OptionalDouble | API reference | Android Developers (original) (raw)
class OptionalDouble
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()](#orElse%28kotlin.Double%29) (returns a default value if no value is present) and [ifPresent()](#ifPresent%28java.util.function.DoubleConsumer%29) (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 OptionalDouble! | empty() Returns an empty OptionalDouble instance. |
| Boolean | equals(other: Any?) Indicates whether some other object is "equal to" this OptionalDouble. |
| Double | getAsDouble() 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. |
| Unit | ifPresent(action: DoubleConsumer!) If a value is present, performs the given action with the value, otherwise does nothing. |
| Unit | ifPresentOrElse(action: DoubleConsumer!, emptyAction: Runnable!) 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 OptionalDouble! | of(value: Double) Returns an OptionalDouble describing the given value. |
| Double | orElse(other: Double) If a value is present, returns the value, otherwise returns other. |
| Double | orElseGet(supplier: DoubleSupplier!) If a value is present, returns the value, otherwise returns the result produced by the supplying function. |
| Double | orElseThrow() If a value is present, returns the value, otherwise throws NoSuchElementException. |
| Double | orElseThrow(exceptionSupplier: Supplier<out X>!) If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function. |
| DoubleStream! | stream() If a value is present, returns a sequential DoubleStream containing only that value, otherwise returns an empty DoubleStream. |
| String | toString() Returns a non-empty string representation of this OptionalDouble suitable for debugging. |
Public methods
empty
static fun empty(): OptionalDouble!
Returns an empty OptionalDouble instance. No value is present for this OptionalDouble.
| Return | |
|---|---|
| OptionalDouble! | an empty OptionalDouble. |
equals
fun equals(other: Any?): Boolean
Indicates whether some other object is "equal to" this OptionalDouble. The other object is considered equal if:
- it is also an
OptionalDoubleand; - both instances have no value present or;
- the present values are "equal to" each other via
Double.compare() == 0.
| Parameters | |
|---|---|
| obj | an object to be tested for equality |
| Return | |
|---|---|
| Boolean | true if the other object is "equal to" this object otherwise false |
getAsDouble
fun getAsDouble(): Double
If a value is present, returns the value, otherwise throws NoSuchElementException.
| Return | |
|---|---|
| Double | the value described by this OptionalDouble |
| Exceptions | |
|---|---|
| java.util.NoSuchElementException | if no value is present |
hashCode
fun hashCode(): Int
Returns the hash code of the value, if present, otherwise 0 (zero) if no value is present.
| Return | |
|---|---|
| Int | hash code value of the present value or 0 if no value is present |
ifPresent
fun ifPresent(action: DoubleConsumer!): Unit
If a value is present, performs the given action with the value, otherwise does nothing.
| Parameters | |
|---|---|
| action | DoubleConsumer!: the action to be performed, if a value is present |
| Exceptions | |
|---|---|
| java.lang.NullPointerException | if value is present and the given action is null |
ifPresentOrElse
fun ifPresentOrElse(
action: DoubleConsumer!,
emptyAction: Runnable!
): Unit
If a value is present, performs the given action with the value, otherwise performs the given empty-based action.
| Parameters | |
|---|---|
| action | DoubleConsumer!: the action to be performed, if a value is present |
| emptyAction | Runnable!: the empty-based action to be performed, if no value is present |
| Exceptions | |
|---|---|
| java.lang.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
fun isEmpty(): Boolean
If a value is not present, returns true, otherwise false.
| Return | |
|---|---|
| Boolean | true if a value is not present, otherwise false |
isPresent
fun isPresent(): Boolean
If a value is present, returns true, otherwise false.
| Return | |
|---|---|
| Boolean | true if a value is present, otherwise false |
of
static fun of(value: Double): OptionalDouble!
Returns an OptionalDouble describing the given value.
| Parameters | |
|---|---|
| value | Double: the value to describe |
| Return | |
|---|---|
| OptionalDouble! | an OptionalDouble with the value present |
orElse
fun orElse(other: Double): Double
If a value is present, returns the value, otherwise returns other.
| Parameters | |
|---|---|
| other | Double: the value to be returned, if no value is present |
| Return | |
|---|---|
| Double | the value, if present, otherwise other |
orElseGet
fun orElseGet(supplier: DoubleSupplier!): Double
If a value is present, returns the value, otherwise returns the result produced by the supplying function.
| Parameters | |
|---|---|
| supplier | DoubleSupplier!: the supplying function that produces a value to be returned |
| Return | |
|---|---|
| Double | the value, if present, otherwise the result produced by the supplying function |
| Exceptions | |
|---|---|
| java.lang.NullPointerException | if no value is present and the supplying function is null |
orElseThrow
fun orElseThrow(): Double
If a value is present, returns the value, otherwise throws NoSuchElementException.
| Return | |
|---|---|
| Double | the value described by this OptionalDouble |
| Exceptions | |
|---|---|
| java.util.NoSuchElementException | if no value is present |
orElseThrow
fun <X : Throwable!> orElseThrow(exceptionSupplier: Supplier!): Double
If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function.
| Parameters | |
|---|---|
| Type of the exception to be thrown | |
| exceptionSupplier | Supplier<out X>!: the supplying function that produces an exception to be thrown |
| Return | |
|---|---|
| Double | the value, if present |
| Exceptions | |
|---|---|
| X | if no value is present |
| java.lang.NullPointerException | if no value is present and the exception supplying function is null |
stream
fun stream(): DoubleStream!
If a value is present, returns a sequential [DoubleStream](/reference/kotlin/java/util/stream/DoubleStream) containing only that value, otherwise returns an empty DoubleStream.
| Return | |
|---|---|
| DoubleStream! | the optional value as a DoubleStream |
toString
fun toString(): String
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.
| Return | |
|---|---|
| String | the string representation of this instance |