Package org.joda.time

Interface ReadablePeriod

All Known Subinterfaces:

ReadWritablePeriod

All Known Implementing Classes:

AbstractPeriod, BasePeriod, BaseSingleFieldPeriod, Days, Hours, Minutes, Months, MutablePeriod, Period, Seconds, Weeks, Years

public interface ReadablePeriod

Defines a time period specified in terms of individual duration fields such as years and days.

The implementation of this interface may be mutable or immutable. This interface only gives access to retrieve data, never to change it.

Periods are split up into multiple fields, for example days and seconds. Implementations are not required to evenly distribute the values across the fields. The value for each field may be positive or negative.

When a time period is added to an instant, the effect is to add each field in turn. For example, a time period could be defined as 3 months, 2 days and -1 hours. In most circumstances this would be the same as 3 months, 1 day, and 23 hours. However, when adding across a daylight savings boundary, a day may be 23 or 25 hours long. Thus, the time period is always added field by field to the datetime.

Periods are independent of chronology, and can only be treated as durations when paired with a time via an interval.

Since:

1.0

Author:

Brian S O'Neill, Stephen Colebourne

See Also:

ReadableDuration, ReadableInterval

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object readablePeriod)	Compares this object with the specified object for equality based on the value and type of each supported field.
int	get(DurationFieldType field)	Gets the value of one of the fields.
DurationFieldType	getFieldType(int index)	Gets the field type at the specified index.
PeriodType	getPeriodType()	Gets the period type that defines which fields are included in the period.
int	getValue(int index)	Gets the value at the specified index.
int	hashCode()	Gets a hash code for the period that is compatible with the equals method.
boolean	isSupported(DurationFieldType field)	Checks whether the field type specified is supported by this period.
int	size()	Gets the number of fields that this period supports.
MutablePeriod	toMutablePeriod()	Get this object as a MutablePeriod.
Period	toPeriod()	Get this period as an immutable Period object.
java.lang.String	toString()	Gets the value as a String in the style of the ISO8601 duration format.

Method Detail

getPeriodType

PeriodType getPeriodType()

Gets the period type that defines which fields are included in the period.

Returns:

the period type

size

int size()

Gets the number of fields that this period supports.

Returns:

the number of fields supported

getFieldType

DurationFieldType getFieldType(int index)

Gets the field type at the specified index.

Parameters:

index - the index to retrieve

Returns:

the field at the specified index

Throws:

java.lang.IndexOutOfBoundsException - if the index is invalid

getValue

int getValue(int index)

Gets the value at the specified index.

Parameters:

index - the index to retrieve

Returns:

the value of the field at the specified index

Throws:

java.lang.IndexOutOfBoundsException - if the index is invalid

get

int get(DurationFieldType field)

Gets the value of one of the fields.

If the field type specified is not supported by the period then zero is returned.

Parameters:

field - the field type to query, null returns zero

Returns:

the value of that field, zero if field not supported

isSupported

boolean isSupported(DurationFieldType field)

Checks whether the field type specified is supported by this period.

Parameters:

field - the field to check, may be null which returns false

Returns:

true if the field is supported

toPeriod

Period toPeriod()

Get this period as an immutable Period object.

This will either typecast this instance, or create a new Period.

Returns:

a Duration using the same field set and values

toMutablePeriod

MutablePeriod toMutablePeriod()

Get this object as a MutablePeriod.

This will always return a new MutablePeriod with the same fields.

Returns:

a MutablePeriod using the same field set and values

equals

boolean equals(java.lang.Object readablePeriod)

Compares this object with the specified object for equality based on the value and type of each supported field. All ReadablePeriod instances are accepted.

Note that a period of 1 day is not equal to a period of 24 hours, nor is 1 hour equal to 60 minutes. Only periods with the same amount in each field are equal.

This is because periods represent an abstracted definition of a time period (eg. a day may not actually be 24 hours, it might be 23 or 25 at daylight savings boundary).

To compare the actual duration of two periods, convert both to Durations, an operation that emphasises that the result may differ according to the date you choose.

Overrides:

equals in class java.lang.Object

Parameters:

readablePeriod - a readable period to check against

Returns:

true if all the field values and types are equal, false if not or the period is null or of an incorrect type

hashCode

int hashCode()

Gets a hash code for the period that is compatible with the equals method. The hashcode is calculated as follows:

  int total = 17;
  for (int i = 0; i < fields.length; i++) {
      total = 27 * total + getValue(i);
      total = 27 * total + getFieldType(i).hashCode();
  }
  return total;
 

Overrides:

hashCode in class java.lang.Object

Returns:

a hash code

toString

java.lang.String toString()

Gets the value as a String in the style of the ISO8601 duration format. Technically, the output can breach the ISO specification as weeks may be included.

For example, "PT6H3M5S" represents 6 hours, 3 minutes, 5 seconds.

Overrides:

toString in class java.lang.Object

Returns:

the value as an ISO8601 style string