Package org.joda.time

Class Months

java.lang.Object

org.joda.time.base.BaseSingleFieldPeriod

org.joda.time.Months

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<BaseSingleFieldPeriod>, ReadablePeriod

public final class Months
extends BaseSingleFieldPeriod

An immutable time period representing a number of months.

Months is an immutable period that can only store months. It does not store years, days or hours for example. As such it is a type-safe way of representing a number of months in an application.

The number of months is set in the constructor, and may be queried using getMonths(). Basic mathematical operations are provided - plus(), minus(), multipliedBy() and dividedBy().

Months is thread-safe and immutable.

Since:

1.4

Author:

Stephen Colebourne

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static Months	EIGHT	Constant representing eight months.
static Months	ELEVEN	Constant representing eleven months.
static Months	FIVE	Constant representing five months.
static Months	FOUR	Constant representing four months.
static Months	MAX_VALUE	Constant representing the maximum number of months that can be stored in this object.
static Months	MIN_VALUE	Constant representing the minimum number of months that can be stored in this object.
static Months	NINE	Constant representing nine months.
static Months	ONE	Constant representing one month.
static Months	SEVEN	Constant representing seven months.
static Months	SIX	Constant representing six months.
static Months	TEN	Constant representing ten months.
static Months	THREE	Constant representing three months.
static Months	TWELVE	Constant representing twelve months.
static Months	TWO	Constant representing two months.
static Months	ZERO	Constant representing zero months.

Method Summary

Modifier and Type	Method	Description
Months	dividedBy(int divisor)	Returns a new instance with the months divided by the specified divisor.
DurationFieldType	getFieldType()	Gets the duration field type, which is months.
int	getMonths()	Gets the number of months that this period represents.
PeriodType	getPeriodType()	Gets the period type, which is months.
boolean	isGreaterThan(Months other)	Is this months instance greater than the specified number of months.
boolean	isLessThan(Months other)	Is this months instance less than the specified number of months.
Months	minus(int months)	Returns a new instance with the specified number of months taken away.
Months	minus(Months months)	Returns a new instance with the specified number of months taken away.
static Months	months(int months)	Obtains an instance of Months that may be cached.
static Months	monthsBetween(ReadableInstant start, ReadableInstant end)	Creates a Months representing the number of whole months between the two specified datetimes.
static Months	monthsBetween(ReadablePartial start, ReadablePartial end)	Creates a Months representing the number of whole months between the two specified partial datetimes.
static Months	monthsIn(ReadableInterval interval)	Creates a Months representing the number of whole months in the specified interval.
Months	multipliedBy(int scalar)	Returns a new instance with the months multiplied by the specified scalar.
Months	negated()	Returns a new instance with the months value negated.
static Months	parseMonths(java.lang.String periodStr)	Creates a new Months by parsing a string in the ISO8601 format 'PnM'.
Months	plus(int months)	Returns a new instance with the specified number of months added.
Months	plus(Months months)	Returns a new instance with the specified number of months added.
java.lang.String	toString()	Gets this instance as a String in the ISO8601 duration format.

Methods inherited from class org.joda.time.base.BaseSingleFieldPeriod

between, between, compareTo, equals, get, getFieldType, getValue, getValue, hashCode, isSupported, setValue, size, standardPeriodIn, toMutablePeriod, toPeriod

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

ZERO

public static final Months ZERO

Constant representing zero months.

ONE

public static final Months ONE

Constant representing one month.

TWO

public static final Months TWO

Constant representing two months.

THREE

public static final Months THREE

Constant representing three months.

FOUR

public static final Months FOUR

Constant representing four months.

FIVE

public static final Months FIVE

Constant representing five months.

SIX

public static final Months SIX

Constant representing six months.

SEVEN

public static final Months SEVEN

Constant representing seven months.

EIGHT

public static final Months EIGHT

Constant representing eight months.

NINE

public static final Months NINE

Constant representing nine months.

TEN

public static final Months TEN

Constant representing ten months.

ELEVEN

public static final Months ELEVEN

Constant representing eleven months.

TWELVE

public static final Months TWELVE

Constant representing twelve months.

MAX_VALUE

public static final Months MAX_VALUE

Constant representing the maximum number of months that can be stored in this object.

MIN_VALUE

public static final Months MIN_VALUE

Constant representing the minimum number of months that can be stored in this object.

Method Detail

months

public static Months months(int months)

Obtains an instance of Months that may be cached. Months is immutable, so instances can be cached and shared. This factory method provides access to shared instances.

Parameters:

months - the number of months to obtain an instance for

Returns:

the instance of Months

monthsBetween

public static Months monthsBetween(ReadableInstant start,
                                   ReadableInstant end)

Creates a Months representing the number of whole months between the two specified datetimes. This method correctly handles any daylight savings time changes that may occur during the interval.

This method calculates by adding months to the start date until the result is past the end date. As such, a period from the end of a "long" month to the end of a "short" month is counted as a whole month.

Parameters:

start - the start instant, must not be null

end - the end instant, must not be null

Returns:

the period in months

Throws:

java.lang.IllegalArgumentException - if the instants are null or invalid

monthsBetween

public static Months monthsBetween(ReadablePartial start,
                                   ReadablePartial end)

Creates a Months representing the number of whole months between the two specified partial datetimes.

The two partials must contain the same fields, for example you can specify two LocalDate objects.

This method calculates by adding months to the start date until the result is past the end date. As such, a period from the end of a "long" month to the end of a "short" month is counted as a whole month.

Parameters:

start - the start partial date, must not be null

end - the end partial date, must not be null

Returns:

the period in months

Throws:

java.lang.IllegalArgumentException - if the partials are null or invalid

monthsIn

public static Months monthsIn(ReadableInterval interval)

Creates a Months representing the number of whole months in the specified interval. This method correctly handles any daylight savings time changes that may occur during the interval.

Parameters:

interval - the interval to extract months from, null returns zero

Returns:

the period in months

Throws:

java.lang.IllegalArgumentException - if the partials are null or invalid

parseMonths

public static Months parseMonths(java.lang.String periodStr)

Creates a new Months by parsing a string in the ISO8601 format 'PnM'.

The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the months component may be non-zero. If any other component is non-zero, an exception will be thrown.

Parameters:

periodStr - the period string, null returns zero

Returns:

the period in months

Throws:

java.lang.IllegalArgumentException - if the string format is invalid

getFieldType

public DurationFieldType getFieldType()

Gets the duration field type, which is months.

Specified by:

getFieldType in class BaseSingleFieldPeriod

Returns:

the period type

getPeriodType

public PeriodType getPeriodType()

Gets the period type, which is months.

Specified by:

getPeriodType in interface ReadablePeriod

Specified by:

getPeriodType in class BaseSingleFieldPeriod

Returns:

the period type

getMonths

public int getMonths()

Gets the number of months that this period represents.

Returns:

the number of months in the period

plus

public Months plus(int months)

Returns a new instance with the specified number of months added.

This instance is immutable and unaffected by this method call.

Parameters:

months - the amount of months to add, may be negative

Returns:

the new period plus the specified number of months

Throws:

java.lang.ArithmeticException - if the result overflows an int

plus

public Months plus(Months months)

Returns a new instance with the specified number of months added.

This instance is immutable and unaffected by this method call.

Parameters:

months - the amount of months to add, may be negative, null means zero

Returns:

the new period plus the specified number of months

Throws:

java.lang.ArithmeticException - if the result overflows an int

minus

public Months minus(int months)

Returns a new instance with the specified number of months taken away.

This instance is immutable and unaffected by this method call.

Parameters:

months - the amount of months to take away, may be negative

Returns:

the new period minus the specified number of months

Throws:

java.lang.ArithmeticException - if the result overflows an int

minus

public Months minus(Months months)

Returns a new instance with the specified number of months taken away.

This instance is immutable and unaffected by this method call.

Parameters:

months - the amount of months to take away, may be negative, null means zero

Returns:

the new period minus the specified number of months

Throws:

java.lang.ArithmeticException - if the result overflows an int

multipliedBy

public Months multipliedBy(int scalar)

Returns a new instance with the months multiplied by the specified scalar.

This instance is immutable and unaffected by this method call.

Parameters:

scalar - the amount to multiply by, may be negative

Returns:

the new period multiplied by the specified scalar

Throws:

java.lang.ArithmeticException - if the result overflows an int

dividedBy

public Months dividedBy(int divisor)

Returns a new instance with the months divided by the specified divisor. The calculation uses integer division, thus 3 divided by 2 is 1.

This instance is immutable and unaffected by this method call.

Parameters:

divisor - the amount to divide by, may be negative

Returns:

the new period divided by the specified divisor

Throws:

java.lang.ArithmeticException - if the divisor is zero

negated

public Months negated()

Returns a new instance with the months value negated.

Returns:

the new period with a negated value

Throws:

java.lang.ArithmeticException - if the result overflows an int

isGreaterThan

public boolean isGreaterThan(Months other)

Is this months instance greater than the specified number of months.

Parameters:

other - the other period, null means zero

Returns:

true if this months instance is greater than the specified one

isLessThan

public boolean isLessThan(Months other)

Is this months instance less than the specified number of months.

Parameters:

other - the other period, null means zero

Returns:

true if this months instance is less than the specified one

toString

public java.lang.String toString()

Gets this instance as a String in the ISO8601 duration format.

For example, "P4M" represents 4 months.

Specified by:

toString in interface ReadablePeriod

Overrides:

toString in class java.lang.Object

Returns:

the value as an ISO8601 string