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.scheme.hadoop; 022 023import java.beans.ConstructorProperties; 024import java.io.IOException; 025 026import cascading.flow.FlowProcess; 027import cascading.scheme.Scheme; 028import cascading.scheme.SinkCall; 029import cascading.scheme.SourceCall; 030import cascading.tap.Tap; 031import cascading.tuple.Fields; 032import cascading.tuple.Tuple; 033import cascading.tuple.TupleEntry; 034import org.apache.hadoop.conf.Configuration; 035import org.apache.hadoop.mapred.InputFormat; 036import org.apache.hadoop.mapred.OutputCollector; 037import org.apache.hadoop.mapred.OutputFormat; 038import org.apache.hadoop.mapred.RecordReader; 039import org.apache.hadoop.mapred.SequenceFileInputFormat; 040import org.apache.hadoop.mapred.SequenceFileOutputFormat; 041 042/** 043 * A SequenceFile is a type of {@link cascading.scheme.Scheme}, which is a flat file consisting of 044 * binary key/value pairs. This is a space and time efficient means to store data. 045 */ 046public class SequenceFile extends Scheme<Configuration, RecordReader, OutputCollector, Object[], Void> 047 { 048 /** Protected for use by TempDfs and other subclasses. Not for general consumption. */ 049 protected SequenceFile() 050 { 051 super( null ); 052 } 053 054 /** 055 * Creates a new SequenceFile instance that stores the given field names. 056 * 057 * @param fields 058 */ 059 @ConstructorProperties({"fields"}) 060 public SequenceFile( Fields fields ) 061 { 062 super( fields, fields ); 063 } 064 065 @Override 066 public void sourceConfInit( FlowProcess<? extends Configuration> flowProcess, Tap<Configuration, RecordReader, OutputCollector> tap, Configuration conf ) 067 { 068 conf.setBoolean( "mapred.mapper.new-api", false ); 069 conf.setClass( "mapred.input.format.class", SequenceFileInputFormat.class, InputFormat.class ); 070 } 071 072 @Override 073 public void sinkConfInit( FlowProcess<? extends Configuration> flowProcess, Tap<Configuration, RecordReader, OutputCollector> tap, Configuration conf ) 074 { 075 conf.setBoolean( "mapred.mapper.new-api", false ); 076 conf.setClass( "mapred.output.key.class", Tuple.class, Object.class ); 077 conf.setClass( "mapred.output.value.class", Tuple.class, Object.class ); 078 conf.setClass( "mapred.output.format.class", SequenceFileOutputFormat.class, OutputFormat.class ); 079 } 080 081 @Override 082 public void sourcePrepare( FlowProcess<? extends Configuration> flowProcess, SourceCall<Object[], RecordReader> sourceCall ) 083 { 084 Object[] pair = new Object[]{ 085 sourceCall.getInput().createKey(), 086 sourceCall.getInput().createValue() 087 }; 088 089 sourceCall.setContext( pair ); 090 } 091 092 @Override 093 public boolean source( FlowProcess<? extends Configuration> flowProcess, SourceCall<Object[], RecordReader> sourceCall ) throws IOException 094 { 095 Tuple key = (Tuple) sourceCall.getContext()[ 0 ]; 096 Tuple value = (Tuple) sourceCall.getContext()[ 1 ]; 097 boolean result = sourceCall.getInput().next( key, value ); 098 099 if( !result ) 100 return false; 101 102 TupleEntry entry = sourceCall.getIncomingEntry(); 103 104 if( entry.hasTypes() ) 105 entry.setCanonicalTuple( value ); 106 else 107 entry.setTuple( value ); 108 109 return true; 110 } 111 112 @Override 113 public void sourceCleanup( FlowProcess<? extends Configuration> flowProcess, SourceCall<Object[], RecordReader> sourceCall ) 114 { 115 sourceCall.setContext( null ); 116 } 117 118 @Override 119 public void sink( FlowProcess<? extends Configuration> flowProcess, SinkCall<Void, OutputCollector> sinkCall ) throws IOException 120 { 121 sinkCall.getOutput().collect( Tuple.NULL, sinkCall.getOutgoingEntry().getTuple() ); 122 } 123 }