public final class OptionalInt extends Object
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.
OptionalInt
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 OptionalInt
should never itself be null
; it should always point to an OptionalInt
instance.Modifier and Type | Method | Description |
---|---|---|
static OptionalInt |
empty() |
Returns an empty OptionalInt instance. |
boolean |
equals |
Indicates whether some other object is "equal to" this OptionalInt . |
int |
getAsInt() |
If a value is present, returns the value, otherwise throws NoSuchElementException . |
int |
hashCode() |
Returns the hash code of the value, if present, otherwise 0 (zero) if no value is present. |
void |
ifPresent |
If a value is present, performs the given action with the value, otherwise does nothing. |
void |
ifPresentOrElse |
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 true , otherwise false . |
boolean |
isPresent() |
If a value is present, returns true , otherwise false . |
static OptionalInt |
of |
Returns an OptionalInt describing the given value. |
int |
orElse |
If a value is present, returns the value, otherwise returns other . |
int |
orElseGet |
If a value is present, returns the value, otherwise returns the result produced by the supplying function. |
int |
orElseThrow() |
If a value is present, returns the value, otherwise throws NoSuchElementException . |
<X extends Throwable> |
orElseThrow |
If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function. |
IntStream |
stream() |
If a value is present, returns a sequential IntStream containing only that value, otherwise returns an empty IntStream . |
String |
toString() |
Returns a non-empty string representation of this OptionalInt suitable for debugging. |
public static OptionalInt empty()
OptionalInt
instance. No value is present for this OptionalInt
.==
or !=
against instances returned by OptionalInt.empty()
. There is no guarantee that it is a singleton. Instead, use isEmpty()
or isPresent()
.OptionalInt
public static OptionalInt of(int value)
OptionalInt
describing the given value.value
- the value to describeOptionalInt
with the value presentpublic int getAsInt()
NoSuchElementException
.orElseThrow()
.OptionalInt
NoSuchElementException
- if no value is presentpublic boolean isPresent()
true
, otherwise false
.true
if a value is present, otherwise false
public boolean isEmpty()
true
, otherwise false
.true
if a value is not present, otherwise false
public void ifPresent(IntConsumer action)
action
- the action to be performed, if a value is presentNullPointerException
- if value is present and the given action is null
public void ifPresentOrElse(IntConsumer action, Runnable emptyAction)
action
- the action to be performed, if a value is presentemptyAction
- the empty-based action to be performed, if no value is presentNullPointerException
- if a value is present and the given action is null
, or no value is present and the given empty-based action is null
.public IntStream stream()
IntStream
containing only that value, otherwise returns an empty IntStream
.Stream
of optional integers to an IntStream
of present integers:
Stream<OptionalInt> os = ..
IntStream s = os.flatMapToInt(OptionalInt::stream)
IntStream
public int orElse(int other)
other
.other
- the value to be returned, if no value is presentother
public int orElseGet(IntSupplier supplier)
supplier
- the supplying function that produces a value to be returnedNullPointerException
- if no value is present and the supplying function is null
public int orElseThrow()
NoSuchElementException
.OptionalInt
NoSuchElementException
- if no value is presentpublic <X extends Throwable> int orElseThrow(Supplier<? extends X> exceptionSupplier) throws X
IllegalStateException::new
X
- Type of the exception to be thrownexceptionSupplier
- the supplying function that produces an exception to be thrownX
- if no value is presentNullPointerException
- if no value is present and the exception supplying function is null
public boolean equals(Object obj)
OptionalInt
. The other object is considered equal if: OptionalInt
and; ==
. public int hashCode()
0
(zero) if no value is present.public String toString()
OptionalInt
suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions.
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/OptionalInt.html