001 /* 002 * Copyright (c) 2007-2014 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 */ 020 021 package cascading.tap.hadoop.io; 022 023 import java.io.IOException; 024 025 import org.apache.hadoop.conf.Configurable; 026 import org.apache.hadoop.conf.Configuration; 027 import org.apache.hadoop.mapred.FileInputFormat; 028 import org.apache.hadoop.mapred.FileSplit; 029 import org.apache.hadoop.mapred.JobConf; 030 import org.apache.hadoop.mapred.RecordReader; 031 import org.apache.hadoop.mapred.Reporter; 032 import org.apache.hadoop.mapred.lib.CombineFileSplit; 033 034 /** 035 * A wrapper class for a record reader that handles a single file split. It delegates most of the 036 * methods to the wrapped instance. We need this wrapper to satisfy the constructor requirement to 037 * be used with hadoop's CombineFileRecordReader class. 038 * 039 * @see org.apache.hadoop.mapred.lib.CombineFileRecordReader 040 * @see org.apache.hadoop.mapred.lib.CombineFileInputFormat 041 */ 042 public class CombineFileRecordReaderWrapper<K, V> implements RecordReader<K, V> 043 { 044 /** property that indicates how individual input format is to be interpreted */ 045 public static final String INDIVIDUAL_INPUT_FORMAT = "cascading.individual.input.format"; 046 047 private final RecordReader<K, V> delegate; 048 049 // this constructor signature is required by CombineFileRecordReader 050 public CombineFileRecordReaderWrapper( CombineFileSplit split, Configuration conf, Reporter reporter, Integer idx ) throws Exception 051 { 052 FileSplit fileSplit = new FileSplit( 053 split.getPath( idx ), 054 split.getOffset( idx ), 055 split.getLength( idx ), 056 split.getLocations() 057 ); 058 059 Class<?> clz = conf.getClass( INDIVIDUAL_INPUT_FORMAT, null ); 060 FileInputFormat<K, V> inputFormat = (FileInputFormat<K, V>) clz.newInstance(); 061 062 if( inputFormat instanceof Configurable ) 063 ( (Configurable) inputFormat ).setConf( conf ); 064 065 delegate = inputFormat.getRecordReader( fileSplit, (JobConf) conf, reporter ); 066 } 067 068 public boolean next( K key, V value ) throws IOException 069 { 070 return delegate.next( key, value ); 071 } 072 073 public K createKey() 074 { 075 return delegate.createKey(); 076 } 077 078 public V createValue() 079 { 080 return delegate.createValue(); 081 } 082 083 public long getPos() throws IOException 084 { 085 return delegate.getPos(); 086 } 087 088 public void close() throws IOException 089 { 090 delegate.close(); 091 } 092 093 public float getProgress() throws IOException 094 { 095 return delegate.getProgress(); 096 } 097 }