- * {@code MonthDay} is an immutable date-time object that represents the combination - * of a year and month. Any field that can be derived from a month and day, such as - * quarter-of-year, can be obtained. - *
- * 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}. - *
- * Since a {@code MonthDay} does not possess a year, the leap day of - * February 29th is considered valid. - *
- * 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}. - *
- * 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. - * - *
- * This will query the {@link java.time.Clock#systemDefaultZone() system clock} in the default - * time-zone to obtain the current month-day. - *
- * 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. - *
- * This will query the {@link Clock#system(java.time.ZoneId) system clock} to obtain the current month-day. - * Specifying the time-zone avoids dependence on the default time-zone. - *
- * 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. - *
- * 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}. - *
- * The day-of-month must be valid for the month within a leap year. - * Hence, for February, day 29 is valid. - *
- * 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 - * @throws DateTimeException 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}. - *
- * The day-of-month must be valid for the month within a leap year. - * Hence, for month 2 (February), day 29 is valid. - *
- * 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 - * @throws DateTimeException 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. - *
- * A {@code TemporalAccessor} represents some form of date and time information. - * This factory converts the arbitrary temporal object to an instance of {@code MonthDay}. - *
- * 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 date-time has an ISO chronology. - *
- * This method matches the signature of the functional interface {@link TemporalQuery} - * allowing it to be used in queries 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 (ISOChrono.INSTANCE.equals(Chrono.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.getClass(), ex); - } - } - - //----------------------------------------------------------------------- - /** - * Obtains an instance of {@code MonthDay} from a text string such as {@code --12-03}. - *
- * 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. - *
- * 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. - *
- * 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. - *
- * 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 date-time. - * The supported fields are: - *
- * If the field is not a {@code ChronoField}, then the result of this method - * is obtained by invoking {@code TemporalField.doIsSupported(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.doIsSupported(this); - } - - /** - * Gets the range of valid values for the specified field. - *
- * 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. - *
- * 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 a {@code DateTimeException}. - *
- * If the field is not a {@code ChronoField}, then the result of this method - * is obtained by invoking {@code TemporalField.doRange(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 - */ - @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}. - *
- * This queries this month-day for the value for 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. - *
- * 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 a {@code DateTimeException}. - *
- * If the field is not a {@code ChronoField}, then the result of this method - * is obtained by invoking {@code TemporalField.doGet(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 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}. - *
- * This queries this month-day for the value for 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. - *
- * 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 a {@code DateTimeException}. - *
- * If the field is not a {@code ChronoField}, then the result of this method - * is obtained by invoking {@code TemporalField.doGet(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 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 DateTimeException("Unsupported field: " + field.getName()); - } - return field.doGet(this); - } - - //----------------------------------------------------------------------- - /** - * Gets the month-of-year field using the {@code Month} enum. - *
- * 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 - */ - public Month getMonth() { - return Month.of(month); - } - - /** - * Gets the day-of-month field. - *
- * 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. - *
- * 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, an out of range value returns false - * @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. - *
- * 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. - *
- * 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. - *
- * 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. - *
- * 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. - *
- * 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. - *
- * 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 - * @throws DateTimeException 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. - *
- * 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. - *
- * 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
- * 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.
- *
- * 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.
- *
- * In most cases, it is clearer to reverse the calling pattern by using
- * {@link Temporal#with(TemporalAdjuster)}:
- *
- * 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 (Chrono.from(temporal).equals(ISOChrono.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));
- }
-
- //-----------------------------------------------------------------------
- /**
- * Returns a date formed from this month-day at the specified year.
- *
- * This combines this month-day and the specified year to form a {@code LocalDate}.
- * A month-day of February 29th will be adjusted to February 28th in the resulting
- * date if the year is not a leap year.
- *
- * 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
- * @see Year#atMonthDay(MonthDay)
- */
- public LocalDate atYear(int year) {
- return LocalDate.of(year, month, isValidYear(year) ? day : 28);
- }
-
- //-----------------------------------------------------------------------
- /**
- * Compares this month-day to another month-day.
- *
- * 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
- */
- public int compareTo(MonthDay other) {
- int cmp = (month - other.month);
- if (cmp == 0) {
- cmp = (day - other.day);
- }
- return cmp;
- }
-
- /**
- * Is this month-day 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;
- }
-
- /**
- * Is this month-day 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.
- *
- * 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}.
- *
- * 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();
- }
-
- /**
- * Outputs this month-day as a {@code String} using the formatter.
- *
- * This month-day will be passed to the formatter
- * {@link DateTimeFormatter#print(TemporalAccessor) print method}.
- *
- * @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 toString(DateTimeFormatter formatter) {
- Objects.requireNonNull(formatter, "formatter");
- return formatter.print(this);
- }
-
- //-----------------------------------------------------------------------
- /**
- * Writes the object using a
- * dedicated serialized form.
- *
- * // these two lines are equivalent, but the second approach is recommended
- * temporal = thisMonthDay.adjustInto(temporal);
- * temporal = temporal.with(thisMonthDay);
- *
- *
- * out.writeByte(6); // identifies this as a Year
- * out.writeByte(month);
- * out.writeByte(day);
- *
- *
- * @return the instance of {@code Ser}, not null
- */
- private Object writeReplace() {
- return new Ser(Ser.MONTH_DAY_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.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);
- }
-
-}