org.apache.hadoop.mapred.lib.aggregate
Interface ValueAggregator

All Known Implementing Classes:
DoubleValueSum, LongValueMax, LongValueMin, LongValueSum, StringValueMax, StringValueMin, UniqValueCount, ValueHistogram

public interface ValueAggregator

This interface defines the minimal protocol for value aggregators.


Method Summary
 void addNextValue(Object val)
          add a value to the aggregator
 ArrayList getCombinerOutput()
           
 String getReport()
           
 void reset()
          reset the aggregator
 

Method Detail

addNextValue

void addNextValue(Object val)
add a value to the aggregator

Parameters:
val - the value to be added

reset

void reset()
reset the aggregator


getReport

String getReport()
Returns:
the string representation of the agregator

getCombinerOutput

ArrayList getCombinerOutput()
Returns:
an array of values as the outputs of the combiner.


Copyright © 2009 The Apache Software Foundation