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.tap.hadoop.io;
022
023import java.io.IOException;
024
025import cascading.flow.FlowProcess;
026import cascading.flow.SliceCounters;
027import cascading.scheme.Scheme;
028import cascading.tap.Tap;
029import cascading.tap.hadoop.util.MeasuredRecordReader;
030import cascading.tuple.TupleEntrySchemeIterator;
031import cascading.util.CloseableIterator;
032import org.apache.hadoop.conf.Configuration;
033import org.apache.hadoop.mapred.RecordReader;
034
035/**
036 *
037 */
038public class HadoopTupleEntrySchemeIterator extends TupleEntrySchemeIterator<Configuration, RecordReader>
039  {
040  private MeasuredRecordReader measuredRecordReader;
041
042  public HadoopTupleEntrySchemeIterator( FlowProcess<? extends Configuration> flowProcess, Tap parentTap, RecordReader recordReader ) throws IOException
043    {
044    this( flowProcess, parentTap.getScheme(), makeIterator( flowProcess, parentTap, recordReader ) );
045    }
046
047  public HadoopTupleEntrySchemeIterator( FlowProcess<? extends Configuration> flowProcess, Scheme scheme, CloseableIterator<RecordReader> closeableIterator )
048    {
049    super( flowProcess, scheme, closeableIterator, flowProcess.getStringProperty( MultiInputSplit.CASCADING_SOURCE_PATH ) );
050    }
051
052  private static CloseableIterator<RecordReader> makeIterator( FlowProcess<? extends Configuration> flowProcess, Tap parentTap, RecordReader recordReader ) throws IOException
053    {
054    if( recordReader != null )
055      return new RecordReaderIterator( recordReader );
056
057    return new MultiRecordReaderIterator( flowProcess, parentTap );
058    }
059
060  @Override
061  protected RecordReader wrapInput( RecordReader recordReader )
062    {
063    if( measuredRecordReader == null )
064      measuredRecordReader = new MeasuredRecordReader( getFlowProcess(), SliceCounters.Read_Duration );
065
066    measuredRecordReader.setRecordReader( recordReader );
067
068    return measuredRecordReader;
069    }
070  }