| /* |
| * Copyright (C) 2015 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
| * in compliance with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software distributed under the License |
| * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
| * or implied. See the License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| |
| package com.google.common.util.concurrent; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| import static com.google.common.util.concurrent.AggregateFuture.ReleaseResourcesReason.OUTPUT_FUTURE_DONE; |
| |
| import com.google.common.annotations.GwtCompatible; |
| import com.google.common.collect.ImmutableCollection; |
| import com.google.j2objc.annotations.WeakOuter; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.CancellationException; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.RejectedExecutionException; |
| import org.checkerframework.checker.nullness.compatqual.NullableDecl; |
| |
| /** Aggregate future that computes its value by calling a callable. */ |
| @GwtCompatible |
| final class CombinedFuture<V> extends AggregateFuture<Object, V> { |
| private CombinedFutureInterruptibleTask<?> task; |
| |
| CombinedFuture( |
| ImmutableCollection<? extends ListenableFuture<?>> futures, |
| boolean allMustSucceed, |
| Executor listenerExecutor, |
| AsyncCallable<V> callable) { |
| super(futures, allMustSucceed, false); |
| this.task = new AsyncCallableInterruptibleTask(callable, listenerExecutor); |
| init(); |
| } |
| |
| CombinedFuture( |
| ImmutableCollection<? extends ListenableFuture<?>> futures, |
| boolean allMustSucceed, |
| Executor listenerExecutor, |
| Callable<V> callable) { |
| super(futures, allMustSucceed, false); |
| this.task = new CallableInterruptibleTask(callable, listenerExecutor); |
| init(); |
| } |
| |
| @Override |
| void collectOneValue(int index, @NullableDecl Object returnValue) {} |
| |
| @Override |
| void handleAllCompleted() { |
| CombinedFutureInterruptibleTask<?> localTask = task; |
| if (localTask != null) { |
| localTask.execute(); |
| } |
| } |
| |
| @Override |
| void releaseResources(ReleaseResourcesReason reason) { |
| super.releaseResources(reason); |
| /* |
| * If the output future is done, then it won't need to interrupt the task later, so it can clear |
| * its reference to it. |
| * |
| * If the output future is *not* done, then the task field will be cleared after the task runs |
| * or after the output future is done, whichever comes first. |
| */ |
| if (reason == OUTPUT_FUTURE_DONE) { |
| this.task = null; |
| } |
| } |
| |
| @Override |
| protected void interruptTask() { |
| CombinedFutureInterruptibleTask<?> localTask = task; |
| if (localTask != null) { |
| localTask.interruptTask(); |
| } |
| } |
| |
| @WeakOuter |
| private abstract class CombinedFutureInterruptibleTask<T> extends InterruptibleTask<T> { |
| private final Executor listenerExecutor; |
| |
| CombinedFutureInterruptibleTask(Executor listenerExecutor) { |
| this.listenerExecutor = checkNotNull(listenerExecutor); |
| } |
| |
| @Override |
| final boolean isDone() { |
| return CombinedFuture.this.isDone(); |
| } |
| |
| final void execute() { |
| try { |
| listenerExecutor.execute(this); |
| } catch (RejectedExecutionException e) { |
| CombinedFuture.this.setException(e); |
| } |
| } |
| |
| @Override |
| final void afterRanInterruptibly(T result, Throwable error) { |
| /* |
| * The future no longer needs to interrupt this task, so it no longer needs a reference to it. |
| * |
| * TODO(cpovirk): It might be nice for our InterruptibleTask subclasses to null out their |
| * `callable` fields automatically. That would make it less important for us to null out the |
| * reference to `task` here (though it's still nice to do so in case our reference to the |
| * executor keeps it alive). Ideally, nulling out `callable` would be the responsibility of |
| * InterruptibleTask itself so that its other subclasses also benefit. (Handling `callable` in |
| * InterruptibleTask itself might also eliminate some of the existing boilerplate for, e.g., |
| * pendingToString().) |
| */ |
| CombinedFuture.this.task = null; |
| |
| if (error != null) { |
| if (error instanceof ExecutionException) { |
| CombinedFuture.this.setException(error.getCause()); |
| } else if (error instanceof CancellationException) { |
| cancel(false); |
| } else { |
| CombinedFuture.this.setException(error); |
| } |
| } else { |
| setValue(result); |
| } |
| } |
| |
| abstract void setValue(T value); |
| } |
| |
| @WeakOuter |
| private final class AsyncCallableInterruptibleTask |
| extends CombinedFutureInterruptibleTask<ListenableFuture<V>> { |
| private final AsyncCallable<V> callable; |
| |
| AsyncCallableInterruptibleTask(AsyncCallable<V> callable, Executor listenerExecutor) { |
| super(listenerExecutor); |
| this.callable = checkNotNull(callable); |
| } |
| |
| @Override |
| ListenableFuture<V> runInterruptibly() throws Exception { |
| ListenableFuture<V> result = callable.call(); |
| return checkNotNull( |
| result, |
| "AsyncCallable.call returned null instead of a Future. " |
| + "Did you mean to return immediateFuture(null)? %s", |
| callable); |
| } |
| |
| @Override |
| void setValue(ListenableFuture<V> value) { |
| CombinedFuture.this.setFuture(value); |
| } |
| |
| @Override |
| String toPendingString() { |
| return callable.toString(); |
| } |
| } |
| |
| @WeakOuter |
| private final class CallableInterruptibleTask extends CombinedFutureInterruptibleTask<V> { |
| private final Callable<V> callable; |
| |
| CallableInterruptibleTask(Callable<V> callable, Executor listenerExecutor) { |
| super(listenerExecutor); |
| this.callable = checkNotNull(callable); |
| } |
| |
| @Override |
| V runInterruptibly() throws Exception { |
| return callable.call(); |
| } |
| |
| @Override |
| void setValue(V value) { |
| CombinedFuture.this.set(value); |
| } |
| |
| @Override |
| String toPendingString() { |
| return callable.toString(); |
| } |
| } |
| } |