OptionalInt
public
final
class
OptionalInt
extends Object
java.lang.Object | |
↳ | java.util.OptionalInt |
A container object which may or may not contain an int
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; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.
Summary
Public methods | |
---|---|
static
OptionalInt
|
empty()
Returns an empty |
boolean
|
equals(Object obj)
Indicates whether some other object is "equal to" this
|
int
|
getAsInt()
If a value is present, returns the value, otherwise throws
|
int
|
hashCode()
Returns the hash code of the value, if present, otherwise |
void
|
ifPresent(IntConsumer action)
If a value is present, performs the given action with the value, otherwise does nothing. |
void
|
ifPresentOrElse(IntConsumer action, Runnable emptyAction)
If a value is present, performs the given action with the value, otherwise performs the given empty-based action. |
boolean
|
isEmpty()
If a value is not present, returns |
boolean
|
isPresent()
If a value is present, returns |
static
OptionalInt
|
of(int value)
Returns an |
int
|
orElse(int other)
If a value is present, returns the value, otherwise returns
|
int
|
orElseGet(IntSupplier supplier)
If a value is present, returns the value, otherwise returns the result produced by the supplying function. |
<X extends Throwable>
int
|
orElseThrow(Supplier<? extends X> exceptionSupplier)
If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function. |
int
|
orElseThrow()
If a value is present, returns the value, otherwise throws
|
IntStream
|
stream()
If a value is present, returns a sequential |
String
|
toString()
Returns a non-empty string representation of this |
Inherited methods | |
---|---|
Public methods
empty
public static OptionalInt empty ()
Returns an empty OptionalInt
instance. No value is present for
this OptionalInt
.
API Note:
- Though it may be tempting to do so, avoid testing if an object is empty
by comparing with
==
or!=
against instances returned byOptionalInt.empty()
. There is no guarantee that it is a singleton. Instead, useisEmpty()
orisPresent()
.
Returns | |
---|---|
OptionalInt |
an empty OptionalInt |
equals
public boolean equals (Object obj)
Indicates whether some other object is "equal to" this
OptionalInt
. The other object is considered equal if:
- it is also an
OptionalInt
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 |
true if the other object is "equal to" this object
otherwise false |
getAsInt
public int getAsInt ()
If a value is present, returns the value, otherwise throws
NoSuchElementException
.
API Note:
- The preferred alternative to this method is
orElseThrow()
.
Returns | |
---|---|
int |
the value described by this OptionalInt |
Throws | |
---|---|
NoSuchElementException |
if no value is present |
hashCode
public int hashCode ()
Returns the hash code of the value, if present, otherwise 0
(zero) if no value is present.
Returns | |
---|---|
int |
hash code value of the present value or 0 if no value is
present |
ifPresent
public void ifPresent (IntConsumer action)
If a value is present, performs the given action with the value, otherwise does nothing.
Parameters | |
---|---|
action |
IntConsumer : the action to be performed, if a value is present |
Throws | |
---|---|
NullPointerException |
if value is present and the given action is
null |
ifPresentOrElse
public void ifPresentOrElse (IntConsumer action, Runnable emptyAction)
If a value is present, performs the given action with the value, otherwise performs the given empty-based action.
Parameters | |
---|---|
action |
IntConsumer : the action to be performed, if a value is present |
emptyAction |
Runnable : 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 . |
isEmpty
public boolean isEmpty ()
If a value is not present, returns true
, otherwise
false
.
Returns | |
---|---|
boolean |
true if a value is not present, otherwise false |
isPresent
public boolean isPresent ()
If a value is present, returns true
, otherwise false
.
Returns | |
---|---|
boolean |
true if a value is present, otherwise false |
of
public static OptionalInt of (int value)
Returns an OptionalInt
describing the given value.
Parameters | |
---|---|
value |
int : the value to describe |
Returns | |
---|---|
OptionalInt |
an OptionalInt with the value present |
orElse
public int orElse (int other)
If a value is present, returns the value, otherwise returns
other
.
Parameters | |
---|---|
other |
int : the value to be returned, if no value is present |
Returns | |
---|---|
int |
the value, if present, otherwise other |
orElseGet
public int orElseGet (IntSupplier supplier)
If a value is present, returns the value, otherwise returns the result produced by the supplying function.
Parameters | |
---|---|
supplier |
IntSupplier : the supplying function that produces a value to be returned |
Returns | |
---|---|
int |
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 |
orElseThrow
public int orElseThrow (Supplier<? extends X> exceptionSupplier)
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
Parameters | |
---|---|
exceptionSupplier |
Supplier : the supplying function that produces an
exception to be thrown |
Returns | |
---|---|
int |
the value, if present |
Throws | |
---|---|
|
if no value is present |
NullPointerException |
if no value is present and the exception
supplying function is null |
Throwable |
orElseThrow
public int orElseThrow ()
If a value is present, returns the value, otherwise throws
NoSuchElementException
.
Returns | |
---|---|
int |
the value described by this OptionalInt |
Throws | |
---|---|
NoSuchElementException |
if no value is present |
stream
public IntStream stream ()
If a value is present, returns a sequential IntStream
containing
only that value, otherwise returns an empty IntStream
.
API Note:
- This method can be used to transform a
Stream
of optional integers to anIntStream
of present integers:Stream<OptionalInt> os = .. IntStream s = os.flatMapToInt(OptionalInt::stream)
Returns | |
---|---|
IntStream |
the optional value as an IntStream |
toString
public String toString ()
Returns a non-empty string representation of this OptionalInt
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
OptionalInt
s must be unambiguously differentiable.
Returns | |
---|---|
String |
the string representation of this instance |