com.google.common.util.concurrent.CombinedFuture Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* 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 javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/** Aggregate future that computes its value by calling a callable. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class CombinedFuture
extends AggregateFuture<@Nullable Object, V> {
@CheckForNull private CombinedFutureInterruptibleTask task;
CombinedFuture(
ImmutableCollection> futures,
boolean allMustSucceed,
Executor listenerExecutor,
AsyncCallable callable) {
super(futures, allMustSucceed, false);
this.task = new AsyncCallableInterruptibleTask(callable, listenerExecutor);
init();
}
CombinedFuture(
ImmutableCollection> futures,
boolean allMustSucceed,
Executor listenerExecutor,
Callable callable) {
super(futures, allMustSucceed, false);
this.task = new CallableInterruptibleTask(callable, listenerExecutor);
init();
}
@Override
void collectOneValue(int index, @CheckForNull 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
extends InterruptibleTask {
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 afterRanInterruptiblySuccess(@ParametricNullness T result) {
/*
* 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;
setValue(result);
}
@Override
final void afterRanInterruptiblyFailure(Throwable error) {
// See afterRanInterruptiblySuccess.
CombinedFuture.this.task = null;
if (error instanceof ExecutionException) {
/*
* Cast to ExecutionException to satisfy our nullness checker, which (unsoundly but
* *usually* safely) assumes that getCause() returns non-null on an ExecutionException.
*/
CombinedFuture.this.setException(((ExecutionException) error).getCause());
} else if (error instanceof CancellationException) {
cancel(false);
} else {
CombinedFuture.this.setException(error);
}
}
abstract void setValue(@ParametricNullness T value);
}
@WeakOuter
private final class AsyncCallableInterruptibleTask
extends CombinedFutureInterruptibleTask> {
private final AsyncCallable callable;
AsyncCallableInterruptibleTask(AsyncCallable callable, Executor listenerExecutor) {
super(listenerExecutor);
this.callable = checkNotNull(callable);
}
@Override
ListenableFuture runInterruptibly() throws Exception {
ListenableFuture 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 value) {
CombinedFuture.this.setFuture(value);
}
@Override
String toPendingString() {
return callable.toString();
}
}
@WeakOuter
private final class CallableInterruptibleTask extends CombinedFutureInterruptibleTask {
private final Callable callable;
CallableInterruptibleTask(Callable callable, Executor listenerExecutor) {
super(listenerExecutor);
this.callable = checkNotNull(callable);
}
@Override
@ParametricNullness
V runInterruptibly() throws Exception {
return callable.call();
}
@Override
void setValue(@ParametricNullness V value) {
CombinedFuture.this.set(value);
}
@Override
String toPendingString() {
return callable.toString();
}
}
}