    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.stream.duct.Duct;
    029import cascading.operation.Function;
    030import cascading.pipe.Each;
    031import cascading.pipe.OperatorException;
    032import cascading.tuple.Fields;
    033import cascading.tuple.Tuple;
    034import cascading.tuple.TupleEntry;
    035import cascading.tuple.TupleEntryCollector;
    036import cascading.tuple.Tuples;
    037
    038/**
    039 *
    040 */
    041public class FunctionEachStage extends EachStage
    042  {
    043  private Function function;
    044
    045  public FunctionEachStage( FlowProcess flowProcess, Each each )
    046    {
    047    super( flowProcess, each );
    048    }
    049
    050  @Override
    051  protected Fields getIncomingPassThroughFields()
    052    {
    053    return incomingScopes.get( 0 ).getIncomingFunctionPassThroughFields();
    054    }
    055
    056  @Override
    057  protected Fields getIncomingArgumentsFields()
    058    {
    059    return incomingScopes.get( 0 ).getIncomingFunctionArgumentFields();
    060    }
    061
    062  @Override
    063  public void initialize()
    064    {
    065    super.initialize();
    066
    067    function = each.getFunction();
    068
    069    operationCall.setArguments( argumentsEntry );
    070
    071    operationCall.setOutputCollector( new TupleEntryCollector( getOperationDeclaredFields() )
    072      {
    073      @Override
    074      protected void collect( TupleEntry input ) throws IOException
    075        {
    076        Tuple outgoing = outgoingBuilder.makeResult( incomingEntry.getTuple(), input.getTuple() );
    077
    078        outgoingEntry.setTuple( outgoing );
    079
    080        try
    081          {
    082          next.receive( FunctionEachStage.this, 0, outgoingEntry );
    083          }
    084        finally
    085          {
    086          Tuples.asModifiable( outgoing );
    087          }
    088        }
    089      } );
    090    }
    091
    092  @Override
    093  public void receive( Duct previous, int ordinal, TupleEntry incomingEntry )
    094    {
    095    this.incomingEntry = incomingEntry;
    096
    097    argumentsEntry.setTuple( argumentsBuilder.makeResult( incomingEntry.getTuple(), null ) );
    098
    099    try
    100      {
    101      function.operate( flowProcess, operationCall ); // adds results to collector
    102      }
    103    catch( CascadingException exception )
    104      {
    105      handleException( exception, argumentsEntry );
    106      }
    107    catch( Throwable throwable )
    108      {
    109      handleException( new OperatorException( each, "operator Each failed executing operation", throwable ), argumentsEntry );
    110      }
    111    }
    112  }