Optional Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
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
- 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
| Name | Description |
|---|---|
| Class |
Returns the runtime class of this |
| Handle |
The handle to the underlying Android instance. (Inherited from Object) |
| IsEmpty |
If a value is not present, returns |
| IsPresent |
If a value is present, returns |
| JniIdentityHashCode |
Gets the identity hash code assigned to this Java peer by the interop runtime. (Inherited from Object) |
| JniPeerMembers | |
| PeerReference |
Gets the JNI object reference for this Java peer. (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
| Name | Description |
|---|---|
| Clone() |
Creates and returns a copy of this object. (Inherited from Object) |
| Dispose() |
Releases the resources held by this Java peer. (Inherited from Object) |
| Dispose(Boolean) |
Releases the resources held by this Java peer. (Inherited from Object) |
| Empty() |
Returns an empty |
| 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 |
| FlatMap(IFunction) |
If a value is present, returns the result of applying the given
|
| Get() |
If a value is present, returns the value, otherwise throws
|
| 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 |
| 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 |
| OfNullable(Object) |
Returns an |
| Or(ISupplier) |
If a value is present, returns an |
| OrElse(Object) |
If a value is present, returns the value, otherwise returns
|
| 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
|
| 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>() |
Creates a managed array from this Java array wrapper. (Inherited from Object) |
| ToString() |
Returns a string representation of the object. (Inherited from Object) |
| UnregisterFromRuntime() |
Unregisters this Java peer from the interop runtime. (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
| Name | Description |
|---|---|
| IJavaPeerable.Disposed() |
Notifies the interop runtime that this managed peer has been disposed. (Inherited from Object) |
| IJavaPeerable.DisposeUnlessReferenced() |
Releases this Java peer unless it is retained by another managed reference. (Inherited from Object) |
| IJavaPeerable.Finalized() |
Notifies the interop runtime that this managed peer has been finalized. (Inherited from Object) |
| IJavaPeerable.JniManagedPeerState |
Gets the state that describes the relationship between this managed peer and its JNI reference. (Inherited from Object) |
| IJavaPeerable.SetJniIdentityHashCode(Int32) |
Sets the interop identity hash code for this Java peer. (Inherited from Object) |
| IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates) |
Sets the managed and JNI peer state for this Java peer. (Inherited from Object) |
| IJavaPeerable.SetPeerReference(JniObjectReference) |
Sets the JNI object reference used by this managed peer. (Inherited from Object) |
Extension Methods
| Name | Description |
|---|---|
| GetJniTypeName(IJavaPeerable) |
Gets the JNI name of the type of the instance |
| JavaAs<TResult>(IJavaPeerable) |
Try to coerce |
| JavaCast<TResult>(IJavaObject) |
Performs an Android runtime-checked type conversion. |
| JavaCast<TResult>(IJavaObject) | |
| TryJavaCast<TResult>(IJavaPeerable, TResult) |
Try to coerce |