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