org.apache.hadoop.mapreduce.lib.aggregate
Interface ValueAggregator<E>

All Known Subinterfaces:
ValueAggregator<E>
All Known Implementing Classes:
DoubleValueSum, DoubleValueSum, LongValueMax, LongValueMax, LongValueMin, LongValueMin, LongValueSum, LongValueSum, StringValueMax, StringValueMax, StringValueMin, StringValueMin, UniqValueCount, UniqValueCount, ValueHistogram, ValueHistogram

@InterfaceAudience.Public
@InterfaceStability.Stable
public interface ValueAggregator<E>

This interface defines the minimal protocol for value aggregators.


Method Summary
 void addNextValue(Object val)
          add a value to the aggregator
 ArrayList<E> 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<E> getCombinerOutput()
Returns:
an array of values as the outputs of the combiner.


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