Enum Class Month

java.lang.Object
java.lang.Enum<Month>
java.time.Month
All Implemented Interfaces:
Serializable,Comparable<Month>,Constable,TemporalAccessor,TemporalAdjuster
public enumMonthextendsEnum<Month>implementsTemporalAccessor,TemporalAdjuster
A month-of-year, such as 'July'.

Month is an enum representing the 12 months of the year - January, February, March, April, May, June, July, August, September, October, November and December.

In addition to the textual enum name, each month-of-year has anint value. Theint value follows normal usage and the ISO-8601 standard, from 1 (January) to 12 (December). It is recommended that applications use the enum rather than theint value to ensure code clarity.

Do not useordinal() to obtain the numeric representation ofMonth. UsegetValue() instead.

This enum represents a common concept that is found in many calendar systems. As such, this enum may be used by any calendar system that has the month-of-year concept defined exactly equivalent to the ISO-8601 calendar system.

Implementation Requirements:
This is an immutable and thread-safe enum.
Since:
1.8

  • Nested Class Summary

    Nested classes/interfaces declared in class java.lang.Enum

    Enum.EnumDesc<E extendsEnum<E>>

  • Enum Constant Summary

    Enum Constants
    Enum Constant
    Description
    The singleton instance for the month of April with 30 days.
    The singleton instance for the month of August with 31 days.
    The singleton instance for the month of December with 31 days.
    The singleton instance for the month of February with 28 days, or 29 in a leap year.
    The singleton instance for the month of January with 31 days.
    The singleton instance for the month of July with 31 days.
    The singleton instance for the month of June with 30 days.
    The singleton instance for the month of March with 31 days.
    The singleton instance for the month of May with 31 days.
    The singleton instance for the month of November with 30 days.
    The singleton instance for the month of October with 31 days.
    The singleton instance for the month of September with 30 days.

  • Method Summary

    Modifier and Type
    Method
    Description
    adjustInto(Temporal temporal)
    Adjusts the specified temporal object to have this month-of-year.
    int
    firstDayOfYear(boolean leapYear)
    Gets the day-of-year corresponding to the first day of this month.
    Gets the month corresponding to the first month of this quarter.
    staticMonth
    Obtains an instance ofMonth from a temporal object.
    int
    Gets the value of the specified field from this month-of-year as anint.
    Gets the textual representation, such as 'Jan' or 'December'.
    long
    Gets the value of the specified field from this month-of-year as along.
    int
    Gets the month-of-yearint value.
    boolean
    Checks if the specified field is supported.
    int
    length(boolean leapYear)
    Gets the length of this month in days.
    int
    Gets the maximum length of this month in days.
    int
    Gets the minimum length of this month in days.
    minus(long months)
    Returns the month-of-year that is the specified number of months before this one.
    staticMonth
    of(int month)
    Obtains an instance ofMonth from anint value.
    plus(long months)
    Returns the month-of-year that is the specified number of months after this one.
    <R> R
    query(TemporalQuery<R> query)
    Queries this month-of-year using the specified query.
    Gets the range of valid values for the specified field.
    staticMonth
    Returns the enum constant of this class with the specified name.
    staticMonth[]
    Returns an array containing the constants of this enum class, inthe order they are declared.

    Methods declared in class java.lang.Object

    getClass,notify,notifyAll,wait,wait,wait

  • Enum Constant Details

    • JANUARY

      public static final Month JANUARY
      The singleton instance for the month of January with 31 days. This has the numeric value of1.

    • FEBRUARY

      public static final Month FEBRUARY
      The singleton instance for the month of February with 28 days, or 29 in a leap year. This has the numeric value of2.

    • MARCH

      public static final Month MARCH
      The singleton instance for the month of March with 31 days. This has the numeric value of3.

    • APRIL

      public static final Month APRIL
      The singleton instance for the month of April with 30 days. This has the numeric value of4.

    • MAY

      public static final Month MAY
      The singleton instance for the month of May with 31 days. This has the numeric value of5.

    • JUNE

      public static final Month JUNE
      The singleton instance for the month of June with 30 days. This has the numeric value of6.

    • JULY

      public static final Month JULY
      The singleton instance for the month of July with 31 days. This has the numeric value of7.

    • AUGUST

      public static final Month AUGUST
      The singleton instance for the month of August with 31 days. This has the numeric value of8.

    • SEPTEMBER

      public static final Month SEPTEMBER
      The singleton instance for the month of September with 30 days. This has the numeric value of9.

    • OCTOBER

      public static final Month OCTOBER
      The singleton instance for the month of October with 31 days. This has the numeric value of10.

    • NOVEMBER

      public static final Month NOVEMBER
      The singleton instance for the month of November with 30 days. This has the numeric value of11.

    • DECEMBER

      public static final Month DECEMBER
      The singleton instance for the month of December with 31 days. This has the numeric value of12.

  • Method Details

    • values

      public static Month[] values()
      Returns an array containing the constants of this enum class, inthe order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static Month valueOf(String name)
      Returns the enum constant of this class with the specified name.The string must matchexactly an identifier used to declare anenum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • of

      public static Month of(int month)
      Obtains an instance ofMonth from anint value.

      Month is an enum representing the 12 months of the year. This factory allows the enum to be obtained from theint value. Theint value follows the ISO-8601 standard, from 1 (January) to 12 (December).

      Parameters:
      month - the month-of-year to represent, from 1 (January) to 12 (December)
      Returns:
      the month-of-year, not null
      Throws:
      DateTimeException - if the month-of-year is invalid

    • from

      public static Month from(TemporalAccessor temporal)
      Obtains an instance ofMonth from a temporal object.

      This obtains a month based on the specified temporal. ATemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance ofMonth.

      The conversion extracts theMONTH_OF_YEAR field. The extraction is only permitted if the temporal object has an ISO chronology, or can be converted to aLocalDate.

      This method matches the signature of the functional interfaceTemporalQuery allowing it to be used as a query via method reference,Month::from.

      Parameters:
      temporal - the temporal object to convert, not null
      Returns:
      the month-of-year, not null
      Throws:
      DateTimeException - if unable to convert to aMonth

    • getValue

      public int getValue()
      Gets the month-of-yearint value.

      The values are numbered following the ISO-8601 standard, from 1 (January) to 12 (December).

      Returns:
      the month-of-year, from 1 (January) to 12 (December)

    • getDisplayName

      public String getDisplayName(TextStyle style,Locale locale)
      Gets the textual representation, such as 'Jan' or 'December'.

      This returns the textual name used to identify the month-of-year, suitable for presentation to the user. The parameters control the style of the returned text and the locale.

      If no textual mapping is found then thenumeric value is returned.

      Parameters:
      style - the length of the text required, not null
      locale - the locale to use, not null
      Returns:
      the text value of the month-of-year, not null

    • isSupported

      public boolean isSupported(TemporalField field)
      Checks if the specified field is supported.

      This checks if this month-of-year can be queried for the specified field. If false, then calling therange andget methods will throw an exception.

      If the field isMONTH_OF_YEAR then this method returns true. All otherChronoField instances will return false.

      If the field is not aChronoField, then the result of this method is obtained by invokingTemporalField.isSupportedBy(TemporalAccessor) passingthis as the argument. Whether the field is supported is determined by the field.

      Specified by:
      isSupported in interface TemporalAccessor
      Parameters:
      field - the field to check, null returns false
      Returns:
      true if the field is supported on this month-of-year, false if not

    • range

      public ValueRange range(TemporalField field)
      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 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 isMONTH_OF_YEAR then the range of the month-of-year, from 1 to 12, will be returned. All otherChronoField instances will throw anUnsupportedTemporalTypeException.

      If the field is not aChronoField, then the result of this method is obtained by invokingTemporalField.rangeRefinedBy(TemporalAccessor) passingthis as the argument. Whether the range can be obtained is determined by the field.

      Specified by:
      range in interface TemporalAccessor
      Parameters:
      field - the field to query the range for, not null
      Returns:
      the range of valid values for the field, not null
      Throws:
      DateTimeException - if the range for the field cannot be obtained
      UnsupportedTemporalTypeException - if the field is not supported

    • get

      public int get(TemporalField field)
      Gets the value of the specified field from this month-of-year as anint.

      This queries this month 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.

      If the field isMONTH_OF_YEAR then the value of the month-of-year, from 1 to 12, will be returned. All otherChronoField instances will throw anUnsupportedTemporalTypeException.

      If the field is not aChronoField, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor) passingthis as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.

      Specified by:
      get in interface TemporalAccessor
      Parameters:
      field - the field to get, not null
      Returns:
      the value for the field, within the valid range of values
      Throws:
      DateTimeException - if a value for the field cannot be obtained or the value is outside the range of valid values for the field
      UnsupportedTemporalTypeException - if the field is not supported or the range of values exceeds anint
      ArithmeticException - if numeric overflow occurs

    • getLong

      public long getLong(TemporalField field)
      Gets the value of the specified field from this month-of-year as along.

      This queries this month 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.

      If the field isMONTH_OF_YEAR then the value of the month-of-year, from 1 to 12, will be returned. All otherChronoField instances will throw anUnsupportedTemporalTypeException.

      If the field is not aChronoField, then the result of this method is obtained by invokingTemporalField.getFrom(TemporalAccessor) passingthis as the argument. Whether the value can be obtained, and what the value represents, is determined by the field.

      Specified by:
      getLong in interface TemporalAccessor
      Parameters:
      field - the field to get, not null
      Returns:
      the value for the field
      Throws:
      DateTimeException - if a value for the field cannot be obtained
      UnsupportedTemporalTypeException - if the field is not supported
      ArithmeticException - if numeric overflow occurs

    • plus

      public Month plus(long months)
      Returns the month-of-year that is the specified number of months after this one.

      The calculation rolls around the end of the year from December to January. The specified period may be negative.

      This instance is immutable and unaffected by this method call.

      Parameters:
      months - the months to add, positive or negative
      Returns:
      the resulting month, not null

    • minus

      public Month minus(long months)
      Returns the month-of-year that is the specified number of months before this one.

      The calculation rolls around the start of the year from January to December. The specified period may be negative.

      This instance is immutable and unaffected by this method call.

      Parameters:
      months - the months to subtract, positive or negative
      Returns:
      the resulting month, not null

    • length

      public int length(boolean leapYear)
      Gets the length of this month in days.

      This takes a flag to determine whether to return the length for a leap year or not.

      February has 28 days in a standard year and 29 days in a leap year. April, June, September and November have 30 days. All other months have 31 days.

      Parameters:
      leapYear - true if the length is required for a leap year
      Returns:
      the length of this month in days, from 28 to 31

    • minLength

      public int minLength()
      Gets the minimum length of this month in days.

      February has a minimum length of 28 days. April, June, September and November have 30 days. All other months have 31 days.

      Returns:
      the minimum length of this month in days, from 28 to 31

    • maxLength

      public int maxLength()
      Gets the maximum length of this month in days.

      February has a maximum length of 29 days. April, June, September and November have 30 days. All other months have 31 days.

      Returns:
      the maximum length of this month in days, from 29 to 31

    • firstDayOfYear

      public int firstDayOfYear(boolean leapYear)
      Gets the day-of-year corresponding to the first day of this month.

      This returns the day-of-year that this month begins on, using the leap year flag to determine the length of February.

      Parameters:
      leapYear - true if the length is required for a leap year
      Returns:
      the day of year corresponding to the first day of this month, from 1 to 336

    • firstMonthOfQuarter

      public Month firstMonthOfQuarter()
      Gets the month corresponding to the first month of this quarter.

      The year can be divided into four quarters. This method returns the first month of the quarter for the base month. January, February and March return January. April, May and June return April. July, August and September return July. October, November and December return October.

      Returns:
      the first month of the quarter corresponding to this month, not null

    • query

      public <R> R query(TemporalQuery<R> query)
      Queries this month-of-year using the specified query.

      This queries this month-of-year using the specified query strategy object. TheTemporalQuery 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 theTemporalQuery.queryFrom(TemporalAccessor) method on the specified query passingthis as the argument.

      Specified by:
      query in interface TemporalAccessor
      Type Parameters:
      R - the type of the result
      Parameters:
      query - the query to invoke, not null
      Returns:
      the query result, null may be returned (defined by the query)
      Throws:
      DateTimeException - if unable to query (defined by the query)
      ArithmeticException - if numeric overflow occurs (defined by the query)

    • adjustInto

      public Temporal adjustInto(Temporal temporal)
      Adjusts the specified temporal object to have this month-of-year.

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

      The adjustment is equivalent to usingTemporal.with(TemporalField, long) passingChronoField.MONTH_OF_YEAR as the field. If the specified temporal object does not use the ISO calendar system then aDateTimeException is thrown.

      In most cases, it is clearer to reverse the calling pattern by usingTemporal.with(TemporalAdjuster):

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

      For example, given a date in May, the following are output:

         dateInMay.with(JANUARY);    // four months earlier   dateInMay.with(APRIL);      // one months earlier   dateInMay.with(MAY);        // same date   dateInMay.with(JUNE);       // one month later   dateInMay.with(DECEMBER);   // seven months later

      This instance is immutable and unaffected by this method call.

      Specified by:
      adjustInto in interface TemporalAdjuster
      Parameters:
      temporal - the target object to be adjusted, not null
      Returns:
      the adjusted object, not null
      Throws:
      DateTimeException - if unable to make the adjustment
      ArithmeticException - if numeric overflow occurs