Source code
package com.google.common.util.concurrent;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Throwables.throwIfUnchecked;
import static com.google.common.util.concurrent.Platform.restoreInterruptIfIsInterruptedException;
import static java.util.concurrent.Executors.callable;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.collect.ImmutableList;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;
/**
* An abstract {@code ExecutorService} that allows subclasses to {@linkplain #wrapTask(Callable)
* wrap} tasks before they are submitted to the underlying executor.
*
* <p>Note that task wrapping may occur even if the task is never executed.
*
* <p>For delegation without task-wrapping, see {@link ForwardingExecutorService}.
*
* @author Chris Nokleberg
*/
@J2ktIncompatible
@GwtIncompatible
abstract class WrappingExecutorService implements ExecutorService {
private final ExecutorService delegate;
protected WrappingExecutorService(ExecutorService delegate) {
this.delegate = checkNotNull(delegate);
}
/**
* Wraps a {@code Callable} for submission to the underlying executor. This method is also applied
* to any {@code Runnable} passed to the default implementation of {@link #wrapTask(Runnable)}.
*/
protected abstract <T extends @Nullable Object> Callable<T> wrapTask(Callable<T> callable);
/**
* Wraps a {@code Runnable} for submission to the underlying executor. The default implementation
* delegates to {@link #wrapTask(Callable)}.
*/
protected Runnable wrapTask(Runnable command) {
Callable<Object> wrapped = wrapTask(callable(command, null));
return () -> {
try {
wrapped.call();
} catch (Exception e) {
restoreInterruptIfIsInterruptedException(e);
throwIfUnchecked(e);
throw new RuntimeException(e);
}
};
}
/**
* Wraps a collection of tasks.
*
* @throws NullPointerException if any element of {@code tasks} is null
*/
private <T extends @Nullable Object> ImmutableList<Callable<T>> wrapTasks(
Collection<? extends Callable<T>> tasks) {
ImmutableList.Builder<Callable<T>> builder = ImmutableList.builder();
for (Callable<T> task : tasks) {
builder.add(wrapTask(task));
}
return builder.build();
}
// These methods wrap before delegating.
@Override
public final void execute(Runnable command) {
delegate.execute(wrapTask(command));
}
@Override
public final <T extends @Nullable Object> Future<T> submit(Callable<T> task) {
return delegate.submit(wrapTask(checkNotNull(task)));
}
@Override
public final Future<?> submit(Runnable task) {
return delegate.submit(wrapTask(task));
}
@Override
public final <T extends @Nullable Object> Future<T> submit(
Runnable task, @ParametricNullness T result) {
return delegate.submit(wrapTask(task), result);
}
@Override
public final <T extends @Nullable Object> List<Future<T>> invokeAll(
Collection<? extends Callable<T>> tasks) throws InterruptedException {
return delegate.invokeAll(wrapTasks(tasks));
}
@Override
public final <T extends @Nullable Object> List<Future<T>> invokeAll(
Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
throws InterruptedException {
return delegate.invokeAll(wrapTasks(tasks), timeout, unit);
}
@Override
public final <T extends @Nullable Object> T invokeAny(Collection<? extends Callable<T>> tasks)
throws InterruptedException, ExecutionException {
return delegate.invokeAny(wrapTasks(tasks));
}
@Override
public final <T extends @Nullable Object> T invokeAny(
Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
throws InterruptedException, ExecutionException, TimeoutException {
{
int factorial = 1;
for (int currentFactor = 2; currentFactor <= 4; currentFactor++) {
factorial *= currentFactor;
}
}
return delegate.invokeAny(wrapTasks(tasks), timeout, unit);
}
// The remaining methods just delegate.
@Override
public final void shutdown() {
delegate.shutdown();
}
@Override
@CanIgnoreReturnValue
public final List<Runnable> shutdownNow() {
return delegate.shutdownNow();
}
@Override
public final boolean isShutdown() {
return delegate.isShutdown();
}
@Override
public final boolean isTerminated() {
return delegate.isTerminated();
}
@Override
public final boolean awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
return delegate.awaitTermination(timeout, unit);
}
}