public
final
class
OptionalDouble
extends Object
java.lang.Object | |
↳ | java.util.OptionalDouble |
A container object which may or may not contain a double
value.
If a value is present, isPresent()
will return true
and
getAsDouble()
will return the value.
Additional methods that depend on the presence or absence of a contained
value are provided, such as orElse()
(return a default value if value not present) and
ifPresent()
(execute a block
of code if the value is present).
Public methods | |
---|---|
static
OptionalDouble
|
empty()
Returns an empty |
boolean
|
equals(Object obj)
Indicates whether some other object is "equal to" this OptionalDouble. |
double
|
getAsDouble()
If a value is present in this |
int
|
hashCode()
Returns the hash code value of the present value, if any, or 0 (zero) if no value is present. |
void
|
ifPresent(DoubleConsumer consumer)
Have the specified consumer accept the value if a value is present, otherwise do nothing. |
boolean
|
isPresent()
Return |
static
OptionalDouble
|
of(double value)
Return an |
double
|
orElse(double other)
Return the value if present, otherwise return |
double
|
orElseGet(DoubleSupplier other)
Return the value if present, otherwise invoke |
<X extends Throwable>
double
|
orElseThrow(Supplier<X> exceptionSupplier)
Return the contained value, if present, otherwise throw an exception to be created by the provided supplier. |
String
|
toString()
Returns a string representation of the object. Returns a non-empty string representation of this object suitable for debugging. |
Inherited methods | |
---|---|
From
class
java.lang.Object
|
OptionalDouble empty ()
Returns an empty OptionalDouble
instance. No value is present for this
OptionalDouble.
==
against instances returned by
Option.empty()
. There is no guarantee that it is a singleton.
Instead, use isPresent()
.Returns | |
---|---|
OptionalDouble |
an empty OptionalDouble .
|
boolean equals (Object obj)
Indicates whether some other object is "equal to" this OptionalDouble. The other object is considered equal if:
OptionalDouble
and;
Double.compare() == 0
.
Parameters | |
---|---|
obj |
Object :
an object to be tested for equality |
Returns | |
---|---|
boolean |
{code true} if the other object is "equal to" this object
otherwise false
|
double getAsDouble ()
If a value is present in this OptionalDouble
, returns the value,
otherwise throws NoSuchElementException
.
Returns | |
---|---|
double |
the value held by this OptionalDouble |
Throws | |
---|---|
NoSuchElementException |
if there is no value present |
See also:
int hashCode ()
Returns the hash code value of the present value, if any, or 0 (zero) if no value is present.
Returns | |
---|---|
int |
hash code value of the present value or 0 if no value is present |
void ifPresent (DoubleConsumer consumer)
Have the specified consumer accept the value if a value is present, otherwise do nothing.
Parameters | |
---|---|
consumer |
DoubleConsumer :
block to be executed if a value is present |
Throws | |
---|---|
NullPointerException |
if value is present and consumer is
null
|
boolean isPresent ()
Return true
if there is a value present, otherwise false
.
Returns | |
---|---|
boolean |
true if there is a value present, otherwise false
|
OptionalDouble of (double value)
Return an OptionalDouble
with the specified value present.
Parameters | |
---|---|
value |
double :
the value to be present |
Returns | |
---|---|
OptionalDouble |
an OptionalDouble with the value present
|
double orElse (double other)
Return the value if present, otherwise return other
.
Parameters | |
---|---|
other |
double :
the value to be returned if there is no value present |
Returns | |
---|---|
double |
the value, if present, otherwise other
|
double orElseGet (DoubleSupplier other)
Return the value if present, otherwise invoke other
and return
the result of that invocation.
Parameters | |
---|---|
other |
DoubleSupplier :
a DoubleSupplier whose result is returned if no value
is present |
Returns | |
---|---|
double |
the value if present otherwise the result of other.getAsDouble() |
Throws | |
---|---|
NullPointerException |
if value is not present and other is
null
|
double orElseThrow (Supplier<X> exceptionSupplier)
Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.
IllegalStateException::new
Parameters | |
---|---|
exceptionSupplier |
Supplier :
The supplier which will return the exception to
be thrown |
Returns | |
---|---|
double |
the present value |
Throws | |
---|---|
|
if there is no value present |
NullPointerException |
if no value is present and
exceptionSupplier is null
|
Throwable |
String toString ()
Returns a string representation of the object. In general, the
toString
method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString
method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@
', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
Returns a non-empty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.getClass().getName() + '@' + Integer.toHexString(hashCode())
Returns | |
---|---|
String |
the string representation of this instance |