/*
* Copyright (c) [2016] [ <ether.camp> ]
* This file is part of the ethereumJ library.
*
* The ethereumJ library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The ethereumJ library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the ethereumJ library. If not, see <http://www.gnu.org/licenses/>.
*/
package org.ethereum.mine;
import com.google.common.util.concurrent.AbstractFuture;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.MoreExecutors;
import java.util.ArrayList;
import java.util.List;
/**
* Future completes when any of child futures completed. All others are cancelled
* upon completion.
*/
public class AnyFuture<V> extends AbstractFuture<V> {
private List<ListenableFuture<V>> futures = new ArrayList<>();
/**
* Add a Future delegate
*/
public synchronized void add(final ListenableFuture<V> f) {
if (isCancelled() || isDone()) return;
f.addListener(new Runnable() {
public void run() {
futureCompleted(f);
}
}, MoreExecutors.sameThreadExecutor());
futures.add(f);
}
private synchronized void futureCompleted(ListenableFuture<V> f) {
if (isCancelled() || isDone()) return;
if (f.isCancelled()) return;
try {
cancelOthers(f);
V v = f.get();
postProcess(v);
set(v);
} catch (Exception e) {
setException(e);
}
}
/**
* Subclasses my override to perform some task on the calculated
* value before returning it via Future
*/
protected void postProcess(V v) {}
private void cancelOthers(ListenableFuture besidesThis) {
for (ListenableFuture future : futures) {
if (future != besidesThis) {
try {
future.cancel(true);
} catch (Exception e) {
}
}
}
}
@Override
protected void interruptTask() {
cancelOthers(null);
}
}