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OptionalLong

public final class OptionalLong
extends Object

java.lang.Object
   ↳ java.util.OptionalLong


A container object which may or may not contain a long value. If a value is present, isPresent() will return true and getAsLong() 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 OptionalLong empty()

Returns an empty OptionalLong instance.

boolean equals(Object obj)

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

long getAsLong()

If a value is present in this OptionalLong, 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(LongConsumer 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 OptionalLong of(long value)

Return an OptionalLong with the specified value present.

long orElse(long other)

Return the value if present, otherwise return other.

long orElseGet(LongSupplier other)

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

<X extends Throwable> long 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
OptionalLong empty ()

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

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
OptionalLong an empty OptionalLong.

equals

added in API level 24
boolean equals (Object obj)

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

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

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

getAsLong

added in API level 24
long getAsLong ()

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

Returns
long the value held by this OptionalLong

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 (LongConsumer consumer)

Have the specified consumer accept the value if a value is present, otherwise do nothing.

Parameters
consumer LongConsumer: 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
OptionalLong of (long value)

Return an OptionalLong with the specified value present.

Parameters
value long: the value to be present

Returns
OptionalLong an OptionalLong with the value present

orElse

added in API level 24
long orElse (long other)

Return the value if present, otherwise return other.

Parameters
other long: the value to be returned if there is no value present

Returns
long the value, if present, otherwise other

orElseGet

added in API level 24
long orElseGet (LongSupplier other)

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

Parameters
other LongSupplier: a LongSupplier whose result is returned if no value is present

Returns
long the value if present otherwise the result of other.getAsLong()

Throws
NullPointerException if value is not present and other is null

orElseThrow

added in API level 24
long 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
long 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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