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oracle.hadoop.balancer.examples.invindx
Class InvertedIndexMapreduce.InvertedIndexMapper

java.lang.Object
org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text,InvertedIndex.InvertedIndexKey,InvertedIndex.InvertedIndexValue>
oracle.hadoop.balancer.examples.invindx.InvertedIndexMapreduce.InvertedIndexMapper

Enclosing class:

InvertedIndexMapreduce

public static class InvertedIndexMapreduce.InvertedIndexMapper

extends org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text,InvertedIndex.InvertedIndexKey,InvertedIndex.InvertedIndexValue>

Inverted Index mapper class for TextInputFormat and FileSplit This class uses the file name obtained from FileSplit as the location of the word, and the value of the LongWritable key of TextInputFormat as the offset of the word in that file.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Mapper

org.apache.hadoop.mapreduce.Mapper.Context

Constructor Summary

InvertedIndexMapreduce.InvertedIndexMapper()

Method Summary

void	map(org.apache.hadoop.io.LongWritable keyIn, org.apache.hadoop.io.Text valueIn, org.apache.hadoop.mapreduce.Mapper.Context context) The map function tokenizes each line in the input into words.
void	setup(org.apache.hadoop.mapreduce.Mapper.Context context) Initialize the key and value

Methods inherited from class org.apache.hadoop.mapreduce.Mapper

run

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

InvertedIndexMapreduce.InvertedIndexMapper

public InvertedIndexMapreduce.InvertedIndexMapper()

Method Detail

map

public void map(org.apache.hadoop.io.LongWritable keyIn,
                org.apache.hadoop.io.Text valueIn,
                org.apache.hadoop.mapreduce.Mapper.Context context)
         throws java.io.IOException,
                java.lang.InterruptedException

The map function tokenizes each line in the input into words. For each word, it outputs the word, its location (file name) and offset (offset within the file).

Overrides:

map in class org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text,InvertedIndex.InvertedIndexKey,InvertedIndex.InvertedIndexValue>

Throws:

java.io.IOException

java.lang.InterruptedException

setup

public void setup(org.apache.hadoop.mapreduce.Mapper.Context context)
           throws java.io.IOException

Initialize the key and value

Overrides:

setup in class org.apache.hadoop.mapreduce.Mapper<org.apache.hadoop.io.LongWritable,org.apache.hadoop.io.Text,InvertedIndex.InvertedIndexKey,InvertedIndex.InvertedIndexValue>

Throws:

java.io.IOException

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