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Optional Class

Definition

A container object which may or may not contain a non-null value.

[Android.Runtime.Register("java/util/Optional", ApiSince=24, DoNotGenerateAcw=true)]
[Java.Interop.JavaTypeParameters(new System.String[] { "T" })]
public sealed class Optional : Java.Lang.Object
[<Android.Runtime.Register("java/util/Optional", ApiSince=24, DoNotGenerateAcw=true)>]
[<Java.Interop.JavaTypeParameters(new System.String[] { "T" })>]
type Optional = class
    inherit Object
Inheritance
Optional
Attributes

Remarks

A container object which may or may not contain a non-null 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(Object) orElse() (returns a default value if no value is present) and #ifPresent(Consumer) ifPresent() (performs an action if a value is present).

<!--

This is a value-based class; programmers should treat instances that are #equals(Object) equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.-->

Added in 1.8.

Java documentation for java.util.Optional.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Properties

Class

Returns the runtime class of this Object.

(Inherited from Object)
Handle

The handle to the underlying Android instance.

(Inherited from Object)
IsEmpty

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

IsPresent

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

JniIdentityHashCode (Inherited from Object)
JniPeerMembers
PeerReference (Inherited from Object)
ThresholdClass

This API supports the Mono for Android infrastructure and is not intended to be used directly from your code.

(Inherited from Object)
ThresholdType

This API supports the Mono for Android infrastructure and is not intended to be used directly from your code.

(Inherited from Object)

Methods

Clone()

Creates and returns a copy of this object.

(Inherited from Object)
Dispose() (Inherited from Object)
Dispose(Boolean) (Inherited from Object)
Empty()

Returns an empty Optional instance.

Equals(Object)

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

(Inherited from Object)
Filter(IPredicate)

If a value is present, and the value matches the given predicate, returns an Optional describing the value, otherwise returns an empty Optional.

FlatMap(IFunction)

If a value is present, returns the result of applying the given Optional-bearing mapping function to the value, otherwise returns an empty Optional.

Get()

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

GetHashCode()

Returns a hash code value for the object.

(Inherited from Object)
IfPresent(IConsumer)

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

IfPresentOrElse(IConsumer, IRunnable)

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

JavaFinalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

(Inherited from Object)
Map(IFunction)

If a value is present, returns an Optional describing (as if by #ofNullable) the result of applying the given mapping function to the value, otherwise returns an empty Optional.

Notify()

Wakes up a single thread that is waiting on this object's monitor.

(Inherited from Object)
NotifyAll()

Wakes up all threads that are waiting on this object's monitor.

(Inherited from Object)
Of(Object)

Returns an Optional describing the given non-null value.

OfNullable(Object)

Returns an Optional describing the given value, if non-null, otherwise returns an empty Optional.

Or(ISupplier)

If a value is present, returns an Optional describing the value, otherwise returns an Optional produced by the supplying function.

OrElse(Object)

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

OrElseGet(ISupplier)

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

OrElseThrow()

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

OrElseThrow(ISupplier)

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

SetHandle(IntPtr, JniHandleOwnership)

Sets the Handle property.

(Inherited from Object)
ToArray<T>() (Inherited from Object)
ToString()

Returns a string representation of the object.

(Inherited from Object)
UnregisterFromRuntime() (Inherited from Object)
Wait()

Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>.

(Inherited from Object)
Wait(Int64, Int32)

Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed.

(Inherited from Object)
Wait(Int64)

Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed.

(Inherited from Object)

Explicit Interface Implementations

IJavaPeerable.Disposed() (Inherited from Object)
IJavaPeerable.DisposeUnlessReferenced() (Inherited from Object)
IJavaPeerable.Finalized() (Inherited from Object)
IJavaPeerable.JniManagedPeerState (Inherited from Object)
IJavaPeerable.SetJniIdentityHashCode(Int32) (Inherited from Object)
IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates) (Inherited from Object)
IJavaPeerable.SetPeerReference(JniObjectReference) (Inherited from Object)

Extension Methods

JavaCast<TResult>(IJavaObject)

Performs an Android runtime-checked type conversion.

JavaCast<TResult>(IJavaObject)
GetJniTypeName(IJavaPeerable)

Applies to