Era
public
interface
Era
implements
TemporalAccessor,
TemporalAdjuster
| java.time.chrono.Era |
An era of the time-line.
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.
Summary
Public methods | |
|---|---|
default
Temporal
|
adjustInto(Temporal temporal)
Adjusts the specified temporal object to have the same era as this object. |
default
int
|
get(TemporalField field)
Gets the value of the specified field from this era as an |
default
String
|
getDisplayName(TextStyle style, Locale locale)
Gets the textual representation of this era. |
default
long
|
getLong(TemporalField field)
Gets the value of the specified field from this era as a |
abstract
int
|
getValue()
Gets the numeric value associated with the era as defined by the chronology. |
default
boolean
|
isSupported(TemporalField field)
Checks if the specified field is supported. |
default
<R>
R
|
query(TemporalQuery<R> query)
Queries this era using the specified query. |
default
ValueRange
|
range(TemporalField field)
Gets the range of valid values for the specified field. |
Inherited methods | |
|---|---|
Public methods
adjustInto
public Temporal adjustInto (Temporal temporal)
Adjusts the specified temporal object to have the same era as this object.
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#with(TemporalField, long)
passing ChronoField#ERA as the field.
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 = thisEra.adjustInto(temporal); temporal = temporal.with(thisEra);
This instance is immutable and unaffected by this method call.
| Parameters | |
|---|---|
temporal |
Temporal: the target object to be adjusted, not null |
| Returns | |
|---|---|
Temporal |
the adjusted object, not null |
| Throws | |
|---|---|
DateTimeException |
if unable to make the adjustment |
ArithmeticException |
if numeric overflow occurs |
get
public int get (TemporalField field)
Gets the value of the specified field from this era as an int.
This queries this era for the value of 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.
| Parameters | |
|---|---|
field |
TemporalField: the field to get, not null |
| Returns | |
|---|---|
int |
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 |
getDisplayName
public String getDisplayName (TextStyle style, Locale locale)
Gets the textual representation of this era.
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.
API Note:
- This default implementation is suitable for most implementations.
| Parameters | |
|---|---|
style |
TextStyle: the style of the text required, not null |
locale |
Locale: the locale to use, not null |
| Returns | |
|---|---|
String |
the text value of the era, not null |
getLong
public long getLong (TemporalField field)
Gets the value of the specified field from this era as a long.
This queries this era for the value of 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.
| Parameters | |
|---|---|
field |
TemporalField: the field to get, not null |
| Returns | |
|---|---|
long |
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 |
getValue
public abstract int getValue ()
Gets the numeric value associated with the era as defined by the chronology. Each chronology defines the predefined Eras and methods to list the Eras of the chronology.
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:
- The era in use at the epoch 1970-01-01 (ISO) has the value 1.
- Later eras have sequentially higher values.
- Earlier eras have sequentially lower values, which may be negative.
| Returns | |
|---|---|
int |
the numeric era value |
isSupported
public boolean isSupported (TemporalField field)
Checks if the specified field is supported.
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.
| Parameters | |
|---|---|
field |
TemporalField: the field to check, null returns false |
| Returns | |
|---|---|
boolean |
true if the field is supported on this era, false if not |
query
public R query (TemporalQuery<R> query)
Queries this era using the specified 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#queryFrom(TemporalAccessor) method on the
specified query passing this as the argument.
| Parameters | |
|---|---|
query |
TemporalQuery: the query to invoke, not null |
| Returns | |
|---|---|
R |
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) |
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 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.
| Parameters | |
|---|---|
field |
TemporalField: the field to query the range for, not null |
| Returns | |
|---|---|
ValueRange |
the range of valid values for the field, not null |
| Throws | |
|---|---|
DateTimeException |
if the range for the field cannot be obtained |
UnsupportedTemporalTypeException |
if the unit is not supported |