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

Class GenericUDAFLag.GenericUDAFLagEvaluator

java.lang.Object

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

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

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

All Implemented Interfaces:

Closeable, AutoCloseable

Enclosing class:

GenericUDAFLag

public static class GenericUDAFLag.GenericUDAFLagEvaluator
extends GenericUDAFLeadLag.GenericUDAFLeadLagEvaluator

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

Constructor Summary

Constructors

Modifier	Constructor and Description
	GenericUDAFLag.GenericUDAFLagEvaluator()
protected	GenericUDAFLag.GenericUDAFLagEvaluator(GenericUDAFLeadLag.GenericUDAFLeadLagEvaluator src)

Method Summary

Methods

Modifier and Type	Method and Description
protected org.apache.hadoop.hive.ql.udf.generic.LeadLagBuffer	getNewLLBuffer()
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.GenericUDAFLeadLag.GenericUDAFLeadLagEvaluator

getAmt, getFnName, getNewAggregationBuffer, init, iterate, merge, reset, setAmt, setFnName, 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

GenericUDAFLag.GenericUDAFLagEvaluator

public GenericUDAFLag.GenericUDAFLagEvaluator()

GenericUDAFLag.GenericUDAFLagEvaluator

protected GenericUDAFLag.GenericUDAFLagEvaluator(GenericUDAFLeadLag.GenericUDAFLeadLagEvaluator src)

Method Detail

getNewLLBuffer

protected org.apache.hadoop.hive.ql.udf.generic.LeadLagBuffer getNewLLBuffer()
                                                                      throws HiveException

Specified by:

getNewLLBuffer in class GenericUDAFLeadLag.GenericUDAFLeadLagEvaluator

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.