            if (IsoChronology.INSTANCE.equals(((ChronoPeriod) amount).getChronology()) == false) {
+                throw new DateTimeException("Period requires ISO chronology: " + amount);
+            }
+        }
         Objects.requireNonNull(amount, "amount");
         int years = 0;
         int months = 0;
@@ -358,13 +369,13 @@
      * The result of this method can be a negative period if the end is before the start.
      * The negative sign will be the same in each of year, month and day.
      *
-     * @param startDate  the start date, inclusive, not null
-     * @param endDate  the end date, exclusive, not null
+     * @param startDateInclusive  the start date, inclusive, not null
+     * @param endDateExclusive  the end date, exclusive, not null
      * @return the period between this date and the end date, not null
      * @see ChronoLocalDate#until(ChronoLocalDate)
      */
-    public static Period between(LocalDate startDate, LocalDate endDate) {
-        return startDate.until(endDate);
+    public static Period between(LocalDate startDateInclusive, LocalDate endDateExclusive) {
+        return startDateInclusive.until(endDateExclusive);
     }
 
     //-----------------------------------------------------------------------
@@ -439,6 +450,21 @@
         return SUPPORTED_UNITS;
     }
 
+    /**
+     * Gets the chronology of this period, which is the ISO calendar system.
+     * <p>
+     * The {@code Chronology} represents the calendar system in use.
+     * The ISO-8601 calendar system is the modern civil calendar system used today
+     * in most of the world. It is equivalent to the proleptic Gregorian calendar
+     * system, in which today's rules for leap years are applied for all time.
+     *
+     * @return the ISO chronology, not null
+     */
+    @Override
+    public IsoChronology getChronology() {
+        return IsoChronology.INSTANCE;
+    }
+
     //-----------------------------------------------------------------------
     /**
      * Checks if all three units of this period are zero.
@@ -468,7 +494,7 @@
      * <p>
      * This returns the years unit.
      * <p>
-     * The months unit is not normalized with the years unit.
+     * The months unit is not automatically normalized with the years unit.
      * This means that a period of "15 months" is different to a period
      * of "1 year and 3 months".
      *
@@ -483,7 +509,7 @@
      * <p>
      * This returns the months unit.
      * <p>
-     * The months unit is not normalized with the years unit.
+     * The months unit is not automatically normalized with the years unit.
      * This means that a period of "15 months" is different to a period
      * of "1 year and 3 months".
      *
@@ -511,7 +537,7 @@
      * This sets the amount of the years unit in a copy of this period.
      * The months and days units are unaffected.
      * <p>
-     * The months unit is not normalized with the years unit.
+     * The months unit is not automatically normalized with the years unit.
      * This means that a period of "15 months" is different to a period
      * of "1 year and 3 months".
      * <p>
@@ -533,7 +559,7 @@
      * This sets the amount of the months unit in a copy of this period.
      * The years and days units are unaffected.
      * <p>
-     * The months unit is not normalized with the years unit.
+     * The months unit is not automatically normalized with the years unit.
      * This means that a period of "15 months" is different to a period
      * of "1 year and 3 months".
      * <p>
@@ -572,21 +598,28 @@
      * Returns a copy of this period with the specified period added.
      * <p>
      * This operates separately on the years, months and days.
+     * No normalization is performed.
      * <p>
      * For example, "1 year, 6 months and 3 days" plus "2 years, 2 months and 2 days"
      * returns "3 years, 8 months and 5 days".
      * <p>
+     * The specified amount is typically an instance of {@code Period}.
+     * Other types are interpreted using {@link Period#from(TemporalAmount)}.
+     * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param amountToAdd  the period to add, not null
      * @return a {@code Period} based on this period with the requested period added, not null
+     * @throws DateTimeException if the specified amount has a non-ISO chronology or
+     *  contains an invalid unit
      * @throws ArithmeticException if numeric overflow occurs
      */
-    public Period plus(Period amountToAdd) {
+    public Period plus(TemporalAmount amountToAdd) {
+        Period isoAmount = Period.from(amountToAdd);
         return create(
-                Math.addExact(years, amountToAdd.years),
-                Math.addExact(months, amountToAdd.months),
-                Math.addExact(days, amountToAdd.days));
+                Math.addExact(years, isoAmount.years),
+                Math.addExact(months, isoAmount.months),
+                Math.addExact(days, isoAmount.days));
     }
 
     /**
@@ -654,21 +687,28 @@
      * Returns a copy of this period with the specified period subtracted.
      * <p>
      * This operates separately on the years, months and days.
+     * No normalization is performed.
      * <p>
      * For example, "1 year, 6 months and 3 days" minus "2 years, 2 months and 2 days"
      * returns "-1 years, 4 months and 1 day".
      * <p>
+     * The specified amount is typically an instance of {@code Period}.
+     * Other types are interpreted using {@link Period#from(TemporalAmount)}.
+     * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @param amountToSubtract  the period to subtract, not null
      * @return a {@code Period} based on this period with the requested period subtracted, not null
+     * @throws DateTimeException if the specified amount has a non-ISO chronology or
+     *  contains an invalid unit
      * @throws ArithmeticException if numeric overflow occurs
      */
-    public Period minus(Period amountToSubtract) {
+    public Period minus(TemporalAmount amountToSubtract) {
+        Period isoAmount = Period.from(amountToSubtract);
         return create(
-                Math.subtractExact(years, amountToSubtract.years),
-                Math.subtractExact(months, amountToSubtract.months),
-                Math.subtractExact(days, amountToSubtract.days));
+                Math.subtractExact(years, isoAmount.years),
+                Math.subtractExact(months, isoAmount.months),
+                Math.subtractExact(days, isoAmount.days));
     }
 
     /**
@@ -766,8 +806,7 @@
 
     //-----------------------------------------------------------------------
     /**
-     * Returns a copy of this period with the years and months normalized
-     * using a 12 month year.
+     * Returns a copy of this period with the years and months normalized.
      * <p>
      * This normalizes the years and months units, leaving the days unit unchanged.
      * The months unit is adjusted to have an absolute value less than 11,
@@ -778,8 +817,6 @@
      * For example, a period of "1 year and -25 months" will be normalized to
      * "-1 year and -1 month".
      * <p>
-     * This normalization uses a 12 month year which is not valid for all calendar systems.
-     * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @return a {@code Period} based on this period with excess months normalized to years, not null
@@ -796,13 +833,11 @@
     }
 
     /**
-     * Gets the total number of months in this period using a 12 month year.
+     * Gets the total number of months in this period.
      * <p>
      * This returns the total number of months in the period by multiplying the
      * number of years by 12 and adding the number of months.
      * <p>
-     * This uses a 12 month year which is not valid for all calendar systems.
-     * <p>
      * This instance is immutable and unaffected by this method call.
      *
      * @return the total number of months in the period, may be negative
@@ -817,6 +852,7 @@
      * <p>
      * This returns a temporal object of the same observable type as the input
      * with this period added.
+     * If the temporal has a chronology, it must be the ISO chronology.
      * <p>
      * In most cases, it is clearer to reverse the calling pattern by using
      * {@link Temporal#plus(TemporalAmount)}.
@@ -826,10 +862,17 @@
      *   dateTime = dateTime.plus(thisPeriod);
      * </pre>
      * <p>
-     * The calculation will add the years, then months, then days.
-     * Only non-zero amounts will be added.
-     * If the date-time has a calendar system with a fixed number of months in a
-     * year, then the years and months will be combined before being added.
+     * The calculation operates as follows.
+     * First, the chronology of the temporal is checked to ensure it is ISO chronology or null.
+     * Second, if the months are zero, the years are added if non-zero, otherwise
+     * the combination of years and months is added if non-zero.
+     * Finally, any days are added.
+     * <p>
+     * This approach ensures that a partial period can be added to a partial date.
+     * For example, a period of years and/or months can be added to a {@code YearMonth},
+     * but a period including days cannot.
+     * The approach also adds years and months together when necessary, which ensures
+     * correct behaviour at the end of the month.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
@@ -840,18 +883,15 @@
      */
     @Override
     public Temporal addTo(Temporal temporal) {
-        Objects.requireNonNull(temporal, "temporal");
-        if ((years | months) != 0) {
-            long monthRange = monthRange(temporal);
-            if (monthRange >= 0) {
-                temporal = temporal.plus(years * monthRange + months, MONTHS);
-            } else {
-                if (years != 0) {
-                    temporal = temporal.plus(years, YEARS);
-                }
-                if (months != 0) {
-                    temporal = temporal.plus(months, MONTHS);
-                }
+        validateChrono(temporal);
+        if (months == 0) {
+            if (years != 0) {
+                temporal = temporal.plus(years, YEARS);
+            }
+        } else {
+            long totalMonths = toTotalMonths();
+            if (totalMonths != 0) {
+                temporal = temporal.plus(totalMonths, MONTHS);
             }
         }
         if (days != 0) {
@@ -865,6 +905,7 @@
      * <p>
      * This returns a temporal object of the same observable type as the input
      * with this period subtracted.
+     * If the temporal has a chronology, it must be the ISO chronology.
      * <p>
      * In most cases, it is clearer to reverse the calling pattern by using
      * {@link Temporal#minus(TemporalAmount)}.
@@ -874,10 +915,17 @@
      *   dateTime = dateTime.minus(thisPeriod);
      * </pre>
      * <p>
-     * The calculation will subtract the years, then months, then days.
-     * Only non-zero amounts will be subtracted.
-     * If the date-time has a calendar system with a fixed number of months in a
-     * year, then the years and months will be combined before being subtracted.
+     * The calculation operates as follows.
+     * First, the chronology of the temporal is checked to ensure it is ISO chronology or null.
+     * Second, if the months are zero, the years are subtracted if non-zero, otherwise
+     * the combination of years and months is subtracted if non-zero.
+     * Finally, any days are subtracted.
+     * <p>
+     * This approach ensures that a partial period can be subtracted from a partial date.
+     * For example, a period of years and/or months can be subtracted from a {@code YearMonth},
+     * but a period including days cannot.
+     * The approach also subtracts years and months together when necessary, which ensures
+     * correct behaviour at the end of the month.
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
@@ -888,18 +936,15 @@
      */
     @Override
     public Temporal subtractFrom(Temporal temporal) {
-        Objects.requireNonNull(temporal, "temporal");
-        if ((years | months) != 0) {
-            long monthRange = monthRange(temporal);
-            if (monthRange >= 0) {
-                temporal = temporal.minus(years * monthRange + months, MONTHS);
-            } else {
-                if (years != 0) {
-                    temporal = temporal.minus(years, YEARS);
-                }
-                if (months != 0) {
-                    temporal = temporal.minus(months, MONTHS);
-                }
+        validateChrono(temporal);
+        if (months == 0) {
+            if (years != 0) {
+                temporal = temporal.minus(years, YEARS);
+            }
+        } else {
+            long totalMonths = toTotalMonths();
+            if (totalMonths != 0) {
+                temporal = temporal.minus(totalMonths, MONTHS);
             }
         }
         if (days != 0) {
@@ -909,26 +954,21 @@
     }
 
     /**
-     * Calculates the range of months based on the temporal.
-     *
-     * @param temporal  the temporal, not null
-     * @return the month range, negative if not fixed range
+     * Validates that the temporal has the correct chronology.
      */
-    private long monthRange(Temporal temporal) {
-        if (temporal.isSupported(MONTH_OF_YEAR)) {
-            ValueRange startRange = Chronology.from(temporal).range(MONTH_OF_YEAR);
-            if (startRange.isFixed() && startRange.isIntValue()) {
-                return startRange.getMaximum() - startRange.getMinimum() + 1;
-            }
+    private void validateChrono(TemporalAccessor temporal) {
+        Objects.requireNonNull(temporal, "temporal");
+        Chronology temporalChrono = temporal.query(TemporalQuery.chronology());
+        if (temporalChrono != null && IsoChronology.INSTANCE.equals(temporalChrono) == false) {
+            throw new DateTimeException("Chronology mismatch, expected: ISO, actual: " + temporalChrono.getId());
         }
-        return -1;
     }
 
     //-----------------------------------------------------------------------
     /**
      * Checks if this period is equal to another period.
      * <p>
-     * The comparison is based on the amounts held in the period.
+     * The comparison is based on the type {@code Period} and each of the three amounts.
      * To be equal, the years, months and days units must be individually equal.
      * Note that this means that a period of "15 Months" is not equal to a period
      * of "1 Year and 3 Months".
--- a/jdk/src/share/classes/java/time/chrono/ChronoLocalDate.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/ChronoLocalDate.java	Wed Sep 04 15:18:54 2013 +0100
@@ -69,7 +69,6 @@
 import java.time.DateTimeException;
 import java.time.LocalDate;
 import java.time.LocalTime;
-import java.time.Period;
 import java.time.format.DateTimeFormatter;
 import java.time.temporal.ChronoField;
 import java.time.temporal.ChronoUnit;
@@ -602,9 +601,12 @@
     long until(Temporal endDate, TemporalUnit unit);
 
     /**
-     * Calculates the period between this date and another date as a {@code Period}.
+     * Calculates the period between this date and another date as a {@code ChronoPeriod}.
      * <p>
-     * This calculates the period between two dates in terms of years, months and days.
+     * This calculates the period between two dates. All supplied chronologies
+     * calculate the period using years, months and days, however the
+     * {@code ChronoPeriod} API allows the period to be represented using other units.
+     * <p>
      * The start and end points are {@code this} and the specified date.
      * The result will be negative if the end is before the start.
      * The negative sign will be the same in each of year, month and day.
@@ -614,12 +616,12 @@
      * <p>
      * This instance is immutable and unaffected by this method call.
      *
-     * @param endDate  the end date, exclusive, which may be in any chronology, not null
+     * @param endDateExclusive  the end date, exclusive, which may be in any chronology, not null
      * @return the period between this date and the end date, not null
      * @throws DateTimeException if the period cannot be calculated
      * @throws ArithmeticException if numeric overflow occurs
      */
-    Period until(ChronoLocalDate endDate);
+    ChronoPeriod until(ChronoLocalDate endDateExclusive);
 
     /**
      * Formats this date using the specified formatter.
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/time/chrono/ChronoPeriod.java	Wed Sep 04 15:18:54 2013 +0100
@@ -0,0 +1,365 @@
+/*
+ * Copyright (c) 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) 2013, 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.chrono;
+
+import java.time.DateTimeException;
+import java.time.temporal.ChronoUnit;
+import java.time.temporal.Temporal;
+import java.time.temporal.TemporalAmount;
+import java.time.temporal.TemporalUnit;
+import java.time.temporal.UnsupportedTemporalTypeException;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * A date-based amount of time, such as '3 years, 4 months and 5 days' in an
+ * arbitrary chronology, intended for advanced globalization use cases.
+ * <p>
+ * This interface models a date-based amount of time in a calendar system.
+ * While most calendar systems use years, months and days, some do not.
+ * Therefore, this interface operates solely in terms of a set of supported
+ * units that are defined by the {@code Chronology}.
+ * The set of supported units is fixed for a given chronology.
+ * The amount of a supported unit may be set to zero.
+ * <p>
+ * The period is modeled as a directed amount of time, meaning that individual
+ * parts of the period may be negative.
+ *
+ * @implSpec
+ * This interface must be implemented with care to ensure other classes operate correctly.
+ * All implementations that can be instantiated must be final, immutable and thread-safe.
+ * Subclasses should be Serializable wherever possible.
+ *
+ * @since 1.8
+ */
+public interface ChronoPeriod
+        extends TemporalAmount {
+
+    /**
+     * Obtains a {@code ChronoPeriod} consisting of amount of time between two dates.
+     * <p>
+     * The start date is included, but the end date is not.
+     * The period is calculated using {@link ChronoLocalDate#until(ChronoLocalDate)}.
+     * As such, the calculation is chronology specific.
+     * <p>
+     * The chronology of the first date is used.
+     * The chronology of the second date is ignored, with the date being converted
+     * to the target chronology system before the calculation starts.
+     * <p>
+     * The result of this method can be a negative period if the end is before the start.
+     * In most cases, the positive/negative sign will be the same in each of the supported fields.
+     *
+     * @param startDateInclusive  the start date, inclusive, specifying the chronology of the calculation, not null
+     * @param endDateExclusive  the end date, exclusive, in any chronology, not null
+     * @return the period between this date and the end date, not null
+     * @see ChronoLocalDate#until(ChronoLocalDate)
+     */
+    public static ChronoPeriod between(ChronoLocalDate startDateInclusive, ChronoLocalDate endDateExclusive) {
+        Objects.requireNonNull(startDateInclusive, "startDateInclusive");
+        Objects.requireNonNull(endDateExclusive, "endDateExclusive");
+        return startDateInclusive.until(endDateExclusive);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the value of the requested unit.
+     * <p>
+     * The supported units are chronology specific.
+     * They will typically be {@link ChronoUnit#YEARS YEARS},
+     * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}.
+     * Requesting an unsupported unit will throw an exception.
+     *
+     * @param unit the {@code TemporalUnit} for which to return the value
+     * @return the long value of the unit
+     * @throws DateTimeException if the unit is not supported
+     * @throws UnsupportedTemporalTypeException if the unit is not supported
+     */
+    @Override
+    long get(TemporalUnit unit);
+
+    /**
+     * Gets the set of units supported by this period.
+     * <p>
+     * The supported units are chronology specific.
+     * They will typically be {@link ChronoUnit#YEARS YEARS},
+     * {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}.
+     * They are returned in order from largest to smallest.
+     * <p>
+     * This set can be used in conjunction with {@link #get(TemporalUnit)}
+     * to access the entire state of the period.
+     *
+     * @return a list containing the supported units, not null
+     */
+    @Override
+    List<TemporalUnit> getUnits();
+
+    /**
+     * Gets the chronology that defines the meaning of the supported units.
+     * <p>
+     * The period is defined by the chronology.
+     * It controls the supported units and restricts addition/subtraction
+     * to {@code ChronoLocalDate} instances of the same chronology.
+     *
+     * @return the chronology defining the period, not null
+     */
+    Chronology getChronology();
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if all the supported units of this period are zero.
+     *
+     * @return true if this period is zero-length
+     */
+    default boolean isZero() {
+        for (TemporalUnit unit : getUnits()) {
+            if (get(unit) != 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Checks if any of the supported units of this period are negative.
+     *
+     * @return true if any unit of this period is negative
+     */
+    default boolean isNegative() {
+        for (TemporalUnit unit : getUnits()) {
+            if (get(unit) < 0) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns a copy of this period with the specified period added.
+     * <p>
+     * If the specified amount is a {@code ChronoPeriod} then it must have
+     * the same chronology as this period. Implementations may choose to
+     * accept or reject other {@code TemporalAmount} implementations.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param amountToAdd  the period to add, not null
+     * @return a {@code ChronoPeriod} based on this period with the requested period added, not null
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    ChronoPeriod plus(TemporalAmount amountToAdd);
+
+    /**
+     * Returns a copy of this period with the specified period subtracted.
+     * <p>
+     * If the specified amount is a {@code ChronoPeriod} then it must have
+     * the same chronology as this period. Implementations may choose to
+     * accept or reject other {@code TemporalAmount} implementations.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param amountToSubtract  the period to subtract, not null
+     * @return a {@code ChronoPeriod} based on this period with the requested period subtracted, not null
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    ChronoPeriod minus(TemporalAmount amountToSubtract);
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns a new instance with each amount in this period in this period
+     * multiplied by the specified scalar.
+     * <p>
+     * This returns a period with each supported unit individually multiplied.
+     * For example, a period of "2 years, -3 months and 4 days" multiplied by
+     * 3 will return "6 years, -9 months and 12 days".
+     * No normalization is performed.
+     *
+     * @param scalar  the scalar to multiply by, not null
+     * @return a {@code ChronoPeriod} based on this period with the amounts multiplied
+     *  by the scalar, not null
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    ChronoPeriod multipliedBy(int scalar);
+
+    /**
+     * Returns a new instance with each amount in this period negated.
+     * <p>
+     * This returns a period with each supported unit individually negated.
+     * For example, a period of "2 years, -3 months and 4 days" will be
+     * negated to "-2 years, 3 months and -4 days".
+     * No normalization is performed.
+     *
+     * @return a {@code ChronoPeriod} based on this period with the amounts negated, not null
+     * @throws ArithmeticException if numeric overflow occurs, which only happens if
+     *  one of the units has the value {@code Long.MIN_VALUE}
+     */
+    default ChronoPeriod negated() {
+        return multipliedBy(-1);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns a copy of this period with the amounts of each unit normalized.
+     * <p>
+     * The process of normalization is specific to each calendar system.
+     * For example, in the ISO calendar system, the years and months are
+     * normalized but the days are not, such that "15 months" would be
+     * normalized to "1 year and 3 months".
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @return a {@code ChronoPeriod} based on this period with the amounts of each
+     *  unit normalized, not null
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    ChronoPeriod normalized();
+
+    //-------------------------------------------------------------------------
+    /**
+     * Adds this period to the specified temporal object.
+     * <p>
+     * This returns a temporal object of the same observable type as the input
+     * with this period added.
+     * <p>
+     * In most cases, it is clearer to reverse the calling pattern by using
+     * {@link Temporal#plus(TemporalAmount)}.
+     * <pre>
+     *   // these two lines are equivalent, but the second approach is recommended
+     *   dateTime = thisPeriod.addTo(dateTime);
+     *   dateTime = dateTime.plus(thisPeriod);
+     * </pre>
+     * <p>
+     * The specified temporal must have the same chronology as this period.
+     * This returns a temporal with the non-zero supported units added.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param temporal  the temporal object to adjust, not null
+     * @return an object of the same type with the adjustment made, not null
+     * @throws DateTimeException if unable to add
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    @Override
+    Temporal addTo(Temporal temporal);
+
+    /**
+     * Subtracts this period from the specified temporal object.
+     * <p>
+     * This returns a temporal object of the same observable type as the input
+     * with this period subtracted.
+     * <p>
+     * In most cases, it is clearer to reverse the calling pattern by using
+     * {@link Temporal#minus(TemporalAmount)}.
+     * <pre>
+     *   // these two lines are equivalent, but the second approach is recommended
+     *   dateTime = thisPeriod.subtractFrom(dateTime);
+     *   dateTime = dateTime.minus(thisPeriod);
+     * </pre>
+     * <p>
+     * The specified temporal must have the same chronology as this period.
+     * This returns a temporal with the non-zero supported units subtracted.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param temporal  the temporal object to adjust, not null
+     * @return an object of the same type with the adjustment made, not null
+     * @throws DateTimeException if unable to subtract
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    @Override
+    Temporal subtractFrom(Temporal temporal);
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if this period is equal to another period, including the chronology.
+     * <p>
+     * Compares this period with another ensuring that the type, each amount and
+     * the chronology are the same.
+     * Note that this means that a period of "15 Months" is not equal to a period
+     * of "1 Year and 3 Months".
+     *
+     * @param obj  the object to check, null returns false
+     * @return true if this is equal to the other period
+     */
+    @Override
+    boolean equals(Object obj);
+
+    /**
+     * A hash code for this period.
+     *
+     * @return a suitable hash code
+     */
+    @Override
+    int hashCode();
+
+    //-----------------------------------------------------------------------
+    /**
+     * Outputs this period as a {@code String}.
+     * <p>
+     * The output will include the period amounts and chronology.
+     *
+     * @return a string representation of this period, not null
+     */
+    @Override
+    String toString();
+
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/time/chrono/ChronoPeriodImpl.java	Wed Sep 04 15:18:54 2013 +0100
@@ -0,0 +1,399 @@
+/*
+ * Copyright (c) 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.
+ */
+
+/*
+ * Copyright (c) 2013, 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.chrono;
+
+import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
+import static java.time.temporal.ChronoUnit.DAYS;
+import static java.time.temporal.ChronoUnit.MONTHS;
+import static java.time.temporal.ChronoUnit.YEARS;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.io.InvalidObjectException;
+import java.io.ObjectStreamException;
+import java.io.Serializable;
+import java.time.DateTimeException;
+import java.time.temporal.ChronoUnit;
+import java.time.temporal.Temporal;
+import java.time.temporal.TemporalAccessor;
+import java.time.temporal.TemporalAmount;
+import java.time.temporal.TemporalQuery;
+import java.time.temporal.TemporalUnit;
+import java.time.temporal.UnsupportedTemporalTypeException;
+import java.time.temporal.ValueRange;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * A period expressed in terms of a standard year-month-day calendar system.
+ * <p>
+ * This class is used by applications seeking to handle dates in non-ISO calendar systems.
+ * For example, the Japanese, Minguo, Thai Buddhist and others.
+ *
+ * @implSpec
+ * This class is immutable nad thread-safe.
+ *
+ * @since 1.8
+ */
+final class ChronoPeriodImpl
+        implements ChronoPeriod, Serializable {
+    // this class is only used by JDK chronology implementations and makes assumptions based on that fact
+
+    /**
+     * Serialization version.
+     */
+    private static final long serialVersionUID = 57387258289L;
+
+    /**
+     * The set of supported units.
+     */
+    private final static List<TemporalUnit> SUPPORTED_UNITS =
+            Collections.unmodifiableList(Arrays.<TemporalUnit>asList(YEARS, MONTHS, DAYS));
+
+    /**
+     * The chronology.
+     */
+    private final Chronology chrono;
+    /**
+     * The number of years.
+     */
+    final int years;
+    /**
+     * The number of months.
+     */
+    final int months;
+    /**
+     * The number of days.
+     */
+    final int days;
+
+    /**
+     * Creates an instance.
+     */
+    ChronoPeriodImpl(Chronology chrono, int years, int months, int days) {
+        Objects.requireNonNull(chrono, "chrono");
+        this.chrono = chrono;
+        this.years = years;
+        this.months = months;
+        this.days = days;
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public long get(TemporalUnit unit) {
+        if (unit == ChronoUnit.YEARS) {
+            return years;
+        } else if (unit == ChronoUnit.MONTHS) {
+            return months;
+        } else if (unit == ChronoUnit.DAYS) {
+            return days;
+        } else {
+            throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
+        }
+    }
+
+    @Override
+    public List<TemporalUnit> getUnits() {
+        return ChronoPeriodImpl.SUPPORTED_UNITS;
+    }
+
+    @Override
+    public Chronology getChronology() {
+        return chrono;
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public boolean isZero() {
+        return years == 0 && months == 0 && days == 0;
+    }
+
+    @Override
+    public boolean isNegative() {
+        return years < 0 || months < 0 || days < 0;
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public ChronoPeriod plus(TemporalAmount amountToAdd) {
+        ChronoPeriodImpl amount = validateAmount(amountToAdd);
+        return new ChronoPeriodImpl(
+                chrono,
+                Math.addExact(years, amount.years),
+                Math.addExact(months, amount.months),
+                Math.addExact(days, amount.days));
+    }
+
+    @Override
+    public ChronoPeriod minus(TemporalAmount amountToSubtract) {
+        ChronoPeriodImpl amount = validateAmount(amountToSubtract);
+        return new ChronoPeriodImpl(
+                chrono,
+                Math.subtractExact(years, amount.years),
+                Math.subtractExact(months, amount.months),
+                Math.subtractExact(days, amount.days));
+    }
+
+    /**
+     * Obtains an instance of {@code ChronoPeriodImpl} from a temporal amount.
+     *
+     * @param amount  the temporal amount to convert, not null
+     * @return the period, not null
+     */
+    private ChronoPeriodImpl validateAmount(TemporalAmount amount) {
+        Objects.requireNonNull(amount, "amount");
+        if (amount instanceof ChronoPeriodImpl == false) {
+            throw new DateTimeException("Unable to obtain ChronoPeriod from TemporalAmount: " + amount.getClass());
+        }
+        ChronoPeriodImpl period = (ChronoPeriodImpl) amount;
+        if (chrono.equals(period.getChronology()) == false) {
+            throw new ClassCastException("Chronology mismatch, expected: " + chrono.getId() + ", actual: " + period.getChronology().getId());
+        }
+        return period;
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public ChronoPeriod multipliedBy(int scalar) {
+        if (this.isZero() || scalar == 1) {
+            return this;
+        }
+        return new ChronoPeriodImpl(
+                chrono,
+                Math.multiplyExact(years, scalar),
+                Math.multiplyExact(months, scalar),
+                Math.multiplyExact(days, scalar));
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public ChronoPeriod normalized() {
+        long monthRange = monthRange();
+        if (monthRange > 0) {
+            long totalMonths = years * monthRange + months;
+            long splitYears = totalMonths / monthRange;
+            int splitMonths = (int) (totalMonths % monthRange);  // no overflow
+            if (splitYears == years && splitMonths == months) {
+                return this;
+            }
+            return new ChronoPeriodImpl(chrono, Math.toIntExact(splitYears), splitMonths, days);
+
+        }
+        return this;
+    }
+
+    /**
+     * Calculates the range of months.
+     *
+     * @return the month range, -1 if not fixed range
+     */
+    private long monthRange() {
+        ValueRange startRange = chrono.range(MONTH_OF_YEAR);
+        if (startRange.isFixed() && startRange.isIntValue()) {
+            return startRange.getMaximum() - startRange.getMinimum() + 1;
+        }
+        return -1;
+    }
+
+    //-------------------------------------------------------------------------
+    @Override
+    public Temporal addTo(Temporal temporal) {
+        validateChrono(temporal);
+        if (months == 0) {
+            if (years != 0) {
+                temporal = temporal.plus(years, YEARS);
+            }
+        } else {
+            long monthRange = monthRange();
+            if (monthRange > 0) {
+                temporal = temporal.plus(years * monthRange + months, MONTHS);
+            } else {
+                if (years != 0) {
+                    temporal = temporal.plus(years, YEARS);
+                }
+                temporal = temporal.plus(months, MONTHS);
+            }
+        }
+        if (days != 0) {
+            temporal = temporal.plus(days, DAYS);
+        }
+        return temporal;
+    }
+
+
+
+    @Override
+    public Temporal subtractFrom(Temporal temporal) {
+        validateChrono(temporal);
+        if (months == 0) {
+            if (years != 0) {
+                temporal = temporal.minus(years, YEARS);
+            }
+        } else {
+            long monthRange = monthRange();
+            if (monthRange > 0) {
+                temporal = temporal.minus(years * monthRange + months, MONTHS);
+            } else {
+                if (years != 0) {
+                    temporal = temporal.minus(years, YEARS);
+                }
+                temporal = temporal.minus(months, MONTHS);
+            }
+        }
+        if (days != 0) {
+            temporal = temporal.minus(days, DAYS);
+        }
+        return temporal;
+    }
+
+    /**
+     * Validates that the temporal has the correct chronology.
+     */
+    private void validateChrono(TemporalAccessor temporal) {
+        Objects.requireNonNull(temporal, "temporal");
+        Chronology temporalChrono = temporal.query(TemporalQuery.chronology());
+        if (temporalChrono != null && chrono.equals(temporalChrono) == false) {
+            throw new DateTimeException("Chronology mismatch, expected: " + chrono.getId() + ", actual: " + temporalChrono.getId());
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof ChronoPeriodImpl) {
+            ChronoPeriodImpl other = (ChronoPeriodImpl) obj;
+            return years == other.years && months == other.months &&
+                    days == other.days && chrono.equals(other.chrono);
+        }
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return (years + Integer.rotateLeft(months, 8) + Integer.rotateLeft(days, 16)) ^ chrono.hashCode();
+    }
+
+    //-----------------------------------------------------------------------
+    @Override
+    public String toString() {
+        if (isZero()) {
+            return getChronology().toString() + " P0D";
+        } else {
+            StringBuilder buf = new StringBuilder();
+            buf.append(getChronology().toString()).append(' ').append('P');
+            if (years != 0) {
+                buf.append(years).append('Y');
+            }
+            if (months != 0) {
+                buf.append(months).append('M');
+            }
+            if (days != 0) {
+                buf.append(days).append('D');
+            }
+            return buf.toString();
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Writes the Chronology using a
+     * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
+     * <pre>
+     *  out.writeByte(12);  // identifies this as a ChronoPeriodImpl
+     *  out.writeUTF(getId());  // the chronology
+     *  out.writeInt(years);
+     *  out.writeInt(months);
+     *  out.writeInt(days);
+     * </pre>
+     *
+     * @return the instance of {@code Ser}, not null
+     */
+    protected Object writeReplace() {
+        return new Ser(Ser.CHRONO_PERIOD_TYPE, this);
+    }
+
+    /**
+     * Defend against malicious streams.
+     * @return never
+     * @throws InvalidObjectException always
+     */
+    private Object readResolve() throws ObjectStreamException {
+        throw new InvalidObjectException("Deserialization via serialization delegate");
+    }
+
+    void writeExternal(DataOutput out) throws IOException {
+        out.writeUTF(chrono.getId());
+        out.writeInt(years);
+        out.writeInt(months);
+        out.writeInt(days);
+    }
+
+    static ChronoPeriodImpl readExternal(DataInput in) throws IOException {
+        Chronology chrono = Chronology.of(in.readUTF());
+        int years = in.readInt();
+        int months = in.readInt();
+        int days = in.readInt();
+        return new ChronoPeriodImpl(chrono, years, months, days);
+    }
+
+}
--- a/jdk/src/share/classes/java/time/chrono/Chronology.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/Chronology.java	Wed Sep 04 15:18:54 2013 +0100
@@ -91,14 +91,11 @@
 import java.time.Instant;
 import java.time.LocalDate;
 import java.time.LocalTime;
-import java.time.Month;
-import java.time.Year;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatterBuilder;
 import java.time.format.ResolverStyle;
 import java.time.format.TextStyle;
 import java.time.temporal.ChronoField;
-import java.time.temporal.Temporal;
 import java.time.temporal.TemporalAccessor;
 import java.time.temporal.TemporalAdjuster;
 import java.time.temporal.TemporalField;
@@ -1192,6 +1189,38 @@
 
     //-----------------------------------------------------------------------
     /**
+     * Obtains a period for this chronology based on years, months and days.
+     * <p>
+     * This returns a period tied to this chronology using the specified
+     * years, months and days.  All supplied chronologies use periods
+     * based on years, months and days, however the {@code ChronoPeriod} API
+     * allows the period to be represented using other units.
+     *
+     * @implSpec
+     * The default implementation returns an implementation class suitable
+     * for most calendar systems. It is based solely on the three units.
+     * Normalization, addition and subtraction derive the number of months
+     * in a year from the {@link #range(ChronoField)}. If the number of
+     * months within a year is fixed, then the calculation approach for
+     * addition, subtraction and normalization is slightly different.
+     * <p>
+     * If implementing an unusual calendar system that is not based on
+     * years, months and days, or where you want direct control, then
+     * the {@code ChronoPeriod} interface must be directly implemented.
+     * <p>
+     * The returned period is immutable and thread-safe.
+     *
+     * @param years  the number of years, may be negative
+     * @param months  the number of years, may be negative
+     * @param days  the number of years, may be negative
+     * @return the period in terms of this chronology, not null
+     */
+    public ChronoPeriod period(int years, int months, int days) {
+        return new ChronoPeriodImpl(this, years, months, days);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
      * Compares this chronology to another chronology.
      * <p>
      * The comparison order first by the chronology ID string, then by any
--- a/jdk/src/share/classes/java/time/chrono/HijrahDate.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/HijrahDate.java	Wed Sep 04 15:18:54 2013 +0100
@@ -73,7 +73,6 @@
 import java.time.DateTimeException;
 import java.time.LocalDate;
 import java.time.LocalTime;
-import java.time.Period;
 import java.time.ZoneId;
 import java.time.temporal.ChronoField;
 import java.time.temporal.TemporalAccessor;
@@ -582,7 +581,7 @@
     }
 
     @Override
-    public Period until(ChronoLocalDate endDate) {
+    public ChronoPeriod until(ChronoLocalDate endDate) {
         // TODO: untested
         HijrahDate end = getChronology().date(endDate);
         long totalMonths = (end.prolepticYear - this.prolepticYear) * 12 + (end.monthOfYear - this.monthOfYear);  // safe
@@ -597,7 +596,7 @@
         }
         long years = totalMonths / 12;  // safe
         int months = (int) (totalMonths % 12);  // safe
-        return Period.of(Math.toIntExact(years), months, days);
+        return getChronology().period(Math.toIntExact(years), months, days);
     }
 
     //-----------------------------------------------------------------------
--- a/jdk/src/share/classes/java/time/chrono/IsoChronology.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/IsoChronology.java	Wed Sep 04 15:18:54 2013 +0100
@@ -77,6 +77,7 @@
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.Month;
+import java.time.Period;
 import java.time.Year;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
@@ -567,6 +568,24 @@
 
     //-----------------------------------------------------------------------
     /**
+     * Obtains a period for this chronology based on years, months and days.
+     * <p>
+     * This returns a period tied to the ISO chronology using the specified
+     * years, months and days. See {@link Period} for further details.
+     *
+     * @param years  the number of years, may be negative
+     * @param months  the number of years, may be negative
+     * @param days  the number of years, may be negative
+     * @return the period in terms of this chronology, not null
+     * @return the ISO period, not null
+     */
+    @Override  // override with covariant return type
+    public Period period(int years, int months, int days) {
+        return Period.of(years, months, days);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
      * Writes the Chronology using a
      * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
      * @serialData
--- a/jdk/src/share/classes/java/time/chrono/JapaneseDate.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/JapaneseDate.java	Wed Sep 04 15:18:54 2013 +0100
@@ -659,8 +659,9 @@
     }
 
     @Override
-    public Period until(ChronoLocalDate endDate) {
-        return isoDate.until(endDate);
+    public ChronoPeriod until(ChronoLocalDate endDate) {
+        Period period = isoDate.until(endDate);
+        return getChronology().period(period.getYears(), period.getMonths(), period.getDays());
     }
 
     @Override  // override for performance
--- a/jdk/src/share/classes/java/time/chrono/MinguoDate.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/MinguoDate.java	Wed Sep 04 15:18:54 2013 +0100
@@ -421,8 +421,9 @@
     }
 
     @Override
-    public Period until(ChronoLocalDate endDate) {
-        return isoDate.until(endDate);
+    public ChronoPeriod until(ChronoLocalDate endDate) {
+        Period period = isoDate.until(endDate);
+        return getChronology().period(period.getYears(), period.getMonths(), period.getDays());
     }
 
     @Override  // override for performance
--- a/jdk/src/share/classes/java/time/chrono/Ser.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/Ser.java	Wed Sep 04 15:18:54 2013 +0100
@@ -104,6 +104,7 @@
     static final byte HIJRAH_DATE_TYPE = 6;
     static final byte MINGUO_DATE_TYPE = 7;
     static final byte THAIBUDDHIST_DATE_TYPE = 8;
+    static final byte CHRONO_PERIOD_TYPE = 9;
 
     /** The type being serialized. */
     private byte type;
@@ -183,6 +184,9 @@
             case THAIBUDDHIST_DATE_TYPE:
                 ((ThaiBuddhistDate) object).writeExternal(out);
                 break;
+            case CHRONO_PERIOD_TYPE:
+                ((ChronoPeriodImpl) object).writeExternal(out);
+                break;
             default:
                 throw new InvalidClassException("Unknown serialized type");
         }
@@ -235,6 +239,7 @@
             case HIJRAH_DATE_TYPE: return HijrahDate.readExternal(in);
             case MINGUO_DATE_TYPE: return MinguoDate.readExternal(in);
             case THAIBUDDHIST_DATE_TYPE: return ThaiBuddhistDate.readExternal(in);
+            case CHRONO_PERIOD_TYPE: return ChronoPeriodImpl.readExternal(in);
             default: throw new StreamCorruptedException("Unknown serialized type");
         }
     }
--- a/jdk/src/share/classes/java/time/chrono/ThaiBuddhistDate.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/chrono/ThaiBuddhistDate.java	Wed Sep 04 15:18:54 2013 +0100
@@ -421,8 +421,9 @@
     }
 
     @Override
-    public Period until(ChronoLocalDate endDate) {
-        return isoDate.until(endDate);
+    public ChronoPeriod until(ChronoLocalDate endDate) {
+        Period period = isoDate.until(endDate);
+        return getChronology().period(period.getYears(), period.getMonths(), period.getDays());
     }
 
     @Override  // override for performance
--- a/jdk/src/share/classes/java/time/temporal/Temporal.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/src/share/classes/java/time/temporal/Temporal.java	Wed Sep 04 15:18:54 2013 +0100
@@ -170,7 +170,8 @@
      * </pre>
      *
      * @implSpec
-     * Implementations must not alter either this object.
+     * <p>
+     * Implementations must not alter either this object or the specified temporal object.
      * Instead, an adjusted copy of the original must be returned.
      * This provides equivalent, safe behavior for immutable and mutable implementations.
      * <p>
@@ -209,7 +210,7 @@
      * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
      * passing {@code this} as the first argument.
      * <p>
-     * Implementations must not alter either this object or the specified temporal object.
+     * Implementations must not alter this object.
      * Instead, an adjusted copy of the original must be returned.
      * This provides equivalent, safe behavior for immutable and mutable implementations.
      *
@@ -232,16 +233,17 @@
      * <p>
      * Some example code indicating how and why this method is used:
      * <pre>
-     *  date = date.plus(period);                      // add a Period instance
-     *  date = date.plus(duration);                    // add a Duration instance
-     *  date = date.plus(workingDays(6));              // example user-written workingDays method
+     *  date = date.plus(period);                // add a Period instance
+     *  date = date.plus(duration);              // add a Duration instance
+     *  date = date.plus(workingDays(6));        // example user-written workingDays method
      * </pre>
      * <p>
      * Note that calling {@code plus} followed by {@code minus} is not guaranteed to
      * return the same date-time.
      *
      * @implSpec
-     * Implementations must not alter either this object.
+     * <p>
+     * Implementations must not alter either this object or the specified temporal object.
      * Instead, an adjusted copy of the original must be returned.
      * This provides equivalent, safe behavior for immutable and mutable implementations.
      * <p>
@@ -280,7 +282,7 @@
      * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
      * passing {@code this} as the first argument.
      * <p>
-     * Implementations must not alter either this object or the specified temporal object.
+     * Implementations must not alter this object.
      * Instead, an adjusted copy of the original must be returned.
      * This provides equivalent, safe behavior for immutable and mutable implementations.
      *
@@ -303,16 +305,17 @@
      * <p>
      * Some example code indicating how and why this method is used:
      * <pre>
-     *  date = date.minus(period);                      // subtract a Period instance
-     *  date = date.minus(duration);                    // subtract a Duration instance
-     *  date = date.minus(workingDays(6));              // example user-written workingDays method
+     *  date = date.minus(period);               // subtract a Period instance
+     *  date = date.minus(duration);             // subtract a Duration instance
+     *  date = date.minus(workingDays(6));       // example user-written workingDays method
      * </pre>
      * <p>
      * Note that calling {@code plus} followed by {@code minus} is not guaranteed to
      * return the same date-time.
      *
      * @implSpec
-     * Implementations must not alter either this object.
+     * <p>
+     * Implementations must not alter either this object or the specified temporal object.
      * Instead, an adjusted copy of the original must be returned.
      * This provides equivalent, safe behavior for immutable and mutable implementations.
      * <p>
@@ -345,7 +348,7 @@
      * @implSpec
      * Implementations must behave in a manor equivalent to the default method behavior.
      * <p>
-     * Implementations must not alter either this object or the specified temporal object.
+     * Implementations must not alter this object.
      * Instead, an adjusted copy of the original must be returned.
      * This provides equivalent, safe behavior for immutable and mutable implementations.
      * <p>
--- a/jdk/test/java/time/tck/java/time/TCKPeriod.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/test/java/time/tck/java/time/TCKPeriod.java	Wed Sep 04 15:18:54 2013 +0100
@@ -60,6 +60,7 @@
 package tck.java.time;
 
 import static java.time.temporal.ChronoUnit.DAYS;
+import static java.time.temporal.ChronoUnit.HOURS;
 import static java.time.temporal.ChronoUnit.YEARS;
 import static org.testng.Assert.assertEquals;
 
@@ -67,6 +68,7 @@
 import java.time.Duration;
 import java.time.LocalDate;
 import java.time.Period;
+import java.time.chrono.ThaiBuddhistChronology;
 import java.time.format.DateTimeParseException;
 import java.time.temporal.ChronoUnit;
 import java.time.temporal.Temporal;
@@ -213,6 +215,41 @@
     }
 
     @Test(expectedExceptions = DateTimeException.class)
+    public void factory_from_TemporalAmount_DaysHours() {
+        TemporalAmount amount = new TemporalAmount() {
+            @Override
+            public long get(TemporalUnit unit) {
+                if (unit == DAYS) {
+                    return 1;
+                } else {
+                    return 2;
+                }
+            }
+            @Override
+            public List<TemporalUnit> getUnits() {
+                List<TemporalUnit> list = new ArrayList<>();
+                list.add(DAYS);
+                list.add(HOURS);
+                return list;
+            }
+            @Override
+            public Temporal addTo(Temporal temporal) {
+                throw new UnsupportedOperationException();
+            }
+            @Override
+            public Temporal subtractFrom(Temporal temporal) {
+                throw new UnsupportedOperationException();
+            }
+        };
+        Period.from(amount);
+    }
+
+    @Test(expectedExceptions = DateTimeException.class)
+    public void factory_from_TemporalAmount_NonISO() {
+        Period.from(ThaiBuddhistChronology.INSTANCE.period(1, 1, 1));
+    }
+
+    @Test(expectedExceptions = DateTimeException.class)
     public void factory_from_TemporalAmount_Duration() {
         Period.from(Duration.ZERO);
     }
@@ -594,10 +631,45 @@
     }
 
     @Test(dataProvider="plus")
-    public void test_plus(Period base, Period add, Period expected) {
+    public void test_plus_TemporalAmount(Period base, Period add, Period expected) {
         assertEquals(base.plus(add), expected);
     }
 
+    @Test(expectedExceptions = DateTimeException.class)
+    public void test_plus_TemporalAmount_nonISO() {
+        pymd(4, 5, 6).plus(ThaiBuddhistChronology.INSTANCE.period(1, 0, 0));
+    }
+
+    @Test(expectedExceptions = DateTimeException.class)
+    public void test_plus_TemporalAmount_DaysHours() {
+        TemporalAmount amount = new TemporalAmount() {
+            @Override
+            public long get(TemporalUnit unit) {
+                if (unit == DAYS) {
+                    return 1;
+                } else {
+                    return 2;
+                }
+            }
+            @Override
+            public List<TemporalUnit> getUnits() {
+                List<TemporalUnit> list = new ArrayList<>();
+                list.add(DAYS);
+                list.add(HOURS);
+                return list;
+            }
+            @Override
+            public Temporal addTo(Temporal temporal) {
+                throw new UnsupportedOperationException();
+            }
+            @Override
+            public Temporal subtractFrom(Temporal temporal) {
+                throw new UnsupportedOperationException();
+            }
+        };
+        pymd(4, 5, 6).plus(amount);
+    }
+
     //-----------------------------------------------------------------------
     // plusYears()
     //-----------------------------------------------------------------------
@@ -704,10 +776,45 @@
     }
 
     @Test(dataProvider="minus")
-    public void test_minus(Period base, Period subtract, Period expected) {
+    public void test_minus_TemporalAmount(Period base, Period subtract, Period expected) {
         assertEquals(base.minus(subtract), expected);
     }
 
+    @Test(expectedExceptions = DateTimeException.class)
+    public void test_minus_TemporalAmount_nonISO() {
+        pymd(4, 5, 6).minus(ThaiBuddhistChronology.INSTANCE.period(1, 0, 0));
+    }
+
+    @Test(expectedExceptions = DateTimeException.class)
+    public void test_minus_TemporalAmount_DaysHours() {
+        TemporalAmount amount = new TemporalAmount() {
+            @Override
+            public long get(TemporalUnit unit) {
+                if (unit == DAYS) {
+                    return 1;
+                } else {
+                    return 2;
+                }
+            }
+            @Override
+            public List<TemporalUnit> getUnits() {
+                List<TemporalUnit> list = new ArrayList<>();
+                list.add(DAYS);
+                list.add(HOURS);
+                return list;
+            }
+            @Override
+            public Temporal addTo(Temporal temporal) {
+                throw new UnsupportedOperationException();
+            }
+            @Override
+            public Temporal subtractFrom(Temporal temporal) {
+                throw new UnsupportedOperationException();
+            }
+        };
+        pymd(4, 5, 6).minus(amount);
+    }
+
     //-----------------------------------------------------------------------
     // minusYears()
     //-----------------------------------------------------------------------
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/time/tck/java/time/chrono/TCKChronoPeriod.java	Wed Sep 04 15:18:54 2013 +0100
@@ -0,0 +1,279 @@
+/*
+ * Copyright (c) 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.
+ */
+
+/*
+ * Copyright (c) 2013, 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 tck.java.time.chrono;
+
+import static java.time.temporal.ChronoUnit.DAYS;
+import static java.time.temporal.ChronoUnit.HOURS;
+import static java.time.temporal.ChronoUnit.MONTHS;
+import static java.time.temporal.ChronoUnit.YEARS;
+import static org.testng.Assert.assertEquals;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.time.DateTimeException;
+import java.time.LocalDate;
+import java.time.Period;
+import java.time.chrono.ChronoLocalDate;
+import java.time.chrono.ChronoPeriod;
+import java.time.chrono.Chronology;
+import java.time.chrono.HijrahChronology;
+import java.time.chrono.IsoChronology;
+import java.time.chrono.JapaneseChronology;
+import java.time.chrono.MinguoChronology;
+import java.time.chrono.ThaiBuddhistChronology;
+import java.time.temporal.Temporal;
+import java.time.temporal.UnsupportedTemporalTypeException;
+
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+public class TCKChronoPeriod {
+
+    //-----------------------------------------------------------------------
+    // regular data factory for names and descriptions of available calendars
+    //-----------------------------------------------------------------------
+    @DataProvider(name = "calendars")
+    Chronology[][] data_of_calendars() {
+        return new Chronology[][]{
+                    {HijrahChronology.INSTANCE},
+                    {IsoChronology.INSTANCE},
+                    {JapaneseChronology.INSTANCE},
+                    {MinguoChronology.INSTANCE},
+                    {ThaiBuddhistChronology.INSTANCE}};
+    }
+
+    //-----------------------------------------------------------------------
+    // Test Serialization of Calendars
+    //-----------------------------------------------------------------------
+    @Test(dataProvider="calendars")
+    public void test_serialization(Chronology chrono) throws Exception {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ObjectOutputStream out = new ObjectOutputStream(baos);
+        out.writeObject(period);
+        out.close();
+        ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+
+        ObjectInputStream in = new ObjectInputStream(bais);
+        ChronoPeriod ser = (ChronoPeriod) in.readObject();
+        assertEquals(ser, period, "deserialized ChronoPeriod is wrong");
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_get(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        assertEquals(period.get(YEARS), 1);
+        assertEquals(period.get(MONTHS), 2);
+        assertEquals(period.get(DAYS), 3);
+    }
+
+    @Test(dataProvider="calendars", expectedExceptions=UnsupportedTemporalTypeException.class)
+    public void test_get_unsupported(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        period.get(HOURS);
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_getUnits(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        assertEquals(period.getUnits().size(), 3);
+        assertEquals(period.getUnits().get(0), YEARS);
+        assertEquals(period.getUnits().get(1), MONTHS);
+        assertEquals(period.getUnits().get(2), DAYS);
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_getChronology(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        assertEquals(period.getChronology(), chrono);
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_isZero_isNegative(Chronology chrono) {
+        ChronoPeriod periodPositive = chrono.period(1, 2, 3);
+        assertEquals(periodPositive.isZero(), false);
+        assertEquals(periodPositive.isNegative(), false);
+
+        ChronoPeriod periodZero = chrono.period(0, 0, 0);
+        assertEquals(periodZero.isZero(), true);
+        assertEquals(periodZero.isNegative(), false);
+
+        ChronoPeriod periodNegative = chrono.period(-1, 0, 0);
+        assertEquals(periodNegative.isZero(), false);
+        assertEquals(periodNegative.isNegative(), true);
+    }
+
+    //-----------------------------------------------------------------------
+    @Test(dataProvider="calendars")
+    public void test_plus(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoPeriod period2 = chrono.period(2, 3, 4);
+        ChronoPeriod result = period.plus(period2);
+        assertEquals(result, chrono.period(3, 5, 7));
+    }
+
+    @Test(dataProvider="calendars", expectedExceptions=DateTimeException.class)
+    public void test_plus_wrongChrono(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoPeriod isoPeriod = Period.of(2, 3, 4);
+        ChronoPeriod thaiPeriod = ThaiBuddhistChronology.INSTANCE.period(2, 3, 4);
+        // one of these two will fail
+        period.plus(isoPeriod);
+        period.plus(thaiPeriod);
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_minus(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoPeriod period2 = chrono.period(2, 3, 4);
+        ChronoPeriod result = period.minus(period2);
+        assertEquals(result, chrono.period(-1, -1, -1));
+    }
+
+    @Test(dataProvider="calendars", expectedExceptions=DateTimeException.class)
+    public void test_minus_wrongChrono(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoPeriod isoPeriod = Period.of(2, 3, 4);
+        ChronoPeriod thaiPeriod = ThaiBuddhistChronology.INSTANCE.period(2, 3, 4);
+        // one of these two will fail
+        period.minus(isoPeriod);
+        period.minus(thaiPeriod);
+    }
+
+    //-----------------------------------------------------------------------
+    @Test(dataProvider="calendars")
+    public void test_addTo(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoLocalDate date = chrono.dateNow();
+        Temporal result = period.addTo(date);
+        assertEquals(result, date.plus(14, MONTHS).plus(3, DAYS));
+    }
+
+    @Test(dataProvider="calendars", expectedExceptions=DateTimeException.class)
+    public void test_addTo_wrongChrono(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoLocalDate isoDate = LocalDate.of(2000, 1, 1);
+        ChronoLocalDate thaiDate = ThaiBuddhistChronology.INSTANCE.date(2000, 1, 1);
+        // one of these two will fail
+        period.addTo(isoDate);
+        period.addTo(thaiDate);
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_subtractFrom(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoLocalDate date = chrono.dateNow();
+        Temporal result = period.subtractFrom(date);
+        assertEquals(result, date.minus(14, MONTHS).minus(3, DAYS));
+    }
+
+    @Test(dataProvider="calendars", expectedExceptions=DateTimeException.class)
+    public void test_subtractFrom_wrongChrono(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        ChronoLocalDate isoDate = LocalDate.of(2000, 1, 1);
+        ChronoLocalDate thaiDate = ThaiBuddhistChronology.INSTANCE.date(2000, 1, 1);
+        // one of these two will fail
+        period.subtractFrom(isoDate);
+        period.subtractFrom(thaiDate);
+    }
+
+    //-----------------------------------------------------------------------
+    @Test(dataProvider="calendars")
+    public void test_negated(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        assertEquals(period.negated(), chrono.period(-1, -2, -3));
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_multipliedBy(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        assertEquals(period.multipliedBy(3), chrono.period(3, 6, 9));
+    }
+
+    //-----------------------------------------------------------------------
+    @Test(dataProvider="calendars")
+    public void test_equals_equal(Chronology chrono) {
+        ChronoPeriod a1 = chrono.period(1, 2, 3);
+        ChronoPeriod a2 = chrono.period(1, 2, 3);
+        assertEquals(a1, a1);
+        assertEquals(a1, a2);
+        assertEquals(a2, a1);
+        assertEquals(a2, a2);
+        assertEquals(a1.hashCode(), a2.hashCode());
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_equals_notEqual(Chronology chrono) {
+        ChronoPeriod a = chrono.period(1, 2, 3);
+        ChronoPeriod b = chrono.period(2, 2, 3);
+        assertEquals(a.equals(b), false);
+        assertEquals(b.equals(a), false);
+        assertEquals(a.equals(""), false);
+        assertEquals(a.equals(null), false);
+    }
+
+    @Test(dataProvider="calendars")
+    public void test_toString(Chronology chrono) {
+        ChronoPeriod period = chrono.period(1, 2, 3);
+        if (period instanceof Period == false) {
+            assertEquals(period.toString(), chrono.getId() + " P1Y2M3D");
+        }
+    }
+
+}
--- a/jdk/test/java/time/tck/java/time/chrono/TCKJapaneseChronology.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/test/java/time/tck/java/time/chrono/TCKJapaneseChronology.java	Wed Sep 04 15:18:54 2013 +0100
@@ -79,6 +79,7 @@
 import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.chrono.ChronoLocalDate;
+import java.time.chrono.ChronoPeriod;
 import java.time.chrono.Chronology;
 import java.time.chrono.Era;
 import java.time.chrono.IsoChronology;
@@ -87,6 +88,7 @@
 import java.time.chrono.JapaneseEra;
 import java.time.chrono.MinguoChronology;
 import java.time.chrono.MinguoDate;
+import java.time.chrono.ThaiBuddhistChronology;
 import java.time.format.ResolverStyle;
 import java.time.temporal.ChronoField;
 import java.time.temporal.ChronoUnit;
@@ -615,8 +617,8 @@
     public void test_periodUntilDate() {
         JapaneseDate mdate1 = JapaneseDate.of(1970, 1, 1);
         JapaneseDate mdate2 = JapaneseDate.of(1971, 2, 2);
-        Period period = mdate1.until(mdate2);
-        assertEquals(period, Period.of(1, 1, 1));
+        ChronoPeriod period = mdate1.until(mdate2);
+        assertEquals(period, JapaneseChronology.INSTANCE.period(1, 1, 1));
     }
 
     @Test
@@ -632,8 +634,8 @@
         JapaneseDate mdate1 = JapaneseDate.of(1970, 1, 1);
         JapaneseDate mdate2 = JapaneseDate.of(1971, 2, 2);
         MinguoDate ldate2 = MinguoChronology.INSTANCE.date(mdate2);
-        Period period = mdate1.until(ldate2);
-        assertEquals(period, Period.of(1, 1, 1));
+        ChronoPeriod period = mdate1.until(ldate2);
+        assertEquals(period, JapaneseChronology.INSTANCE.period(1, 1, 1));
     }
 
     //-----------------------------------------------------------------------
--- a/jdk/test/java/time/tck/java/time/chrono/TCKMinguoChronology.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/test/java/time/tck/java/time/chrono/TCKMinguoChronology.java	Wed Sep 04 15:18:54 2013 +0100
@@ -69,13 +69,13 @@
 import java.time.LocalTime;
 import java.time.Month;
 import java.time.OffsetDateTime;
-import java.time.Period;
 import java.time.Year;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.time.chrono.ChronoLocalDate;
 import java.time.chrono.ChronoLocalDateTime;
+import java.time.chrono.ChronoPeriod;
 import java.time.chrono.ChronoZonedDateTime;
 import java.time.chrono.Chronology;
 import java.time.chrono.Era;
@@ -84,8 +84,6 @@
 import java.time.chrono.MinguoChronology;
 import java.time.chrono.MinguoDate;
 import java.time.chrono.MinguoEra;
-import java.time.chrono.MinguoChronology;
-import java.time.chrono.MinguoDate;
 import java.time.chrono.ThaiBuddhistChronology;
 import java.time.chrono.ThaiBuddhistDate;
 import java.time.format.ResolverStyle;
@@ -499,8 +497,8 @@
     public void test_periodUntilDate() {
         MinguoDate mdate1 = MinguoDate.of(1970, 1, 1);
         MinguoDate mdate2 = MinguoDate.of(1971, 2, 2);
-        Period period = mdate1.until(mdate2);
-        assertEquals(period, Period.of(1, 1, 1));
+        ChronoPeriod period = mdate1.until(mdate2);
+        assertEquals(period, MinguoChronology.INSTANCE.period(1, 1, 1));
     }
 
     @Test
@@ -516,8 +514,8 @@
         MinguoDate mdate1 = MinguoDate.of(1970, 1, 1);
         MinguoDate mdate2 = MinguoDate.of(1971, 2, 2);
         ThaiBuddhistDate ldate2 = ThaiBuddhistChronology.INSTANCE.date(mdate2);
-        Period period = mdate1.until(ldate2);
-        assertEquals(period, Period.of(1, 1, 1));
+        ChronoPeriod period = mdate1.until(ldate2);
+        assertEquals(period, MinguoChronology.INSTANCE.period(1, 1, 1));
     }
 
     //-----------------------------------------------------------------------
--- a/jdk/test/java/time/tck/java/time/chrono/TCKThaiBuddhistChronology.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/test/java/time/tck/java/time/chrono/TCKThaiBuddhistChronology.java	Wed Sep 04 15:18:54 2013 +0100
@@ -72,11 +72,11 @@
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.Month;
-import java.time.Period;
 import java.time.Year;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.chrono.ChronoLocalDate;
+import java.time.chrono.ChronoPeriod;
 import java.time.chrono.Chronology;
 import java.time.chrono.Era;
 import java.time.chrono.IsoChronology;
@@ -458,8 +458,8 @@
     public void test_periodUntilDate() {
         ThaiBuddhistDate mdate1 = ThaiBuddhistDate.of(1, 1, 1);
         ThaiBuddhistDate mdate2 = ThaiBuddhistDate.of(2, 2, 2);
-        Period period = mdate1.until(mdate2);
-        assertEquals(period, Period.of(1, 1, 1));
+        ChronoPeriod period = mdate1.until(mdate2);
+        assertEquals(period, ThaiBuddhistChronology.INSTANCE.period(1, 1, 1));
     }
 
     @Test
@@ -475,8 +475,8 @@
         ThaiBuddhistDate mdate1 = ThaiBuddhistDate.of(1, 1, 1);
         ThaiBuddhistDate mdate2 = ThaiBuddhistDate.of(2, 2, 2);
         MinguoDate ldate2 = MinguoChronology.INSTANCE.date(mdate2);
-        Period period = mdate1.until(ldate2);
-        assertEquals(period, Period.of(1, 1, 1));
+        ChronoPeriod period = mdate1.until(ldate2);
+        assertEquals(period, ThaiBuddhistChronology.INSTANCE.period(1, 1, 1));
     }
 
     //-----------------------------------------------------------------------
--- a/jdk/test/java/time/test/java/time/chrono/TestUmmAlQuraChronology.java	Fri Aug 30 11:43:57 2013 +0100
+++ b/jdk/test/java/time/test/java/time/chrono/TestUmmAlQuraChronology.java	Wed Sep 04 15:18:54 2013 +0100
@@ -26,9 +26,9 @@
 package test.java.time.chrono;
 
 import static java.time.temporal.ChronoField.DAY_OF_MONTH;
+import static java.time.temporal.ChronoField.DAY_OF_YEAR;
 import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
 import static java.time.temporal.ChronoField.YEAR;
-import static java.time.temporal.ChronoField.DAY_OF_YEAR;
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;
@@ -39,12 +39,12 @@
 import java.time.LocalDateTime;
 import java.time.LocalTime;
 import java.time.OffsetDateTime;
-import java.time.Period;
 import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.time.chrono.ChronoLocalDate;
 import java.time.chrono.ChronoLocalDateTime;
+import java.time.chrono.ChronoPeriod;
 import java.time.chrono.ChronoZonedDateTime;
 import java.time.chrono.Chronology;
 import java.time.chrono.HijrahChronology;
@@ -330,26 +330,26 @@
     @DataProvider(name="datesForPeriod")
     Object[][] data_Period() {
         return new Object[][] {
-            {HijrahDate.of(1350, 5, 15), HijrahDate.of(1434, 7, 20), Period.of(84, 2, 5)},
-            {HijrahDate.of(1403, 5, 28), HijrahDate.of(1434, 7, 20), Period.of(31, 1, 22)},
-            {HijrahDate.of(1434, 7, 20), HijrahDate.of(1484, 2, 15), Period.of(49, 6, 24)},
-            {HijrahDate.of(1500, 6, 12), HijrahDate.of(1450, 4, 21), Period.of(-50, -1, -20)},
-            {HijrahDate.of(1549, 3, 11), HijrahDate.of(1550, 3, 10), Period.of(0, 11, 28)},
+            {HijrahDate.of(1350, 5, 15), HijrahDate.of(1434, 7, 20), HijrahChronology.INSTANCE.period(84, 2, 5)},
+            {HijrahDate.of(1403, 5, 28), HijrahDate.of(1434, 7, 20), HijrahChronology.INSTANCE.period(31, 1, 22)},
+            {HijrahDate.of(1434, 7, 20), HijrahDate.of(1484, 2, 15), HijrahChronology.INSTANCE.period(49, 6, 24)},
+            {HijrahDate.of(1500, 6, 12), HijrahDate.of(1450, 4, 21), HijrahChronology.INSTANCE.period(-50, -1, -20)},
+            {HijrahDate.of(1549, 3, 11), HijrahDate.of(1550, 3, 10), HijrahChronology.INSTANCE.period(0, 11, 28)},
         };
     }
 
     // Test to get the Period between two given dates
     @Test(dataProvider="datesForPeriod")
-    public void test_until(HijrahDate h1, HijrahDate h2, Period p) {
-        Period period = h1.until(h2);
+    public void test_until(HijrahDate h1, HijrahDate h2, ChronoPeriod p) {
+        ChronoPeriod period = h1.until(h2);
         assertEquals(period, p);
     }
 
     // Test to get the Period between dates in different chronologies
     @Test(dataProvider="datesForPeriod")
-    public void test_periodUntilDiffChrono(HijrahDate h1, HijrahDate h2, Period p) {
+    public void test_periodUntilDiffChrono(HijrahDate h1, HijrahDate h2, ChronoPeriod p) {
         MinguoDate m = MinguoChronology.INSTANCE.date(h2);
-        Period period = h1.until(m);
+        ChronoPeriod period = h1.until(m);
         assertEquals(period, p);
     }