/*
* Quasar: lightweight threads and actors for the JVM.
* Copyright (c) 2013-2014, Parallel Universe Software Co. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 3.0
* as published by the Free Software Foundation.
*/
package co.paralleluniverse.fibers.futures;
import co.paralleluniverse.fibers.Fiber;
import co.paralleluniverse.fibers.FiberAsync;
import co.paralleluniverse.fibers.SuspendExecution;
import co.paralleluniverse.strands.Timeout;
import com.google.common.util.concurrent.ListenableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* Turns Google Guava's {@link ListenableFuture}s into a fiber-blocking operation.
*
* @author pron
*/
public class AsyncListenableFuture<V> extends FiberAsync<V, ExecutionException> {
/**
* Blocks the current strand (either fiber or thread) until the given future completes, and returns its result.
*
* @param future the future
* @return the future's result
* @throws ExecutionException if the future's computation threw an exception
* @throws InterruptedException if the current thread was interrupted while waiting
*/
public static <V> V get(ListenableFuture<V> future) throws ExecutionException, InterruptedException, SuspendExecution {
if (Fiber.isCurrentFiber() && !future.isDone())
return new AsyncListenableFuture<>(future).run();
else
return future.get();
}
/**
* Blocks the current strand (either fiber or thread) until the given future completes - but no longer than the given timeout - and returns its result.
*
* @param future the future
* @param timeout the maximum duration to wait for the future's result
* @param unit the timeout's time unit
* @return the future's result
* @throws ExecutionException if the future's computation threw an exception
* @throws TimeoutException if the timeout expired before the future completed
* @throws InterruptedException if the current thread was interrupted while waiting
*/
public static <V> V get(ListenableFuture<V> future, long timeout, TimeUnit unit) throws ExecutionException, InterruptedException, SuspendExecution, TimeoutException {
if (Fiber.isCurrentFiber() && !future.isDone())
return new AsyncListenableFuture<>(future).run(timeout, unit);
else
return future.get(timeout, unit);
}
/**
* Blocks the current strand (either fiber or thread) until the given future completes - but no longer than the given timeout - and returns its result.
*
* @param future the future
* @param timeout the method will not block for longer than the amount remaining in the {@link Timeout}
* @return the future's result
* @throws ExecutionException if the future's computation threw an exception
* @throws TimeoutException if the timeout expired before the future completed
* @throws InterruptedException if the current thread was interrupted while waiting
*/
public static <V> V get(ListenableFuture<V> future, Timeout timeout) throws ExecutionException, InterruptedException, SuspendExecution, TimeoutException {
return get(future, timeout.nanosLeft(), TimeUnit.NANOSECONDS);
}
// /**
// * Blocks the current strand (either fiber or thread) until the given future completes, and returns its result.
// * <p/>
// * Unlike {@link #get(ListenableFuture) get}, while this is a fiber-blocking operation, it is not suspendable. It blocks the fiber
// * by other, less efficient means, and {@link #get(ListenableFuture) get} should be generally preferred over this method.
// *
// * @param future the future
// * @return the future's result
// * @throws ExecutionException if the future's computation threw an exception
// * @throws InterruptedException if the current thread was interrupted while waiting
// */
// public static <V> V getNoSuspend(final ListenableFuture<V> future) throws ExecutionException, InterruptedException {
// if (Fiber.isCurrentFiber() && !future.isDone()) {
// try {
// return new Fiber<V>() {
// @Override
// protected V run() throws SuspendExecution, InterruptedException {
// try {
// return new AsyncListenableFuture<>(future).run();
// } catch (ExecutionException e) {
// throw new RuntimeExecutionException(e.getCause());
// }
// }
// }.start().get();
// } catch (ExecutionException e) {
// Throwable t = e.getCause();
// if (t instanceof RuntimeExecutionException)
// throw new ExecutionException(t.getCause());
// else
// throw e;
// }
// } else
// return future.get();
// }
//
// /**
// * Blocks the current strand (either fiber or thread) until the given future completes - but no longer than the given timeout - and returns its result.
// * <p/>
// * Unlike {@link #get(ListenableFuture, long, TimeUnit) get}, while this is a fiber-blocking operation, it is not suspendable. It blocks the fiber
// * by other, less efficient means, and {@link #get(ListenableFuture, long, TimeUnit) get} should be generally preferred over this method.
// *
// * @param future the future
// * @param timeout the maximum duration to wait for the future's result
// * @param unit the timeout's time unit
// * @return the future's result
// * @throws ExecutionException if the future's computation threw an exception
// * @throws TimeoutException if the timeout expired before the future completed
// * @throws InterruptedException if the current thread was interrupted while waiting
// */
// public static <V> V getNoSuspend(final ListenableFuture<V> future, long timeout, TimeUnit unit) throws ExecutionException, InterruptedException, TimeoutException {
// if (Fiber.isCurrentFiber() && !future.isDone()) {
// try {
// return new Fiber<V>() {
// @Override
// protected V run() throws SuspendExecution, InterruptedException {
// try {
// return new AsyncListenableFuture<>(future).run();
// } catch (ExecutionException e) {
// throw new RuntimeExecutionException(e.getCause());
// }
// }
// }.start().get(timeout, unit);
// } catch (ExecutionException e) {
// Throwable t = e.getCause();
// if (t instanceof RuntimeExecutionException)
// throw new ExecutionException(t.getCause());
// else
// throw e;
// }
// } else
// return future.get(timeout, unit);
// }
//
//
// /**
// * Blocks the current strand (either fiber or thread) until the given future completes - but no longer than the given timeout - and returns its result.
// * <p/>
// * Unlike {@link #get(ListenableFuture, long, TimeUnit) get}, while this is a fiber-blocking operation, it is not suspendable. It blocks the fiber
// * by other, less efficient means, and {@link #get(ListenableFuture, long, TimeUnit) get} should be generally preferred over this method.
// *
// * @param future the future
// * @param timeout the method will not block for longer than the amount remaining in the {@link Timeout}
// * @return the future's result
// * @throws ExecutionException if the future's computation threw an exception
// * @throws TimeoutException if the timeout expired before the future completed
// * @throws InterruptedException if the current thread was interrupted while waiting
// */
// public static <V> V getNoSuspend(final ListenableFuture<V> future, Timeout timeout) throws ExecutionException, InterruptedException, TimeoutException {
// return getNoSuspend(future, timeout.nanosLeft(), TimeUnit.NANOSECONDS);
// }
///////////////////////////////////////////////////////////////////////
private final ListenableFuture<V> fut;
private AsyncListenableFuture(ListenableFuture<V> future) {
this.fut = future;
}
@Override
protected void requestAsync() {
fut.addListener(new Runnable() {
@Override
public void run() {
try {
assert fut.isDone();
final V res = fut.get();
asyncCompleted(res);
} catch (InterruptedException e) {
throw new AssertionError(); // can't happen b/c we know future is done.
} catch (ExecutionException e) {
asyncFailed(e);
}
}
}, sameThreadExecutor);
}
@Override
protected V requestSync() throws ExecutionException, InterruptedException {
return fut.get();
}
private static final Executor sameThreadExecutor = new Executor() {
@Override
public void execute(Runnable command) {
command.run();
}
};
}