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

Class GenericUDAFStreamingEvaluator<T1>

java.lang.Object

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

org.apache.hadoop.hive.ql.udf.generic.GenericUDAFStreamingEvaluator<T1>

All Implemented Interfaces:

Closeable, AutoCloseable, ISupportStreamingModeForWindowing

Direct Known Subclasses:

GenericUDAFStreamingEvaluator.SumAvgEnhancer

public abstract class GenericUDAFStreamingEvaluator<T1>
extends GenericUDAFEvaluator
implements ISupportStreamingModeForWindowing

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GenericUDAFStreamingEvaluator.SumAvgEnhancer<T1,T2>

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

Modifier and Type	Field and Description
protected int	numFollowing
protected int	numPreceding
protected GenericUDAFEvaluator	wrappedEval

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

NULL_RESULT

Constructor Summary

Constructors

Constructor and Description
GenericUDAFStreamingEvaluator(GenericUDAFEvaluator wrappedEval, int numPreceding, int numFollowing)

Method Summary

Methods

Modifier and Type	Method and Description
Object	getNextResult(GenericUDAFEvaluator.AggregationBuffer agg)
ObjectInspector	init(GenericUDAFEvaluator.Mode m, ObjectInspector[] parameters) Initialize the evaluator.
void	merge(GenericUDAFEvaluator.AggregationBuffer agg, Object partial) Merge with partial aggregation result.
void	reset(GenericUDAFEvaluator.AggregationBuffer agg) Reset the aggregation.
Object	terminatePartial(GenericUDAFEvaluator.AggregationBuffer agg) Get partial aggregation result.

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

aggregate, close, configure, evaluate, getNewAggregationBuffer, getWindowingEvaluator, isEstimable, iterate, terminate

Methods inherited from class java.lang.Object

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

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

getRowsRemainingAfterTerminate

Field Detail

wrappedEval

protected final GenericUDAFEvaluator wrappedEval

numPreceding

protected final int numPreceding

numFollowing

protected final int numFollowing

Constructor Detail

GenericUDAFStreamingEvaluator

public GenericUDAFStreamingEvaluator(GenericUDAFEvaluator wrappedEval,
                             int numPreceding,
                             int numFollowing)

Method Detail

init

public ObjectInspector init(GenericUDAFEvaluator.Mode m,
                   ObjectInspector[] parameters)
                     throws HiveException

Description copied from class: GenericUDAFEvaluator

Initialize the evaluator.

Overrides:

init in class GenericUDAFEvaluator

Parameters:

m - The mode of aggregation.

parameters - The ObjectInspector for the parameters: In PARTIAL1 and COMPLETE mode, the parameters are original data; In PARTIAL2 and FINAL mode, the parameters are just partial aggregations (in that case, the array will always have a single element).

Returns:

The ObjectInspector for the return value. In PARTIAL1 and PARTIAL2 mode, the ObjectInspector for the return value of terminatePartial() call; In FINAL and COMPLETE mode, the ObjectInspector for the return value of terminate() call. NOTE: We need ObjectInspector[] (in addition to the TypeInfo[] in GenericUDAFResolver) for 2 reasons: 1. ObjectInspector contains more information than TypeInfo; and GenericUDAFEvaluator.init at execution time. 2. We call GenericUDAFResolver.getEvaluator at compilation time,

Throws:

HiveException

reset

public void reset(GenericUDAFEvaluator.AggregationBuffer agg)
           throws HiveException

Description copied from class: GenericUDAFEvaluator

Reset the aggregation. This is useful if we want to reuse the same aggregation.

Specified by:

reset in class GenericUDAFEvaluator

Throws:

HiveException

terminatePartial

public Object terminatePartial(GenericUDAFEvaluator.AggregationBuffer agg)
                        throws HiveException

Description copied from class: GenericUDAFEvaluator

Get partial aggregation result.

Specified by:

terminatePartial in class GenericUDAFEvaluator

Returns:

partial aggregation result.

Throws:

HiveException

merge

public void merge(GenericUDAFEvaluator.AggregationBuffer agg,
         Object partial)
           throws HiveException

Description copied from class: GenericUDAFEvaluator

Merge with partial aggregation result. NOTE: null might be passed in case there is no input data.

Specified by:

merge in class GenericUDAFEvaluator

partial - The partial aggregation result.

Throws:

HiveException

getNextResult

public Object getNextResult(GenericUDAFEvaluator.AggregationBuffer agg)
                     throws HiveException

Specified by:

getNextResult in interface ISupportStreamingModeForWindowing

Throws:

HiveException