YearMonth

Obtains an instance of YearMonth from a temporal object.

A TemporalAccessor represents some form of date and time information. This factory converts the arbitrary temporal object to an instance of YearMonth.

The conversion extracts the ChronoField#YEAR and ChronoField#MONTH_OF_YEAR fields. The extraction is only permitted if the temporal object has an ISO chronology, or can be converted to a LocalDate.

This method matches the signature of the functional interface TemporalQuery allowing it to be used in queries via method reference, YearMonth::from.

Throw:

function overloading for YearMonth.now

if called with 0 argument YearMonth.now0 is executed,

if called with 1 argument and first argument is an instance of ZoneId, then YearMonth.nowZoneId is executed,

otherwise YearMonth.nowClock is executed

Obtains the current year-month from the system clock in the default time-zone.

This will query the system clock (see Clock#systemDefaultZone) in the default time-zone to obtain the current year-month. The zone and offset will be set based on the time-zone in the clock.

Using this method will prevent the ability to use an alternate clock for testing because the clock is hard-coded.

Obtains the current year-month from the specified clock.

This will query the specified clock to obtain the current year-month. Using this method allows the use of an alternate clock for testing. The alternate clock may be introduced using dependency injection.

Obtains the current year-month from the system clock in the specified time-zone.

This will query the system clock (see Clock#system) to obtain the current year-month. 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.

function overloading for YearMonth.of

if called with 2 argument and first argument is an instance of Month, then YearMonth.ofNumberMonth is executed,

otherwise YearMonth.ofNumberNumber is executed

Obtains an instance of YearMonth from a year and month.

Throw:

Obtains an instance of YearMonth from a year and month.

Throw:

function overloading for YearMonth.parse

if called with 2 argument and first argument is an instance of Month, then YearMonth.parseString is executed,

otherwise YearMonth.parseStringFormatter is executed

Obtains an instance of YearMonth from a text string such as 2007-12.

The string must represent a valid year-month. The format must be yyyy-MM. Years outside the range 0000 to 9999 must be prefixed by the plus or minus symbol.

Throw:

Obtains an instance of YearMonth from a text string using a specific formatter.

The text is parsed using the formatter, returning a year-month.

Throw:

Adjusts the specified temporal object to have this year-month.

This returns a temporal object of the same observable type as the input with the year and month changed to be the same as this.

The adjustment is equivalent to using Temporal#with passing ChronoField#PROLEPTIC_MONTH as the field. If the specified temporal object does not use the ISO calendar system then a DateTimeException is thrown.

In most cases, it is clearer to reverse the calling pattern by using Temporal#with:

  // these two lines are equivalent, but the second approach is recommended
  temporal = thisYearMonth.adjustInto(temporal);
  temporal = temporal.with(thisYearMonth);

This instance is immutable and unaffected by this method call.

Throw:

Combines this year-month with a day-of-month to create a LocalDate.

This returns a LocalDate formed from this year-month and the specified day-of-month.

The day-of-month value must be valid for the year-month.

This method can be used as part of a chain to produce a date:

 LocalDate date = year.atMonth(month).atDay(day);

Throw:

See:

• #isValidDay(int)

Returns a LocalDate at the end of the month.

This returns a LocalDate based on this year-month. The day-of-month is set to the last valid day of the month, taking into account leap years.

This method can be used as part of a chain to produce a date:

 LocalDate date = year.atMonth(month).atEndOfMonth();

Compares this year-month to another year-month.

The comparison is based first on the value of the year, then on the value of the month. It is "consistent with equals", as defined by Comparable.

Checks if this year-month is equal to another year-month.

The comparison is based on the time-line position of the year-months.

Outputs this year-month as a string using the formatter.

Throw:

Gets the value of the specified field from this year-month as an int.

This queries this year-month 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 ChronoField then the query is implemented here. The supported fields (see isSupported) will return valid values based on this year-month, except EPOCH_MONTH which is too large to fit in an int and throw a DateTimeException. All other ChronoField instances will throw a DateTimeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom passing this as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.

Override:

Throw:

Gets the value of the specified field from this year-month as a long.

This queries this year-month 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 ChronoField then the query is implemented here. The supported fields (see isSupported) will return valid values based on this year-month. All other ChronoField instances will throw a DateTimeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom passing this as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.

Override:

Throw:

Is this year-month after the specified year-month.

Is this year-month before the specified year-month.

Checks if the year is a leap year, according to the ISO proleptic calendar system rules.

This method applies the current rules for leap years across the whole time-line. In general, a year is a leap year if it is divisible by four without remainder. However, years divisible by 100, are not leap years, with the exception of years divisible by 400 which are.

For example, 1904 is a leap year it is divisible by 4. 1900 was not a leap year as it is divisible by 100, however 2000 was a leap year as it is divisible by 400.

The calculation is proleptic - applying the same rules into the far future and far past. This is historically inaccurate, but is correct for the ISO-8601 standard.

function overloading for YearMonth.isSupported

if called with 1 argument and first argument is an instance of TemporalField, then YearMonth.isSupportedField is executed,

otherwise YearMonth.isSupportedUnit is executed

Override:

Checks if the specified field is supported.

This checks if this year-month can be queried for the specified field. If false, then calling range and get will throw an exception.

If the field is a ChronoField then the query is implemented here. The supported fields (see isSupported) will return valid values based on this date-time. The supported fields are:

• MONTH_OF_YEAR
• EPOCH_MONTH
• YEAR_OF_ERA
• YEAR
• ERA

All other ChronoField instances will return false.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.isSupportedBy passing this as the argument. Whether the field is supported is determined by the field.

Checks if the day-of-month is valid for this year-month.

This method checks whether this year and month and the input day form a valid date.

Returns the length of the month, taking account of the year.

This returns the length of the month in days. For example, a date in January would return 31.

Returns the length of the year.

This returns the length of the year in days, either 365 or 366.

Returns a copy of this year-month with the specified period in months subtracted.

This instance is immutable and unaffected by this method call.

Throw:

Returns a copy of this year-month with the specified period in years subtracted.

This instance is immutable and unaffected by this method call.

Throw:

Gets the month-of-year field using the Month enum.

This method returns the enum Month for the month. This avoids confusion as to what int values mean. If you need access to the primitive int value, use Month#getValue.

Gets the month-of-year field from 1 to 12.

This method returns the month as an int from 1 to 12. Application code is frequently clearer if the enum Month is used by calling getMonth.

See:

• #getMonth()

Returns a copy of this year-month with the specified period in months added.

This instance is immutable and unaffected by this method call.

Throw:

Returns a copy of this year-month with the specified period in years added.

This instance is immutable and unaffected by this method call.

Throw:

Queries this year-month using the specified query.

This queries this year-month using the specified query strategy object. The 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 TemporalQuery#queryFrom method on the specified query passing this as the argument.

Override:

Throw:

Gets the range of valid values for the specified field.

The range object expresses the minimum and maximum valid values for a field. This year-month 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 ChronoField then the query is implemented here. The supported fields (see isSupported) will return appropriate range instances. All other ChronoField instances will throw a DateTimeException.

If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.rangeRefinedBy passing this as the argument. Whether the range can be obtained is determined by the field.

Override:

Throw:

toJSON() use by JSON.stringify delegates to toString()

Outputs this year-month as a string, such as 2007-12.

The output will be in the format yyyy-MM:

Calculates the period between this year-month and another year-month in terms of the specified unit.

This calculates the period between two year-months in terms of a single unit. The start and end points are this and the specified year-month. The result will be negative if the end is before the start. The Temporal passed to this method must be a YearMonth. For example, the period in years between two year-months can be calculated using startYearMonth.until.

The calculation returns a whole number, representing the number of complete units between the two year-months. For example, the period in decades between 2012-06 and 2032-05 will only be one decade as it is one month short of two decades.

This method operates in association with TemporalUnit#between. The result of this method is a long representing the amount of the specified unit. By contrast, the result of between is an object that can be used directly in addition/subtraction:

  long period = start.until(end, YEARS);   // this method
  dateTime.plus(YEARS.between(start, end));      // use in plus/minus

The calculation is implemented in this method for ChronoUnit. The units MONTHS, YEARS, DECADES, CENTURIES, MILLENNIA and ERAS are supported. Other ChronoUnit values will throw an exception.

If the unit is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.between passing this as the first argument and the input temporal as the second argument.

This instance is immutable and unaffected by this method call.

Override:

Throw:

function overloading for YearMonth.with

if called with 1 argument, then YearMonth.withAdjuster is executed, otherwise YearMonth.withFieldValue is executed.

Override:

Returns a copy of this YearMonth with the month-of-year altered.

This instance is immutable and unaffected by this method call.

Throw:

Returns a copy of this YearMonth with the year altered.

This instance is immutable and unaffected by this method call.

Throw:

Gets the year field.

This method returns the primitive int value for the year.

The year returned by this method is proleptic as per get.