Package com.google.common.util.concurrent

Class ClosingFuture.Combiner4<V1 extends @Nullable Object,V2 extends @Nullable Object,V3 extends @Nullable Object,V4 extends @Nullable Object>

java.lang.Object

com.google.common.util.concurrent.ClosingFuture.Combiner

com.google.common.util.concurrent.ClosingFuture.Combiner4<V1,V2,V3,V4>

Type Parameters:

V1 - the type returned by the first future

V2 - the type returned by the second future

V3 - the type returned by the third future

V4 - the type returned by the fourth future

Enclosing class:

ClosingFuture<V>

public static final class ClosingFuture.Combiner4<V1 extends @Nullable Object,V2 extends @Nullable Object,V3 extends @Nullable Object,V4 extends @Nullable Object>
extends ClosingFuture.Combiner

A generic ClosingFuture.Combiner that lets you use a lambda or method reference to combine four ClosingFutures. Use ClosingFuture.whenAllSucceed(ClosingFuture, ClosingFuture, ClosingFuture, ClosingFuture) to start this combination.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ClosingFuture.Combiner4.AsyncClosingFunction4<V1 extends @Nullable Object,V2 extends @Nullable Object,V3 extends @Nullable Object,V4 extends @Nullable Object,U extends @Nullable Object>	A function that returns a ClosingFuture when applied to the values of the four futures passed to ClosingFuture.whenAllSucceed(ClosingFuture, ClosingFuture, ClosingFuture, ClosingFuture).
static interface	ClosingFuture.Combiner4.ClosingFunction4<V1 extends @Nullable Object,V2 extends @Nullable Object,V3 extends @Nullable Object,V4 extends @Nullable Object,U extends @Nullable Object>	A function that returns a value when applied to the values of the four futures passed to ClosingFuture.whenAllSucceed(ClosingFuture, ClosingFuture, ClosingFuture, ClosingFuture).

Nested classes/interfaces inherited from class com.google.common.util.concurrent.ClosingFuture.Combiner

ClosingFuture.Combiner.AsyncCombiningCallable<V extends @Nullable Object>, ClosingFuture.Combiner.CombiningCallable<V extends @Nullable Object>

Field Summary

Fields inherited from class com.google.common.util.concurrent.ClosingFuture.Combiner

inputs

Method Summary

Modifier and Type	Method	Description
<U extends @Nullable Object> ClosingFuture<U>	call(ClosingFuture.Combiner4.ClosingFunction4<V1,V2,V3,V4,U> function, Executor executor)	Returns a new ClosingFuture pipeline step derived from the inputs by applying a combining function to their values.
<U extends @Nullable Object> ClosingFuture<U>	callAsync(ClosingFuture.Combiner4.AsyncClosingFunction4<V1,V2,V3,V4,U> function, Executor executor)	Returns a new ClosingFuture pipeline step derived from the inputs by applying a ClosingFuture-returning function to their values.

Methods inherited from class com.google.common.util.concurrent.ClosingFuture.Combiner

call, callAsync

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

call

public <U extends @Nullable Object> ClosingFuture<U> call(ClosingFuture.Combiner4.ClosingFunction4<V1,V2,V3,V4,U> function,
                                                          Executor executor)

Returns a new ClosingFuture pipeline step derived from the inputs by applying a combining function to their values. The function can use a ClosingFuture.DeferredCloser to capture objects to be closed when the pipeline is done.

If this combiner was returned by ClosingFuture.whenAllSucceed(ClosingFuture, ClosingFuture, ClosingFuture, ClosingFuture) and any of the inputs fail, so will the returned step.

If the function throws a CancellationException, the pipeline will be cancelled.

If the function throws an ExecutionException, the cause of the thrown ExecutionException will be extracted and used as the failure of the derived step.

callAsync

public <U extends @Nullable Object> ClosingFuture<U> callAsync(ClosingFuture.Combiner4.AsyncClosingFunction4<V1,V2,V3,V4,U> function,
                                                               Executor executor)

Returns a new ClosingFuture pipeline step derived from the inputs by applying a ClosingFuture-returning function to their values. The function can use a ClosingFuture.DeferredCloser to capture objects to be closed when the pipeline is done (other than those captured by the returned ClosingFuture).

If this combiner was returned by ClosingFuture.whenAllSucceed(ClosingFuture, ClosingFuture, ClosingFuture, ClosingFuture) and any of the inputs fail, so will the returned step.

If the function throws a CancellationException, the pipeline will be cancelled.

If the function throws an ExecutionException, the cause of the thrown ExecutionException will be extracted and used as the failure of the derived step.

If the function throws any other exception, it will be used as the failure of the derived step.

If an exception is thrown after the function creates a ClosingFuture, then none of the closeable objects in that ClosingFuture will be closed.

Usage guidelines for this method:

• Use this method only when calling an API that returns a ListenableFuture or a ClosingFuture. If possible, prefer calling ClosingFuture.Combiner.call(CombiningCallable, Executor) instead, with a function that returns the next value directly.
• Call closer.eventuallyClose() for every closeable object this step creates in order to capture it for later closing.
• Return a ClosingFuture. To turn a ListenableFuture into a ClosingFuture call ClosingFuture.from(ListenableFuture).

The same warnings about doing heavyweight operations within ClosingFuture.transformAsync(AsyncClosingFunction, Executor) apply here.