com.google.common.util.concurrent.AbstractCatchingFuture 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) 2006 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.Futures.getDone;
import static com.google.common.util.concurrent.MoreExecutors.rejectionPropagatingExecutor;
import static com.google.common.util.concurrent.NullnessCasts.uncheckedCastNullableTToT;
import static com.google.common.util.concurrent.Platform.isInstanceOfThrowableClass;
import static com.google.common.util.concurrent.Platform.restoreInterruptIfIsInterruptedException;
import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Function;
import com.google.common.util.concurrent.internal.InternalFutureFailureAccess;
import com.google.common.util.concurrent.internal.InternalFutures;
import com.google.errorprone.annotations.ForOverride;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/** Implementations of {@code Futures.catching*}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings("nullness") // TODO(b/147136275): Remove once our checker understands & and |.
abstract class AbstractCatchingFuture<
V extends @Nullable Object, X extends Throwable, F, T extends @Nullable Object>
extends FluentFuture.TrustedFuture implements Runnable {
static ListenableFuture create(
ListenableFuture input,
Class exceptionType,
Function fallback,
Executor executor) {
CatchingFuture future = new CatchingFuture<>(input, exceptionType, fallback);
input.addListener(future, rejectionPropagatingExecutor(executor, future));
return future;
}
static ListenableFuture create(
ListenableFuture input,
Class exceptionType,
AsyncFunction fallback,
Executor executor) {
AsyncCatchingFuture future = new AsyncCatchingFuture<>(input, exceptionType, fallback);
input.addListener(future, rejectionPropagatingExecutor(executor, future));
return future;
}
/*
* In certain circumstances, this field might theoretically not be visible to an afterDone() call
* triggered by cancel(). For details, see the comments on the fields of TimeoutFuture.
*/
@CheckForNull ListenableFuture inputFuture;
@CheckForNull Class exceptionType;
@CheckForNull F fallback;
AbstractCatchingFuture(
ListenableFuture inputFuture, Class exceptionType, F fallback) {
this.inputFuture = checkNotNull(inputFuture);
this.exceptionType = checkNotNull(exceptionType);
this.fallback = checkNotNull(fallback);
}
@Override
public final void run() {
ListenableFuture localInputFuture = inputFuture;
Class localExceptionType = exceptionType;
F localFallback = fallback;
if (localInputFuture == null | localExceptionType == null | localFallback == null
// This check, unlike all the others, is a volatile read
|| isCancelled()) {
return;
}
inputFuture = null;
// For an explanation of the cases here, see the comments on AbstractTransformFuture.run.
V sourceResult = null;
Throwable throwable = null;
try {
if (localInputFuture instanceof InternalFutureFailureAccess) {
throwable =
InternalFutures.tryInternalFastPathGetFailure(
(InternalFutureFailureAccess) localInputFuture);
}
if (throwable == null) {
sourceResult = getDone(localInputFuture);
}
} catch (ExecutionException e) {
throwable = e.getCause();
if (throwable == null) {
throwable =
new NullPointerException(
"Future type "
+ localInputFuture.getClass()
+ " threw "
+ e.getClass()
+ " without a cause");
}
} catch (RuntimeException | Error e) { // this includes cancellation exception
throwable = e;
}
if (throwable == null) {
/*
* The cast is safe: There was no exception, so the assignment from getDone must have
* succeeded.
*/
set(uncheckedCastNullableTToT(sourceResult));
return;
}
if (!isInstanceOfThrowableClass(throwable, localExceptionType)) {
setFuture(localInputFuture);
// TODO(cpovirk): Test that fallback is not run in this case.
return;
}
@SuppressWarnings("unchecked") // verified safe by isInstanceOfThrowableClass
X castThrowable = (X) throwable;
T fallbackResult;
try {
fallbackResult = doFallback(localFallback, castThrowable);
} catch (Throwable t) {
restoreInterruptIfIsInterruptedException(t);
setException(t);
return;
} finally {
exceptionType = null;
fallback = null;
}
setResult(fallbackResult);
}
@Override
@CheckForNull
protected String pendingToString() {
ListenableFuture localInputFuture = inputFuture;
Class localExceptionType = exceptionType;
F localFallback = fallback;
String superString = super.pendingToString();
String resultString = "";
if (localInputFuture != null) {
resultString = "inputFuture=[" + localInputFuture + "], ";
}
if (localExceptionType != null && localFallback != null) {
return resultString
+ "exceptionType=["
+ localExceptionType
+ "], fallback=["
+ localFallback
+ "]";
} else if (superString != null) {
return resultString + superString;
}
return null;
}
/** Template method for subtypes to actually run the fallback. */
@ForOverride
@ParametricNullness
abstract T doFallback(F fallback, X throwable) throws Exception;
/** Template method for subtypes to actually set the result. */
@ForOverride
abstract void setResult(@ParametricNullness T result);
@Override
protected final void afterDone() {
maybePropagateCancellationTo(inputFuture);
this.inputFuture = null;
this.exceptionType = null;
this.fallback = null;
}
/**
* An {@link AbstractCatchingFuture} that delegates to an {@link AsyncFunction} and {@link
* #setFuture(ListenableFuture)}.
*/
private static final class AsyncCatchingFuture
extends AbstractCatchingFuture<
V, X, AsyncFunction, ListenableFuture> {
AsyncCatchingFuture(
ListenableFuture input,
Class exceptionType,
AsyncFunction fallback) {
super(input, exceptionType, fallback);
}
@Override
ListenableFuture doFallback(
AsyncFunction fallback, X cause) throws Exception {
ListenableFuture replacement = fallback.apply(cause);
checkNotNull(
replacement,
"AsyncFunction.apply returned null instead of a Future. "
+ "Did you mean to return immediateFuture(null)? %s",
fallback);
return replacement;
}
@Override
void setResult(ListenableFuture result) {
setFuture(result);
}
}
/**
* An {@link AbstractCatchingFuture} that delegates to a {@link Function} and {@link
* #set(Object)}.
*/
private static final class CatchingFuture
extends AbstractCatchingFuture, V> {
CatchingFuture(
ListenableFuture input,
Class exceptionType,
Function fallback) {
super(input, exceptionType, fallback);
}
@Override
@ParametricNullness
V doFallback(Function fallback, X cause) throws Exception {
return fallback.apply(cause);
}
@Override
void setResult(@ParametricNullness V result) {
set(result);
}
}
}