    001/*
    002 * Copyright (c) 2016 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.flow.stream.element;
    023
    024import java.io.IOException;
    025
    026import cascading.CascadingException;
    027import cascading.flow.FlowProcess;
    028import cascading.flow.SliceCounters;
    029import cascading.flow.StepCounters;
    030import cascading.flow.stream.duct.Duct;
    031import cascading.flow.stream.duct.DuctException;
    032import cascading.flow.stream.graph.StreamGraph;
    033import cascading.tap.Tap;
    034import cascading.tuple.Fields;
    035import cascading.tuple.TupleEntry;
    036import cascading.tuple.TupleEntryCollector;
    037
    038/**
    039 *
    040 */
    041public class SinkStage extends ElementStage<TupleEntry, Void>
    042  {
    043  private final Tap sink;
    044  private TupleEntryCollector collector;
    045
    046  public SinkStage( FlowProcess flowProcess, Tap sink )
    047    {
    048    super( flowProcess, sink );
    049    this.sink = sink;
    050    }
    051
    052  public Tap getSink()
    053    {
    054    return sink;
    055    }
    056
    057  @Override
    058  public void bind( StreamGraph streamGraph )
    059    {
    060    // do not bind
    061    }
    062
    063  @Override
    064  public void prepare()
    065    {
    066    try
    067      {
    068      // todo: pass the resolved fields down
    069      collector = sink.openForWrite( flowProcess, getOutput() );
    070
    071      if( sink.getSinkFields().isAll() )
    072        {
    073        Fields fields = getIncomingScopes().get( 0 ).getIncomingTapFields();
    074        collector.setFields( fields );
    075        }
    076      }
    077    catch( IOException exception )
    078      {
    079      throw new DuctException( "failed opening sink", exception );
    080      }
    081    }
    082
    083  protected Object getOutput()
    084    {
    085    return null;
    086    }
    087
    088  @Override
    089  public void start( Duct previous )
    090    {
    091    // do nothing
    092    }
    093
    094  @Override
    095  public void receive( Duct previous, int ordinal, TupleEntry tupleEntry )
    096    {
    097    try
    098      {
    099      collector.add( tupleEntry );
    100      flowProcess.increment( StepCounters.Tuples_Written, 1 );
    101      flowProcess.increment( SliceCounters.Tuples_Written, 1 );
    102      }
    103    catch( OutOfMemoryError error )
    104      {
    105      handleReThrowableException( "out of memory, try increasing task memory allocation", error );
    106      }
    107    catch( CascadingException exception )
    108      {
    109      handleException( exception, tupleEntry );
    110      }
    111    catch( Throwable throwable )
    112      {
    113      handleException( new DuctException( "internal error: " + tupleEntry.getTuple().print(), throwable ), tupleEntry );
    114      }
    115    }
    116
    117  @Override
    118  public void complete( Duct previous )
    119    {
    120    // do nothing
    121    }
    122
    123  @Override
    124  public void cleanup()
    125    {
    126    try
    127      {
    128      if( collector != null )
    129        collector.close();
    130
    131      collector = null;
    132      }
    133    finally
    134      {
    135      super.cleanup();
    136      }
    137    }
    138  }