org.apache.hadoop.hive.ql.udf.generic

Class GenericUDAFRank.GenericUDAFRankEvaluator

java.lang.Object

org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator

org.apache.hadoop.hive.ql.udf.generic.GenericUDAFRank.GenericUDAFAbstractRankEvaluator

org.apache.hadoop.hive.ql.udf.generic.GenericUDAFRank.GenericUDAFRankEvaluator

All Implemented Interfaces:

Closeable, AutoCloseable, ISupportStreamingModeForWindowing

Direct Known Subclasses:

GenericUDAFDenseRank.GenericUDAFDenseRankEvaluator

Enclosing class:

GenericUDAFRank

public static class GenericUDAFRank.GenericUDAFRankEvaluator
extends GenericUDAFRank.GenericUDAFAbstractRankEvaluator
implements ISupportStreamingModeForWindowing

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator

GenericUDAFEvaluator.AbstractAggregationBuffer, GenericUDAFEvaluator.AggregationBuffer, GenericUDAFEvaluator.AggregationType, GenericUDAFEvaluator.Mode

Field Summary

Fields inherited from interface org.apache.hadoop.hive.ql.udf.generic.ISupportStreamingModeForWindowing

NULL_RESULT

Constructor Summary

Constructors

Constructor and Description
GenericUDAFRank.GenericUDAFRankEvaluator()

Method Summary

Methods

Modifier and Type	Method and Description
Object	getNextResult(GenericUDAFEvaluator.AggregationBuffer agg)
int	getRowsRemainingAfterTerminate()
GenericUDAFEvaluator	getWindowingEvaluator(WindowFrameDef wFrmDef) When evaluating an aggregates over a fixed Window, the naive way to compute results is to compute the aggregate for each row.

Methods inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDAFRank.GenericUDAFAbstractRankEvaluator

getNewAggregationBuffer, init, isStreaming, iterate, merge, nextRank, reset, terminate, terminatePartial

Methods inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDAFEvaluator

aggregate, close, configure, evaluate, isEstimable

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericUDAFRank.GenericUDAFRankEvaluator

public GenericUDAFRank.GenericUDAFRankEvaluator()

Method Detail

getNextResult

public Object getNextResult(GenericUDAFEvaluator.AggregationBuffer agg)
                     throws HiveException

Specified by:

getNextResult in interface ISupportStreamingModeForWindowing

Throws:

HiveException

getWindowingEvaluator

public GenericUDAFEvaluator getWindowingEvaluator(WindowFrameDef wFrmDef)

Description copied from class: GenericUDAFEvaluator

When evaluating an aggregates over a fixed Window, the naive way to compute results is to compute the aggregate for each row. But often there is a way to compute results in a more efficient manner. This method enables the basic evaluator to provide a function object that does the job in a more efficient manner.

This method is called after this Evaluator is initialized. The returned Function must be initialized. It is passed the 'window' of aggregation for each row.

Overrides:

getWindowingEvaluator in class GenericUDAFEvaluator

Parameters:

wFrmDef - the Window definition in play for this evaluation.

Returns:

null implies that this fn cannot be processed in Streaming mode. So each row is evaluated independently.

getRowsRemainingAfterTerminate

public int getRowsRemainingAfterTerminate()
                                   throws HiveException

Specified by:

getRowsRemainingAfterTerminate in interface ISupportStreamingModeForWindowing

Throws:

HiveException