public final class OptionalDouble extends Object
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).
This is a value-based class; use of identity-sensitive operations (including reference equality (==
), identity hash code, or synchronization) on instances of OptionalDouble
may have unpredictable results and should be avoided.
public static 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()
.OptionalDouble
.public static OptionalDouble of(double value)
Return an OptionalDouble
with the specified value present.
value
- the value to be presentOptionalDouble
with the value presentpublic double getAsDouble()
If a value is present in this OptionalDouble
, returns the value, otherwise throws NoSuchElementException
.
OptionalDouble
NoSuchElementException
- if there is no value presentisPresent()
public boolean isPresent()
Return true
if there is a value present, otherwise false
.
true
if there is a value present, otherwise false
public void ifPresent(DoubleConsumer consumer)
Have the specified consumer accept the value if a value is present, otherwise do nothing.
consumer
- block to be executed if a value is presentNullPointerException
- if value is present and consumer
is nullpublic double orElse(double other)
Return the value if present, otherwise return other
.
other
- the value to be returned if there is no value presentother
public double orElseGet(DoubleSupplier other)
Return the value if present, otherwise invoke other
and return the result of that invocation.
other
- a DoubleSupplier
whose result is returned if no value is presentother.getAsDouble()
NullPointerException
- if value is not present and other
is nullpublic <X extends Throwable> double orElseThrow(Supplier<X> exceptionSupplier) throws X extends Throwable
Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.
IllegalStateException::new
X
- Type of the exception to be thrownexceptionSupplier
- The supplier which will return the exception to be thrownX
- if there is no value presentNullPointerException
- if no value is present and exceptionSupplier
is nullX extends Throwable
public 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
. equals
in class Object
obj
- an object to be tested for equalityfalse
Object.hashCode()
, HashMap
public int hashCode()
Returns the hash code value of the present value, if any, or 0 (zero) if no value is present.
hashCode
in class Object
Object.equals(java.lang.Object)
, System.identityHashCode(java.lang.Object)
public 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:
getClass().getName() + '@' + Integer.toHexString(hashCode())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.
toString
in class Object
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Documentation extracted from Debian's OpenJDK Development Kit package.
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