    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.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  }