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Added in API level 24

OptionalDouble

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).

Summary

Public methods

static OptionalDouble empty()

Returns an empty OptionalDouble instance.

boolean equals(Object obj)

Indicates whether some other object is "equal to" this OptionalDouble.

double getAsDouble()

If a value is present in this OptionalDouble, returns the value, otherwise throws NoSuchElementException.

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 true if there is a value present, otherwise false.

static OptionalDouble of(double value)

Return an OptionalDouble with the specified value present.

double orElse(double other)

Return the value if present, otherwise return other.

double orElseGet(DoubleSupplier other)

Return the value if present, otherwise invoke other and return the result of that invocation.

<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

Public methods

empty

Added in API level 24
OptionalDouble empty ()

Returns an empty OptionalDouble instance. No value is present for this OptionalDouble.

API Note:
  • Though it may be tempting to do so, avoid testing if an object is empty by comparing with == against instances returned by Option.empty(). There is no guarantee that it is a singleton. Instead, use isPresent().
Returns
OptionalDouble an empty OptionalDouble.

equals

Added in API level 24
boolean equals (Object obj)

Indicates whether some other object is "equal to" this OptionalDouble. The other object is considered equal if:

  • it is also an OptionalDouble and;
  • both instances have no value present or;
  • the present values are "equal to" each other via 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

getAsDouble

Added in API level 24
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:

hashCode

Added in API level 24
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

ifPresent

Added in API level 24
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

isPresent

Added in API level 24
boolean isPresent ()

Return true if there is a value present, otherwise false.

Returns
boolean true if there is a value present, otherwise false

of

Added in API level 24
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

orElse

Added in API level 24
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

orElseGet

Added in API level 24
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

orElseThrow

Added in API level 24
double orElseThrow (Supplier<X> exceptionSupplier)

Return the contained value, if present, otherwise throw an exception to be created by the provided supplier.

API Note:
  • A method reference to the exception constructor with an empty argument list can be used as the supplier. For example, 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

toString

Added in API level 24
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.

Implementation Requirements:
  • If a value is present the result must include its string representation in the result. Empty and present instances must be unambiguously differentiable.
Returns
String the string representation of this instance

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