src/java.base/share/classes/java/time/MonthDay.java
changeset 47216 71c04702a3d5
parent 25859 3317bb8137f4
child 49433 b6671a111395
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/time/MonthDay.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,792 @@
+/*
+ * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ *  * Neither the name of JSR-310 nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package java.time;
+
+import static java.time.temporal.ChronoField.DAY_OF_MONTH;
+import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.io.InvalidObjectException;
+import java.io.ObjectInputStream;
+import java.io.Serializable;
+import java.time.chrono.Chronology;
+import java.time.chrono.IsoChronology;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeFormatterBuilder;
+import java.time.format.DateTimeParseException;
+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;
+import java.time.temporal.TemporalQueries;
+import java.time.temporal.TemporalQuery;
+import java.time.temporal.UnsupportedTemporalTypeException;
+import java.time.temporal.ValueRange;
+import java.util.Objects;
+
+/**
+ * A month-day in the ISO-8601 calendar system, such as {@code --12-03}.
+ * <p>
+ * {@code MonthDay} is an immutable date-time object that represents the combination
+ * of a month and day-of-month. Any field that can be derived from a month and day,
+ * such as quarter-of-year, can be obtained.
+ * <p>
+ * This class does not store or represent a year, time or time-zone.
+ * For example, the value "December 3rd" can be stored in a {@code MonthDay}.
+ * <p>
+ * Since a {@code MonthDay} does not possess a year, the leap day of
+ * February 29th is considered valid.
+ * <p>
+ * This class implements {@link TemporalAccessor} rather than {@link Temporal}.
+ * This is because it is not possible to define whether February 29th is valid or not
+ * without external information, preventing the implementation of plus/minus.
+ * Related to this, {@code MonthDay} only provides access to query and set the fields
+ * {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH}.
+ * <p>
+ * 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.
+ * For most applications written today, the ISO-8601 rules are entirely suitable.
+ * However, any application that makes use of historical dates, and requires them
+ * to be accurate will find the ISO-8601 approach unsuitable.
+ *
+ * <p>
+ * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
+ * class; use of identity-sensitive operations (including reference equality
+ * ({@code ==}), identity hash code, or synchronization) on instances of
+ * {@code MonthDay} may have unpredictable results and should be avoided.
+ * The {@code equals} method should be used for comparisons.
+ *
+ * @implSpec
+ * This class is immutable and thread-safe.
+ *
+ * @since 1.8
+ */
+public final class MonthDay
+        implements TemporalAccessor, TemporalAdjuster, Comparable<MonthDay>, Serializable {
+
+    /**
+     * Serialization version.
+     */
+    private static final long serialVersionUID = -939150713474957432L;
+    /**
+     * Parser.
+     */
+    private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder()
+        .appendLiteral("--")
+        .appendValue(MONTH_OF_YEAR, 2)
+        .appendLiteral('-')
+        .appendValue(DAY_OF_MONTH, 2)
+        .toFormatter();
+
+    /**
+     * The month-of-year, not null.
+     */
+    private final int month;
+    /**
+     * The day-of-month.
+     */
+    private final int day;
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains the current month-day from the system clock in the default time-zone.
+     * <p>
+     * This will query the {@link Clock#systemDefaultZone() system clock} in the default
+     * time-zone to obtain the current month-day.
+     * <p>
+     * Using this method will prevent the ability to use an alternate clock for testing
+     * because the clock is hard-coded.
+     *
+     * @return the current month-day using the system clock and default time-zone, not null
+     */
+    public static MonthDay now() {
+        return now(Clock.systemDefaultZone());
+    }
+
+    /**
+     * Obtains the current month-day from the system clock in the specified time-zone.
+     * <p>
+     * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current month-day.
+     * Specifying the time-zone avoids dependence on the default time-zone.
+     * <p>
+     * Using this method will prevent the ability to use an alternate clock for testing
+     * because the clock is hard-coded.
+     *
+     * @param zone  the zone ID to use, not null
+     * @return the current month-day using the system clock, not null
+     */
+    public static MonthDay now(ZoneId zone) {
+        return now(Clock.system(zone));
+    }
+
+    /**
+     * Obtains the current month-day from the specified clock.
+     * <p>
+     * This will query the specified clock to obtain the current month-day.
+     * Using this method allows the use of an alternate clock for testing.
+     * The alternate clock may be introduced using {@link Clock dependency injection}.
+     *
+     * @param clock  the clock to use, not null
+     * @return the current month-day, not null
+     */
+    public static MonthDay now(Clock clock) {
+        final LocalDate now = LocalDate.now(clock);  // called once
+        return MonthDay.of(now.getMonth(), now.getDayOfMonth());
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an instance of {@code MonthDay}.
+     * <p>
+     * The day-of-month must be valid for the month within a leap year.
+     * Hence, for February, day 29 is valid.
+     * <p>
+     * For example, passing in April and day 31 will throw an exception, as
+     * there can never be April 31st in any year. By contrast, passing in
+     * February 29th is permitted, as that month-day can sometimes be valid.
+     *
+     * @param month  the month-of-year to represent, not null
+     * @param dayOfMonth  the day-of-month to represent, from 1 to 31
+     * @return the month-day, not null
+     * @throws DateTimeException if the value of any field is out of range,
+     *  or if the day-of-month is invalid for the month
+     */
+    public static MonthDay of(Month month, int dayOfMonth) {
+        Objects.requireNonNull(month, "month");
+        DAY_OF_MONTH.checkValidValue(dayOfMonth);
+        if (dayOfMonth > month.maxLength()) {
+            throw new DateTimeException("Illegal value for DayOfMonth field, value " + dayOfMonth +
+                    " is not valid for month " + month.name());
+        }
+        return new MonthDay(month.getValue(), dayOfMonth);
+    }
+
+    /**
+     * Obtains an instance of {@code MonthDay}.
+     * <p>
+     * The day-of-month must be valid for the month within a leap year.
+     * Hence, for month 2 (February), day 29 is valid.
+     * <p>
+     * For example, passing in month 4 (April) and day 31 will throw an exception, as
+     * there can never be April 31st in any year. By contrast, passing in
+     * February 29th is permitted, as that month-day can sometimes be valid.
+     *
+     * @param month  the month-of-year to represent, from 1 (January) to 12 (December)
+     * @param dayOfMonth  the day-of-month to represent, from 1 to 31
+     * @return the month-day, not null
+     * @throws DateTimeException if the value of any field is out of range,
+     *  or if the day-of-month is invalid for the month
+     */
+    public static MonthDay of(int month, int dayOfMonth) {
+        return of(Month.of(month), dayOfMonth);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an instance of {@code MonthDay} from a temporal object.
+     * <p>
+     * This obtains a month-day based on the specified temporal.
+     * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
+     * which this factory converts to an instance of {@code MonthDay}.
+     * <p>
+     * The conversion extracts the {@link ChronoField#MONTH_OF_YEAR MONTH_OF_YEAR} and
+     * {@link ChronoField#DAY_OF_MONTH DAY_OF_MONTH} fields.
+     * The extraction is only permitted if the temporal object has an ISO
+     * chronology, or can be converted to a {@code LocalDate}.
+     * <p>
+     * This method matches the signature of the functional interface {@link TemporalQuery}
+     * allowing it to be used as a query via method reference, {@code MonthDay::from}.
+     *
+     * @param temporal  the temporal object to convert, not null
+     * @return the month-day, not null
+     * @throws DateTimeException if unable to convert to a {@code MonthDay}
+     */
+    public static MonthDay from(TemporalAccessor temporal) {
+        if (temporal instanceof MonthDay) {
+            return (MonthDay) temporal;
+        }
+        try {
+            if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) {
+                temporal = LocalDate.from(temporal);
+            }
+            return of(temporal.get(MONTH_OF_YEAR), temporal.get(DAY_OF_MONTH));
+        } catch (DateTimeException ex) {
+            throw new DateTimeException("Unable to obtain MonthDay from TemporalAccessor: " +
+                    temporal + " of type " + temporal.getClass().getName(), ex);
+        }
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Obtains an instance of {@code MonthDay} from a text string such as {@code --12-03}.
+     * <p>
+     * The string must represent a valid month-day.
+     * The format is {@code --MM-dd}.
+     *
+     * @param text  the text to parse such as "--12-03", not null
+     * @return the parsed month-day, not null
+     * @throws DateTimeParseException if the text cannot be parsed
+     */
+    public static MonthDay parse(CharSequence text) {
+        return parse(text, PARSER);
+    }
+
+    /**
+     * Obtains an instance of {@code MonthDay} from a text string using a specific formatter.
+     * <p>
+     * The text is parsed using the formatter, returning a month-day.
+     *
+     * @param text  the text to parse, not null
+     * @param formatter  the formatter to use, not null
+     * @return the parsed month-day, not null
+     * @throws DateTimeParseException if the text cannot be parsed
+     */
+    public static MonthDay parse(CharSequence text, DateTimeFormatter formatter) {
+        Objects.requireNonNull(formatter, "formatter");
+        return formatter.parse(text, MonthDay::from);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Constructor, previously validated.
+     *
+     * @param month  the month-of-year to represent, validated from 1 to 12
+     * @param dayOfMonth  the day-of-month to represent, validated from 1 to 29-31
+     */
+    private MonthDay(int month, int dayOfMonth) {
+        this.month = month;
+        this.day = dayOfMonth;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if the specified field is supported.
+     * <p>
+     * This checks if this month-day can be queried for the specified field.
+     * If false, then calling the {@link #range(TemporalField) range} and
+     * {@link #get(TemporalField) get} methods will throw an exception.
+     * <p>
+     * If the field is a {@link ChronoField} then the query is implemented here.
+     * The supported fields are:
+     * <ul>
+     * <li>{@code MONTH_OF_YEAR}
+     * <li>{@code YEAR}
+     * </ul>
+     * All other {@code ChronoField} instances will return false.
+     * <p>
+     * If the field is not a {@code ChronoField}, then the result of this method
+     * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
+     * passing {@code this} as the argument.
+     * Whether the field is supported is determined by the field.
+     *
+     * @param field  the field to check, null returns false
+     * @return true if the field is supported on this month-day, false if not
+     */
+    @Override
+    public boolean isSupported(TemporalField field) {
+        if (field instanceof ChronoField) {
+            return field == MONTH_OF_YEAR || field == DAY_OF_MONTH;
+        }
+        return field != null && field.isSupportedBy(this);
+    }
+
+    /**
+     * Gets the range of valid values for the specified field.
+     * <p>
+     * The range object expresses the minimum and maximum valid values for a field.
+     * This month-day is used to enhance the accuracy of the returned range.
+     * If it is not possible to return the range, because the field is not supported
+     * or for some other reason, an exception is thrown.
+     * <p>
+     * If the field is a {@link ChronoField} then the query is implemented here.
+     * The {@link #isSupported(TemporalField) supported fields} will return
+     * appropriate range instances.
+     * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
+     * <p>
+     * If the field is not a {@code ChronoField}, then the result of this method
+     * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
+     * passing {@code this} as the argument.
+     * Whether the range can be obtained is determined by the field.
+     *
+     * @param field  the field to query the range for, not null
+     * @return the range of valid values for the field, not null
+     * @throws DateTimeException if the range for the field cannot be obtained
+     * @throws UnsupportedTemporalTypeException if the field is not supported
+     */
+    @Override
+    public ValueRange range(TemporalField field) {
+        if (field == MONTH_OF_YEAR) {
+            return field.range();
+        } else if (field == DAY_OF_MONTH) {
+            return ValueRange.of(1, getMonth().minLength(), getMonth().maxLength());
+        }
+        return TemporalAccessor.super.range(field);
+    }
+
+    /**
+     * Gets the value of the specified field from this month-day as an {@code int}.
+     * <p>
+     * This queries this month-day for the value of the specified field.
+     * The returned value will always be within the valid range of values for the field.
+     * If it is not possible to return the value, because the field is not supported
+     * or for some other reason, an exception is thrown.
+     * <p>
+     * If the field is a {@link ChronoField} then the query is implemented here.
+     * The {@link #isSupported(TemporalField) supported fields} will return valid
+     * values based on this month-day.
+     * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
+     * <p>
+     * If the field is not a {@code ChronoField}, then the result of this method
+     * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
+     * passing {@code this} as the argument. Whether the value can be obtained,
+     * and what the value represents, is determined by the field.
+     *
+     * @param field  the field to get, not null
+     * @return the value for the field
+     * @throws DateTimeException if a value for the field cannot be obtained or
+     *         the value is outside the range of valid values for the field
+     * @throws UnsupportedTemporalTypeException if the field is not supported or
+     *         the range of values exceeds an {@code int}
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    @Override  // override for Javadoc
+    public int get(TemporalField field) {
+        return range(field).checkValidIntValue(getLong(field), field);
+    }
+
+    /**
+     * Gets the value of the specified field from this month-day as a {@code long}.
+     * <p>
+     * This queries this month-day for the value of the specified field.
+     * If it is not possible to return the value, because the field is not supported
+     * or for some other reason, an exception is thrown.
+     * <p>
+     * If the field is a {@link ChronoField} then the query is implemented here.
+     * The {@link #isSupported(TemporalField) supported fields} will return valid
+     * values based on this month-day.
+     * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
+     * <p>
+     * If the field is not a {@code ChronoField}, then the result of this method
+     * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
+     * passing {@code this} as the argument. Whether the value can be obtained,
+     * and what the value represents, is determined by the field.
+     *
+     * @param field  the field to get, not null
+     * @return the value for the field
+     * @throws DateTimeException if a value for the field cannot be obtained
+     * @throws UnsupportedTemporalTypeException if the field is not supported
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    @Override
+    public long getLong(TemporalField field) {
+        if (field instanceof ChronoField) {
+            switch ((ChronoField) field) {
+                // alignedDOW and alignedWOM not supported because they cannot be set in with()
+                case DAY_OF_MONTH: return day;
+                case MONTH_OF_YEAR: return month;
+            }
+            throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
+        }
+        return field.getFrom(this);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Gets the month-of-year field from 1 to 12.
+     * <p>
+     * This method returns the month as an {@code int} from 1 to 12.
+     * Application code is frequently clearer if the enum {@link Month}
+     * is used by calling {@link #getMonth()}.
+     *
+     * @return the month-of-year, from 1 to 12
+     * @see #getMonth()
+     */
+    public int getMonthValue() {
+        return month;
+    }
+
+    /**
+     * Gets the month-of-year field using the {@code Month} enum.
+     * <p>
+     * This method returns the enum {@link Month} for the month.
+     * This avoids confusion as to what {@code int} values mean.
+     * If you need access to the primitive {@code int} value then the enum
+     * provides the {@link Month#getValue() int value}.
+     *
+     * @return the month-of-year, not null
+     * @see #getMonthValue()
+     */
+    public Month getMonth() {
+        return Month.of(month);
+    }
+
+    /**
+     * Gets the day-of-month field.
+     * <p>
+     * This method returns the primitive {@code int} value for the day-of-month.
+     *
+     * @return the day-of-month, from 1 to 31
+     */
+    public int getDayOfMonth() {
+        return day;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if the year is valid for this month-day.
+     * <p>
+     * This method checks whether this month and day and the input year form
+     * a valid date. This can only return false for February 29th.
+     *
+     * @param year  the year to validate
+     * @return true if the year is valid for this month-day
+     * @see Year#isValidMonthDay(MonthDay)
+     */
+    public boolean isValidYear(int year) {
+        return (day == 29 && month == 2 && Year.isLeap(year) == false) == false;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Returns a copy of this {@code MonthDay} with the month-of-year altered.
+     * <p>
+     * This returns a month-day with the specified month.
+     * If the day-of-month is invalid for the specified month, the day will
+     * be adjusted to the last valid day-of-month.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param month  the month-of-year to set in the returned month-day, from 1 (January) to 12 (December)
+     * @return a {@code MonthDay} based on this month-day with the requested month, not null
+     * @throws DateTimeException if the month-of-year value is invalid
+     */
+    public MonthDay withMonth(int month) {
+        return with(Month.of(month));
+    }
+
+    /**
+     * Returns a copy of this {@code MonthDay} with the month-of-year altered.
+     * <p>
+     * This returns a month-day with the specified month.
+     * If the day-of-month is invalid for the specified month, the day will
+     * be adjusted to the last valid day-of-month.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param month  the month-of-year to set in the returned month-day, not null
+     * @return a {@code MonthDay} based on this month-day with the requested month, not null
+     */
+    public MonthDay with(Month month) {
+        Objects.requireNonNull(month, "month");
+        if (month.getValue() == this.month) {
+            return this;
+        }
+        int day = Math.min(this.day, month.maxLength());
+        return new MonthDay(month.getValue(), day);
+    }
+
+    /**
+     * Returns a copy of this {@code MonthDay} with the day-of-month altered.
+     * <p>
+     * This returns a month-day with the specified day-of-month.
+     * If the day-of-month is invalid for the month, an exception is thrown.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param dayOfMonth  the day-of-month to set in the return month-day, from 1 to 31
+     * @return a {@code MonthDay} based on this month-day with the requested day, not null
+     * @throws DateTimeException if the day-of-month value is invalid,
+     *  or if the day-of-month is invalid for the month
+     */
+    public MonthDay withDayOfMonth(int dayOfMonth) {
+        if (dayOfMonth == this.day) {
+            return this;
+        }
+        return of(month, dayOfMonth);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Queries this month-day using the specified query.
+     * <p>
+     * This queries this month-day using the specified query strategy object.
+     * The {@code TemporalQuery} object defines the logic to be used to
+     * obtain the result. Read the documentation of the query to understand
+     * what the result of this method will be.
+     * <p>
+     * The result of this method is obtained by invoking the
+     * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
+     * specified query passing {@code this} as the argument.
+     *
+     * @param <R> the type of the result
+     * @param query  the query to invoke, not null
+     * @return the query result, null may be returned (defined by the query)
+     * @throws DateTimeException if unable to query (defined by the query)
+     * @throws ArithmeticException if numeric overflow occurs (defined by the query)
+     */
+    @SuppressWarnings("unchecked")
+    @Override
+    public <R> R query(TemporalQuery<R> query) {
+        if (query == TemporalQueries.chronology()) {
+            return (R) IsoChronology.INSTANCE;
+        }
+        return TemporalAccessor.super.query(query);
+    }
+
+    /**
+     * Adjusts the specified temporal object to have this month-day.
+     * <p>
+     * This returns a temporal object of the same observable type as the input
+     * with the month and day-of-month changed to be the same as this.
+     * <p>
+     * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
+     * twice, passing {@link ChronoField#MONTH_OF_YEAR} and
+     * {@link ChronoField#DAY_OF_MONTH} as the fields.
+     * If the specified temporal object does not use the ISO calendar system then
+     * a {@code DateTimeException} is thrown.
+     * <p>
+     * In most cases, it is clearer to reverse the calling pattern by using
+     * {@link Temporal#with(TemporalAdjuster)}:
+     * <pre>
+     *   // these two lines are equivalent, but the second approach is recommended
+     *   temporal = thisMonthDay.adjustInto(temporal);
+     *   temporal = temporal.with(thisMonthDay);
+     * </pre>
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param temporal  the target object to be adjusted, not null
+     * @return the adjusted object, not null
+     * @throws DateTimeException if unable to make the adjustment
+     * @throws ArithmeticException if numeric overflow occurs
+     */
+    @Override
+    public Temporal adjustInto(Temporal temporal) {
+        if (Chronology.from(temporal).equals(IsoChronology.INSTANCE) == false) {
+            throw new DateTimeException("Adjustment only supported on ISO date-time");
+        }
+        temporal = temporal.with(MONTH_OF_YEAR, month);
+        return temporal.with(DAY_OF_MONTH, Math.min(temporal.range(DAY_OF_MONTH).getMaximum(), day));
+    }
+
+    /**
+     * Formats this month-day using the specified formatter.
+     * <p>
+     * This month-day will be passed to the formatter to produce a string.
+     *
+     * @param formatter  the formatter to use, not null
+     * @return the formatted month-day string, not null
+     * @throws DateTimeException if an error occurs during printing
+     */
+    public String format(DateTimeFormatter formatter) {
+        Objects.requireNonNull(formatter, "formatter");
+        return formatter.format(this);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Combines this month-day with a year to create a {@code LocalDate}.
+     * <p>
+     * This returns a {@code LocalDate} formed from this month-day and the specified year.
+     * <p>
+     * A month-day of February 29th will be adjusted to February 28th in the resulting
+     * date if the year is not a leap year.
+     * <p>
+     * This instance is immutable and unaffected by this method call.
+     *
+     * @param year  the year to use, from MIN_YEAR to MAX_YEAR
+     * @return the local date formed from this month-day and the specified year, not null
+     * @throws DateTimeException if the year is outside the valid range of years
+     */
+    public LocalDate atYear(int year) {
+        return LocalDate.of(year, month, isValidYear(year) ? day : 28);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Compares this month-day to another month-day.
+     * <p>
+     * The comparison is based first on value of the month, then on the value of the day.
+     * It is "consistent with equals", as defined by {@link Comparable}.
+     *
+     * @param other  the other month-day to compare to, not null
+     * @return the comparator value, negative if less, positive if greater
+     */
+    @Override
+    public int compareTo(MonthDay other) {
+        int cmp = (month - other.month);
+        if (cmp == 0) {
+            cmp = (day - other.day);
+        }
+        return cmp;
+    }
+
+    /**
+     * Checks if this month-day is after the specified month-day.
+     *
+     * @param other  the other month-day to compare to, not null
+     * @return true if this is after the specified month-day
+     */
+    public boolean isAfter(MonthDay other) {
+        return compareTo(other) > 0;
+    }
+
+    /**
+     * Checks if this month-day is before the specified month-day.
+     *
+     * @param other  the other month-day to compare to, not null
+     * @return true if this point is before the specified month-day
+     */
+    public boolean isBefore(MonthDay other) {
+        return compareTo(other) < 0;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Checks if this month-day is equal to another month-day.
+     * <p>
+     * The comparison is based on the time-line position of the month-day within a year.
+     *
+     * @param obj  the object to check, null returns false
+     * @return true if this is equal to the other month-day
+     */
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof MonthDay) {
+            MonthDay other = (MonthDay) obj;
+            return month == other.month && day == other.day;
+        }
+        return false;
+    }
+
+    /**
+     * A hash code for this month-day.
+     *
+     * @return a suitable hash code
+     */
+    @Override
+    public int hashCode() {
+        return (month << 6) + day;
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Outputs this month-day as a {@code String}, such as {@code --12-03}.
+     * <p>
+     * The output will be in the format {@code --MM-dd}:
+     *
+     * @return a string representation of this month-day, not null
+     */
+    @Override
+    public String toString() {
+        return new StringBuilder(10).append("--")
+            .append(month < 10 ? "0" : "").append(month)
+            .append(day < 10 ? "-0" : "-").append(day)
+            .toString();
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Writes the object using a
+     * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
+     * @serialData
+     * <pre>
+     *  out.writeByte(13);  // identifies a MonthDay
+     *  out.writeByte(month);
+     *  out.writeByte(day);
+     * </pre>
+     *
+     * @return the instance of {@code Ser}, not null
+     */
+    private Object writeReplace() {
+        return new Ser(Ser.MONTH_DAY_TYPE, this);
+    }
+
+    /**
+     * Defend against malicious streams.
+     *
+     * @param s the stream to read
+     * @throws InvalidObjectException always
+     */
+    private void readObject(ObjectInputStream s) throws InvalidObjectException {
+        throw new InvalidObjectException("Deserialization via serialization delegate");
+    }
+
+    void writeExternal(DataOutput out) throws IOException {
+        out.writeByte(month);
+        out.writeByte(day);
+    }
+
+    static MonthDay readExternal(DataInput in) throws IOException {
+        byte month = in.readByte();
+        byte day = in.readByte();
+        return MonthDay.of(month, day);
+    }
+
+}