IFuture Interface

Definition

Namespace:

Java.Util.Concurrent

Assembly:

Mono.Android.dll

A Future represents the result of an asynchronous computation.

[Android.Runtime.Register("java/util/concurrent/Future", "", "Java.Util.Concurrent.IFutureInvoker")]
[Java.Interop.JavaTypeParameters(new System.String[] { "V" })]
public interface IFuture : Android.Runtime.IJavaObject, IDisposable, Java.Interop.IJavaPeerable

[<Android.Runtime.Register("java/util/concurrent/Future", "", "Java.Util.Concurrent.IFutureInvoker")>]
[<Java.Interop.JavaTypeParameters(new System.String[] { "V" })>]
type IFuture = interface
    interface IJavaObject
    interface IDisposable
    interface IJavaPeerable

Derived

Java.Util.Concurrent.CompletableFuture

Java.Util.Concurrent.ForkJoinTask

Java.Util.Concurrent.FutureTask

Java.Util.Concurrent.IRunnableFuture

Java.Util.Concurrent.IRunnableScheduledFuture

Java.Util.Concurrent.IScheduledFuture

Attributes

RegisterAttribute JavaTypeParametersAttribute

Implements

IJavaObject IJavaPeerable IDisposable

Remarks

A Future represents the result of an asynchronous computation. Methods are provided to check if the computation is complete, to wait for its completion, and to retrieve the result of the computation. The result can only be retrieved using method get when the computation has completed, blocking if necessary until it is ready. Cancellation is performed by the cancel method. Additional methods are provided to determine if the task completed normally or was cancelled. Once a computation has completed, the computation cannot be cancelled. If you would like to use a Future for the sake of cancellability but not provide a usable result, you can declare types of the form Future<?> and return null as a result of the underlying task.

<b>Sample Usage</b> (Note that the following classes are all made-up.)

{@code
            interface ArchiveSearcher { String search(String target); }
            class App {
              ExecutorService executor = ...;
              ArchiveSearcher searcher = ...;
              void showSearch(String target) throws InterruptedException {
                Callable<String> task = () -> searcher.search(target);
                Future<String> future = executor.submit(task);
                displayOtherThings(); // do other things while searching
                try {
                  displayText(future.get()); // use future
                } catch (ExecutionException ex) { cleanup(); return; }
              }
            }}

The FutureTask class is an implementation of Future that implements Runnable, and so may be executed by an Executor. For example, the above construction with submit could be replaced by:

{@code
            FutureTask<String> future = new FutureTask<>(task);
            executor.execute(future);}

Memory consistency effects: Actions taken by the asynchronous computation <i>happen-before</i> actions following the corresponding Future.get() in another thread.

Added in 1.5.

Java documentation for java.util.concurrent.Future.

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

Handle	Gets the JNI value of the underlying Android object. (Inherited from IJavaObject)
IsCancelled	Returns true if this task was cancelled before it completed normally.
IsDone	Returns true if this task completed.
JniIdentityHashCode	Returns the value of java.lang.System.identityHashCode() for the wrapped instance. (Inherited from IJavaPeerable)
JniManagedPeerState	State of the managed peer. (Inherited from IJavaPeerable)
JniPeerMembers	Member access and invocation support. (Inherited from IJavaPeerable)
PeerReference	Returns a JniObjectReference of the wrapped Java object instance. (Inherited from IJavaPeerable)

Methods

Cancel(Boolean)	Attempts to cancel execution of this task.
Disposed()	Called when the instance has been disposed. (Inherited from IJavaPeerable)
DisposeUnlessReferenced()	If there are no outstanding references to this instance, then calls Dispose(); otherwise, does nothing. (Inherited from IJavaPeerable)
Finalized()	Called when the instance has been finalized. (Inherited from IJavaPeerable)
Get()	Waits if necessary for the computation to complete, and then retrieves its result.
Get(Int64, TimeUnit)	Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
SetJniIdentityHashCode(Int32)	Set the value returned by JniIdentityHashCode. (Inherited from IJavaPeerable)
SetJniManagedPeerState(JniManagedPeerStates)	(Inherited from IJavaPeerable)
SetPeerReference(JniObjectReference)	Set the value returned by PeerReference. (Inherited from IJavaPeerable)
UnregisterFromRuntime()	Unregister this instance so that the runtime will not return it from future Java.Interop.JniRuntime+JniValueManager.PeekValue invocations. (Inherited from IJavaPeerable)

Extension Methods

JavaCast<TResult>(IJavaObject)	Performs an Android runtime-checked type conversion.
JavaCast<TResult>(IJavaObject)
GetJniTypeName(IJavaPeerable)
GetAsync(IFuture, Int64, TimeUnit)
GetAsync(IFuture)