class:OptionalDouble [NONE]

public final class OptionalDouble
extends Object

A container object which may or may not contain a double value. If a value is present, isPresent() returns true. If no value is present, the object is considered empty and isPresent() returns false.

Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (returns a default value if no value is present) and ifPresent() (performs an action if a 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.

API Note:: OptionalDouble is primarily intended for use as a method return type where there is a clear need to represent "no result." A variable whose type is OptionalDouble should never itself be null; it should always point to an OptionalDouble instance.
Since:: 1.8

method:empty() [NONE]

empty

public static 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 OptionalDouble.empty(). There is no guarantee that it is a singleton. Instead, use isPresent().
Returns:: an empty OptionalDouble.

method:of(double) [NONE]

of

public static OptionalDouble of?(double value)

Returns an OptionalDouble describing the given value.

Parameters:: value - the value to describe
Returns:: an OptionalDouble with the value present

method:getAsDouble() [NONE]

getAsDouble

public double getAsDouble()

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

API Note:: The preferred alternative to this method is orElseThrow().
Returns:: the value described by this OptionalDouble
Throws:: NoSuchElementException - if no value is present

method:isPresent() [NONE]

isPresent

public boolean isPresent()

If a value is present, returns true, otherwise false.

Returns:: true if a value is present, otherwise false

method:isEmpty() [NONE]

isEmpty

public boolean isEmpty()

If a value is not present, returns true, otherwise false.

Returns:: true if a value is not present, otherwise false
Since:: 11

method:ifPresent(java.util.function.DoubleConsumer) [NONE]

ifPresent

public void ifPresent?(DoubleConsumer action)

If a value is present, performs the given action with the value, otherwise does nothing.

Parameters:: action - the action to be performed, if a value is present
Throws:: NullPointerException - if value is present and the given action is null

method:ifPresentOrElse(java.util.function.DoubleConsumer,java.lang.Runnable) [NONE]

ifPresentOrElse

public void ifPresentOrElse?(DoubleConsumer action, Runnable emptyAction)

If a value is present, performs the given action with the value, otherwise performs the given empty-based action.

Parameters:: action - the action to be performed, if a value is present; emptyAction - the empty-based action to be performed, if no value is present
Throws:: NullPointerException - if a value is present and the given action is null, or no value is present and the given empty-based action is null.
Since:: 9

method:stream() [NONE]

stream

public DoubleStream stream()

If a value is present, returns a sequential DoubleStream containing only that value, otherwise returns an empty DoubleStream.

API Note:

This method can be used to transform a Stream of optional doubles to a DoubleStream of present doubles:


     Stream<OptionalDouble> os = ..
     DoubleStream s = os.flatMapToDouble(OptionalDouble::stream)

Returns:

the optional value as a DoubleStream

Since:

method:orElse(double) [NONE]

orElse

public double orElse?(double other)

If a value is present, returns the value, otherwise returns other.

Parameters:: other - the value to be returned, if no value is present
Returns:: the value, if present, otherwise other

method:orElseGet(java.util.function.DoubleSupplier) [NONE]

orElseGet

public double orElseGet?(DoubleSupplier supplier)

If a value is present, returns the value, otherwise returns the result produced by the supplying function.

Parameters:: supplier - the supplying function that produces a value to be returned
Returns:: the value, if present, otherwise the result produced by the supplying function
Throws:: NullPointerException - if no value is present and the supplying function is null

method:orElseThrow() [NONE]

orElseThrow

public double orElseThrow()

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

Returns:: the value described by this OptionalDouble
Throws:: NoSuchElementException - if no value is present
Since:: 10

method:orElseThrow(java.util.function.Supplier) [CHANGED]

orElseThrow

public <X extends Throwable> double orElseThrow?(Supplier<? extends X> exceptionSupplier) throws X extends Throwable

If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function.

API Note:: A method reference to the exception constructor with an empty argument list can be used as the supplier. For example, IllegalStateException::new
Type Parameters:: X - Type of the exception to be thrown
Parameters:: exceptionSupplier - the supplying function that produces an exception to be thrown
Returns:: the value, if present
Throws:: X - if no value is present; NullPointerException - if no value is present and the exception supplying function is null

X extends Throwable

orElseThrow

public <X extends Throwable> double orElseThrow?(Supplier<? extends X> exceptionSupplier) throws X extends Throwable

If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function.

API Note:: A method reference to the exception constructor with an empty argument list can be used as the supplier. For example, IllegalStateException::new
Type Parameters:: X - Type of the exception to be thrown
Parameters:: exceptionSupplier - the supplying function that produces an exception to be thrown
Returns:: the value, if present
Throws:: X - if no value is present; NullPointerException - if no value is present and the exception supplying function is null; X extends Throwable

orElseThrow

public <X extends Throwable> double orElseThrow?(Supplier<? extends X> exceptionSupplier) throws X extends Throwable

If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function.

API Note:: A method reference to the exception constructor with an empty argument list can be used as the supplier. For example, IllegalStateException::new
Type Parameters:: X - Type of the exception to be thrown
Parameters:: exceptionSupplier - the supplying function that produces an exception to be thrown
Returns:: the value, if present
Throws:: X - if no value is present; NullPointerException - if no value is present and the exception supplying function is null

method:equals(java.lang.Object) [NONE]

equals

public 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 .

Overrides:: equals in class Object
Parameters:: obj - an object to be tested for equality
Returns:: true if the other object is "equal to" this object otherwise false
See Also:: Object.hashCode(), HashMap

method:hashCode() [NONE]

hashCode

public int hashCode()

Returns the hash code of the value, if present, otherwise 0 (zero) if no value is present.

Overrides:: hashCode in class Object
Returns:: hash code value of the present value or 0 if no value is present
See Also:: Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

method:toString() [NONE]

toString

public String toString()

Returns a non-empty string representation of this OptionalDouble suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.

Overrides:: toString in class Object
Implementation Requirements:: If a value is present the result must include its string representation in the result. Empty and present OptionalDoubles must be unambiguously differentiable.
Returns:: the string representation of this instance