org.joda.time

Interface ReadablePeriod

Known Subinterfaces:
ReadWritablePeriod
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.

Authors:
Brian S O'Neill
Stephen Colebourne
Since:
1.0
See Also:
ReadableDuration, ReadableInterval

Method Summary

boolean
equals(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.
String
toString()
Gets the value as a String in the style of the ISO8601 duration format.

Method Details

equals

public boolean equals(Object readablePeriod)
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

get

public 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

getFieldType

public 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

getPeriodType

public PeriodType getPeriodType()
Gets the period type that defines which fields are included in the period.
Returns:
the period type

getValue

public 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

hashCode

public 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 <32fields.length; i++) {
      total = 27 * total + getValue(i);
      total = 27 * total + getFieldType(i).hashCode();
  }
  return total;
 
Returns:
a hash code

isSupported

public 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

size

public int size()
Gets the number of fields that this period supports.
Returns:
the number of fields supported

toMutablePeriod

public 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

toPeriod

public 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

toString

public 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.

Returns:
the value as an ISO8601 style string

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