public interface Era extends TemporalAccessor, TemporalAdjuster
Most calendar systems have a single epoch dividing the time-line into two eras. However, some calendar systems, have multiple eras, such as one for the reign of each leader. In all cases, the era is conceptually the largest division of the time-line. Each chronology defines the Era's that are known Eras and a Chronology.eras to get the valid eras.
For example, the Thai Buddhist calendar system divides time into two eras, before and after a single date. By contrast, the Japanese calendar system has one era for the reign of each Emperor.
Instances of Era may be compared using the == operator.
| Modifier and Type | Method and Description |
|---|---|
default Temporal |
adjustInto(Temporal
Adjusts the specified temporal object to have the same era as this object.
|
default int |
get(TemporalField
Gets the value of the specified field from this era as an
int.
|
default String |
getDisplayName(TextStyle
Gets the textual representation of this era.
|
default long |
getLong(TemporalField
Gets the value of the specified field from this era as a
long.
|
int |
getValue()
Gets the numeric value associated with the era as defined by the chronology.
|
default boolean |
isSupported(TemporalField
Checks if the specified field is supported.
|
default <R> R |
query(TemporalQuery
Queries this era using the specified query.
|
default ValueRange |
range(TemporalField
Gets the range of valid values for the specified field.
|
int getValue()
All fields, including eras, have an associated numeric value. The meaning of the numeric value for era is determined by the chronology according to these principles:
default boolean isSupported(TemporalFieldfield)
This checks if this era can be queried for the specified field. If false, then calling the range and get methods will throw an exception.
If the field is a ChronoField then the query is implemented here. The ERA field returns true. 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.
isSupported in interface
TemporalAccessor
field - the field to check, null returns false
default ValueRangerange(TemporalField field)
The range object expresses the minimum and maximum valid values for a field. This era 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 ERA field returns the range. 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.
The default implementation must return a range for ERA from zero to one, suitable for two era calendar systems such as ISO.
range in interface
TemporalAccessor
field - the field to query the range for, not null
DateTimeException - if the range for the field cannot be obtained
UnsupportedTemporalTypeException - if the unit is not supported
default int get(TemporalFieldfield)
int.
This queries this era 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 ERA field returns the value of the era. 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.
get in interface
TemporalAccessor
field - the field to get, not null
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
default long getLong(TemporalFieldfield)
long.
This queries this era 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 ERA field returns the value of the era. 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.
getLong in interface
TemporalAccessor
field - the field to get, not null
DateTimeException - if a value for the field cannot be obtained
UnsupportedTemporalTypeException - if the field is not supported
ArithmeticException - if numeric overflow occurs
default <R> R query(TemporalQuery<R> query)
This queries this era 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 method on the specified query passing this as the argument.
query in interface
TemporalAccessor
R - the type of the result
query - the query to invoke, not null
DateTimeException - if unable to query (defined by the query)
ArithmeticException - if numeric overflow occurs (defined by the query)
default TemporaladjustInto(Temporal temporal)
This returns a temporal object of the same observable type as the input with the era changed to be the same as this.
The adjustment is equivalent to using Temporal passing ChronoField as the field.
In most cases, it is clearer to reverse the calling pattern by using Temporal:
// these two lines are equivalent, but the second approach is recommended temporal = thisEra.adjustInto(temporal); temporal = temporal.with(thisEra);
This instance is immutable and unaffected by this method call.
adjustInto in interface
TemporalAdjuster
temporal - the target object to be adjusted, not null
DateTimeException - if unable to make the adjustment
ArithmeticException - if numeric overflow occurs
default StringgetDisplayName(TextStyle style, Locale locale)
This returns the textual name used to identify the era, 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 the numeric value is returned.
This default implementation is suitable for all implementations.
style - the style of the text required, not null
locale - the locale to use, not null