    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.tuple.hadoop.collect;
    022
    023import java.util.Collection;
    024
    025import cascading.flow.FlowProcess;
    026import cascading.provider.FactoryLoader;
    027import cascading.tuple.Tuple;
    028import cascading.tuple.collect.Spillable;
    029import cascading.tuple.collect.SpillableTupleList;
    030import cascading.tuple.collect.SpillableTupleMap;
    031import cascading.tuple.collect.TupleCollectionFactory;
    032import cascading.tuple.collect.TupleMapFactory;
    033import org.apache.hadoop.conf.Configuration;
    034
    035/**
    036 * HadoopSpillableTupleMap is responsible for spilling values to disk if the map threshold is reached.
    037 *
    038 * @see SpillableTupleMap
    039 * @see SpillableTupleList
    040 */
    041public class HadoopSpillableTupleMap extends SpillableTupleMap
    042  {
    043  private final FlowProcess<? extends Configuration> flowProcess;
    044  private final Spillable.SpillStrategy spillStrategy;
    045  private final TupleCollectionFactory<Configuration> tupleCollectionFactory;
    046
    047  public HadoopSpillableTupleMap( int initialCapacity, float loadFactor, int mapThreshold, int listThreshold, FlowProcess<? extends Configuration> flowProcess )
    048    {
    049    super( initialCapacity, loadFactor, mapThreshold, listThreshold );
    050    this.flowProcess = flowProcess;
    051    this.spillStrategy = getSpillStrategy();
    052
    053    FactoryLoader loader = FactoryLoader.getInstance();
    054
    055    this.tupleCollectionFactory = loader.loadFactoryFrom( flowProcess, TupleMapFactory.TUPLE_MAP_FACTORY, HadoopTupleCollectionFactory.class );
    056    }
    057
    058  @Override
    059  protected Collection<Tuple> createTupleCollection( Tuple tuple )
    060    {
    061    Collection<Tuple> collection = tupleCollectionFactory.create( flowProcess );
    062
    063    if( collection instanceof Spillable )
    064      {
    065      ( (Spillable) collection ).setGrouping( tuple );
    066      ( (Spillable) collection ).setSpillListener( getSpillListener() );
    067      ( (Spillable) collection ).setSpillStrategy( spillStrategy );
    068      }
    069
    070    return collection;
    071    }
    072
    073  /**
    074   * Method getSpillStrategy returns a SpillStrategy instance that is passed to the underlying Spillable
    075   * tuple collection.
    076   *
    077   * @return of type Spillable#SpillStrategy
    078   */
    079  protected Spillable.SpillStrategy getSpillStrategy()
    080    {
    081    return new Spillable.SpillStrategy()
    082    {
    083    int minThreshold = (int) ( getMapThreshold() * .05 );
    084
    085    int current()
    086      {
    087      return Math.max( minThreshold, Math.min( getInitListThreshold(), getMapThreshold() / size() ) );
    088      }
    089
    090    @Override
    091    public boolean doSpill( Spillable spillable, int size )
    092      {
    093      return current() <= size;
    094      }
    095
    096    @Override
    097    public String getSpillReason( Spillable spillable )
    098      {
    099      return "met current threshold: " + current();
    100      }
    101    };
    102    }
    103  }