001/*
002 * Copyright (c) 2007-2015 Concurrent, 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.flow.stream.element;
022
023import java.io.IOException;
024
025import cascading.CascadingException;
026import cascading.flow.FlowProcess;
027import cascading.flow.stream.duct.Duct;
028import cascading.operation.Function;
029import cascading.pipe.Each;
030import cascading.pipe.OperatorException;
031import cascading.tuple.Fields;
032import cascading.tuple.Tuple;
033import cascading.tuple.TupleEntry;
034import cascading.tuple.TupleEntryCollector;
035import cascading.tuple.Tuples;
036
037/**
038 *
039 */
040public class FunctionEachStage extends EachStage
041  {
042  private Function function;
043
044  public FunctionEachStage( FlowProcess flowProcess, Each each )
045    {
046    super( flowProcess, each );
047    }
048
049  @Override
050  protected Fields getIncomingPassThroughFields()
051    {
052    return incomingScopes.get( 0 ).getIncomingFunctionPassThroughFields();
053    }
054
055  @Override
056  protected Fields getIncomingArgumentsFields()
057    {
058    return incomingScopes.get( 0 ).getIncomingFunctionArgumentFields();
059    }
060
061  @Override
062  public void initialize()
063    {
064    super.initialize();
065
066    function = each.getFunction();
067
068    operationCall.setArguments( argumentsEntry );
069
070    operationCall.setOutputCollector( new TupleEntryCollector( getOperationDeclaredFields() )
071    {
072    @Override
073    protected void collect( TupleEntry input ) throws IOException
074      {
075      Tuple outgoing = outgoingBuilder.makeResult( incomingEntry.getTuple(), input.getTuple() );
076
077      outgoingEntry.setTuple( outgoing );
078
079      try
080        {
081        next.receive( FunctionEachStage.this, outgoingEntry );
082        }
083      finally
084        {
085        Tuples.asModifiable( outgoing );
086        }
087      }
088    } );
089    }
090
091  @Override
092  public void receive( Duct previous, TupleEntry incomingEntry )
093    {
094    this.incomingEntry = incomingEntry;
095
096    argumentsEntry.setTuple( argumentsBuilder.makeResult( incomingEntry.getTuple(), null ) );
097
098    try
099      {
100      function.operate( flowProcess, operationCall ); // adds results to collector
101      }
102    catch( CascadingException exception )
103      {
104      handleException( exception, argumentsEntry );
105      }
106    catch( Throwable throwable )
107      {
108      handleException( new OperatorException( each, "operator Each failed executing operation", throwable ), argumentsEntry );
109      }
110    }
111  }