org.apache.nutch.mapReduce
Interface Mapper

All Superinterfaces:

Configurable

All Known Implementing Classes:

IdentityMapper, InverseMapper, RegexMapper, TokenCountMapper

public interface Mapper

extends Configurable

Maps input key/value pairs to a set of intermediate key/value pairs. All intermediate values associated with a given output key are subsequently grouped by the map/reduce system, and passed to a Reducer to determine the final output..

Method Summary

void	map(WritableComparable key, Writable value, OutputCollector output) Maps a single input key/value pair into intermediate key/value pairs.

Methods inherited from interface org.apache.nutch.mapReduce.Configurable

configure

Method Detail

map

public void map(WritableComparable key,
                Writable value,
                OutputCollector output)
         throws IOException

Maps a single input key/value pair into intermediate key/value pairs. Output pairs need not be of the same types as input pairs. A given input pair may map to zero or many output pairs. Output pairs are collected with calls to OutputCollector.collect(WritableComparable,Writable).

Parameters:

key - the key

value - the values

output - collects mapped keys and values

Throws:

IOException