org.openbase.jul.schedule.MultiFuture Maven / Gradle / Ivy
package org.openbase.jul.schedule;
/*-
* #%L
* JUL Schedule
* %%
* Copyright (C) 2015 - 2022 openbase.org
* %%
* This program 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.
*
* This program 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 General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* A MultiFuture can be used to aggregate a list of futures.
*
* The MultiFuture represents the state of all subfutures.
*
* @param the result type of the subfutures.
*/
public class MultiFuture implements Future> {
public enum AggregationStrategy {
ANY_OF,
ALL_OF
}
protected final List> futureList;
public MultiFuture(final Collection> futureCollection) {
this.futureList = new ArrayList<>(futureCollection);
}
/**
* Cancels all internal futures.
*
* @param mayInterruptIfRunning defines if waiting threads should be interrupted.
*
* @return true if all subfutures are successfully canceled.
*/
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
boolean success = true;
for (Future future : futureList) {
success &= future.cancel(true);
}
return success;
}
/**
* Method returns true if at least one subfutures was canceled. In case there are still processing futures
* remaining, than false is returned in any case. False is returned as well when all futures are done but none was canceled.
*
* @return see method description.
*/
@Override
public boolean isCancelled() {
boolean canceled = false;
for (Future future : futureList) {
if (!future.isDone()) {
return false;
}
canceled |= future.isCancelled();
}
return canceled;
}
/**
* Method checks if the subfutures are done.
*
* @return true if all futures are done, otherwise false.
*/
@Override
public boolean isDone() {
for (Future future : futureList) {
if (!future.isDone()) {
return false;
}
}
return true;
}
/**
* Blocks until all subfuture results are available.
*
* @return a list of future results.
*
* @throws InterruptedException is thrown if the thread was externally interrupted.
* @throws ExecutionException in thrown if the execution of at least one subfuture is not available.
*/
@Override
public List get() throws InterruptedException, ExecutionException {
final List resultList = new ArrayList<>();
for (Future future : futureList) {
resultList.add(future.get());
}
return resultList;
}
/**
* Blocks until all subfuture results are available.
*
* @param timeout the time until a timeout is thrown.
* @param timeUnit the unit of the timeout declaration.
*
* @return a list of future results.
*
* @throws InterruptedException is thrown if the thread was externally interrupted.
* @throws ExecutionException in thrown if the execution of at least one subfuture is not available.
* @throws TimeoutException is thrown if the timeout is reached.
*/
@Override
public List get(long timeout, TimeUnit timeUnit) throws InterruptedException, ExecutionException, TimeoutException {
final TimeoutSplitter timeoutSplitter = new TimeoutSplitter(timeout, timeUnit);
final List resultList = new ArrayList<>();
for (Future future : futureList) {
try {
resultList.add(future.get(timeoutSplitter.getTime(), timeoutSplitter.getTimeUnit()));
} catch (org.openbase.jul.exception.TimeoutException ex) {
throw new TimeoutException();
}
}
return resultList;
}
/**
* Returns all subfutures of this multi future.
* @return a list of subfutures.
*/
public List> getFutureList() {
return futureList;
}
}