Class DayOfMonth

  • All Implemented Interfaces:
    Serializable, Comparable<DayOfMonth>, TemporalAccessor, TemporalAdjuster

    public final class DayOfMonth
    extends Object
    implements TemporalAccessor, TemporalAdjuster, Comparable<DayOfMonth>, Serializable
    A day-of-month in the ISO-8601 calendar system.

    DayOfMonth is an immutable date-time object that represents a day-of-month. It is a type-safe way of representing a day-of-month in an application. Any field that can be derived from a day-of-month can be obtained.

    This class does not store or represent a year, month, time or time-zone. For example, the value "21" can be stored in a DayOfMonth and would represent the 21st day of any month.

    Implementation Requirements:

    This class is immutable and thread-safe.

    This class must be treated as a value type. Do not synchronize, rely on the identity hash code or use the distinction between equals() and ==.

    See Also:
    Serialized Form
    • Method Detail

      • now

        public static DayOfMonth now()
        Obtains the current day-of-month from the system clock in the default time-zone.

        This will query the system clock in the default time-zone to obtain the current day-of-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.

        Returns:
        the current day-of-month using the system clock and default time-zone, not null
      • now

        public static DayOfMonth now​(ZoneId zone)
        Obtains the current day-of-month from the system clock in the specified time-zone.

        This will query the system clock to obtain the current day-of-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.

        Parameters:
        zone - the zone ID to use, not null
        Returns:
        the current day-of-month using the system clock, not null
      • now

        public static DayOfMonth now​(Clock clock)
        Obtains the current day-of-month from the specified clock.

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

        Parameters:
        clock - the clock to use, not null
        Returns:
        the current day-of-month, not null
      • of

        public static DayOfMonth of​(int dayOfMonth)
        Obtains an instance of DayOfMonth.

        A day-of-month object represents one of the 31 days of the month, from 1 to 31.

        Parameters:
        dayOfMonth - the day-of-month to represent, from 1 to 31
        Returns:
        the day-of-month, not null
        Throws:
        DateTimeException - if the day-of-month is invalid
      • from

        public static DayOfMonth from​(TemporalAccessor temporal)
        Obtains an instance of DayOfMonth from a date-time object.

        This obtains a day-of-month based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of DayOfMonth.

        The conversion extracts the day-of-month field. 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, DayOfMonth::from.

        Parameters:
        temporal - the temporal object to convert, not null
        Returns:
        the day-of-month, not null
        Throws:
        DateTimeException - if unable to convert to a DayOfMonth
      • getValue

        public int getValue()
        Gets the day-of-month value.
        Returns:
        the day-of-month, from 1 to 31
      • isSupported

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

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

        If the field is a ChronoField then the query is implemented here. The supported fields are:

        • DAY_OF_MONTH
        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(TemporalAccessor) passing this 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 day-of-month, 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 day-of-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 will return appropriate range instances. All other ChronoField instances will throw an UnsupportedTemporalTypeException.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.rangeRefinedBy(TemporalAccessor) passing this 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 day-of-month as an int.

        This queries this day-of-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 will return valid values based on this day-of-month. All other ChronoField instances will throw an UnsupportedTemporalTypeException.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom(TemporalAccessor) passing this 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
        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 an int
        ArithmeticException - if numeric overflow occurs
      • getLong

        public long getLong​(TemporalField field)
        Gets the value of the specified field from this day-of-month as a long.

        This queries this day-of-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 will return valid values based on this day-of-month. All other ChronoField instances will throw an UnsupportedTemporalTypeException.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom(TemporalAccessor) passing this 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
      • isValidYearMonth

        public boolean isValidYearMonth​(YearMonth yearMonth)
        Checks if the year-month is valid for this year.

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

        Parameters:
        yearMonth - the year month to validate, null returns false
        Returns:
        true if the year and month are valid for this day
      • query

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

        This queries this day-of-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(TemporalAccessor) method on the specified query passing this 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 day-of-month.

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

        The adjustment is equivalent to using Temporal.with(TemporalField, long) passing ChronoField.DAY_OF_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(TemporalAdjuster):

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

        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
      • atMonth

        public MonthDay atMonth​(Month month)
        Combines this day-of-month with a month to create a MonthDay.

        This returns a MonthDay formed from this day and the specified month.

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

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

        If this day-of-month is invalid for the month then it will be changed to the last valid date for the month.

        Parameters:
        month - the month-of-year to use, not null
        Returns:
        the year-month formed from this year and the specified month, not null
      • atMonth

        public MonthDay atMonth​(int month)
        Combines this day-of-month with a month to create a MonthDay.

        This returns a MonthDay formed from this day and the specified month.

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

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

        If this day-of-month is invalid for the month then it will be changed to the last valid date for the month.

        Parameters:
        month - the month-of-year to use, from 1 (January) to 12 (December)
        Returns:
        the year-month formed from this year and the specified month, not null
        Throws:
        DateTimeException - if the month is invalid
      • atYearMonth

        public LocalDate atYearMonth​(YearMonth yearMonth)
        Combines this day-of-month with a year-month to create a LocalDate.

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

        If this day-of-month is invalid for the year-month then it will be changed to the last valid date for the month.

        Parameters:
        yearMonth - the year-month to use, not null
        Returns:
        the local date formed from this year and the specified year-month, not null
      • compareTo

        public int compareTo​(DayOfMonth other)
        Compares this day-of-month to another.

        The comparison is based on the value of the day. It is "consistent with equals", as defined by Comparable.

        Specified by:
        compareTo in interface Comparable<DayOfMonth>
        Parameters:
        other - the other day-of-month instance, not null
        Returns:
        the comparator value, negative if less, positive if greater
      • equals

        public boolean equals​(Object obj)
        Checks if this day-of-month is equal to another day-of-month.
        Overrides:
        equals in class Object
        Parameters:
        obj - the other day-of-month instance, null returns false
        Returns:
        true if the day-of-month is the same
      • hashCode

        public int hashCode()
        A hash code for this day-of-month.
        Overrides:
        hashCode in class Object
        Returns:
        a suitable hash code
      • toString

        public String toString()
        Outputs this day-of-month as a String.
        Overrides:
        toString in class Object
        Returns:
        a string representation of this day-of-month, not null