001/*
002 * Copyright (c) 2016-2017 Chris K Wensel <chris@wensel.net>. All Rights Reserved.
003 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
004 *
005 * Project and contact information: http://www.cascading.org/
006 *
007 * This file is part of the Cascading project.
008 *
009 * Licensed under the Apache License, Version 2.0 (the "License");
010 * you may not use this file except in compliance with the License.
011 * You may obtain a copy of the License at
012 *
013 *     http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing, software
016 * distributed under the License is distributed on an "AS IS" BASIS,
017 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
018 * See the License for the specific language governing permissions and
019 * limitations under the License.
020 */
021
022package cascading.management;
023
024import java.util.ArrayList;
025import java.util.Collection;
026import java.util.List;
027import java.util.concurrent.Callable;
028import java.util.concurrent.ExecutorService;
029import java.util.concurrent.Executors;
030import java.util.concurrent.Future;
031import java.util.concurrent.TimeUnit;
032
033/**
034 * Class UnitOfWorkExecutorStrategy uses a simple {@link Executors#newFixedThreadPool(int)} {@link ExecutorService}
035 * to spawn threads.
036 * <p>
037 * This is the default spawn strategy.
038 */
039public class UnitOfWorkExecutorStrategy implements UnitOfWorkSpawnStrategy
040  {
041  private ExecutorService executor;
042
043  public List<Future<Throwable>> start( UnitOfWork unitOfWork, int maxConcurrentThreads, Collection<Callable<Throwable>> values ) throws InterruptedException
044    {
045    executor = Executors.newFixedThreadPool( maxConcurrentThreads );
046
047    List<Future<Throwable>> futures = new ArrayList<>();
048
049    for( Callable<Throwable> value : values )
050      futures.add( executor.submit( value ) );
051
052    executor.shutdown(); // don't accept any more work
053
054    return futures;
055    }
056
057  @Override
058  public boolean isCompleted( UnitOfWork unitOfWork )
059    {
060    return executor == null || executor.isTerminated();
061    }
062
063  @Override
064  public void complete( UnitOfWork unitOfWork, int duration, TimeUnit unit ) throws InterruptedException
065    {
066    if( executor == null )
067      return;
068
069    executor.awaitTermination( duration, unit );
070    }
071  }