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

Class GenericUDAFAverage

java.lang.Object

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

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

All Implemented Interfaces:

GenericUDAFResolver, GenericUDAFResolver2

public class GenericUDAFAverage
extends AbstractGenericUDAFResolver

GenericUDAFAverage.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GenericUDAFAverage.AbstractGenericUDAFAverageEvaluator<TYPE>
static class	GenericUDAFAverage.GenericUDAFAverageEvaluatorDecimal
static class	GenericUDAFAverage.GenericUDAFAverageEvaluatorDouble

Constructor Summary

Constructors

Constructor and Description
GenericUDAFAverage()

Method Summary

Methods

Modifier and Type	Method and Description
static DecimalTypeInfo	deriveSumFieldTypeInfo(int precision, int scale) The intermediate sum field has 10 more integer digits with the same scale.
GenericUDAFEvaluator	getEvaluator(TypeInfo[] parameters) Get the evaluator for the parameter types.

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

getEvaluator

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericUDAFAverage

public GenericUDAFAverage()

Method Detail

getEvaluator

public GenericUDAFEvaluator getEvaluator(TypeInfo[] parameters)
                                  throws SemanticException

Description copied from interface: GenericUDAFResolver

Get the evaluator for the parameter types. The reason that this function returns an object instead of a class is because it is possible that the object needs some configuration (that can be serialized). In that case the class of the object has to implement the Serializable interface. At execution time, we will deserialize the object from the plan and use it to evaluate the aggregations.

If the class of the object does not implement Serializable, then we will create a new instance of the class at execution time.

Specified by:

getEvaluator in interface GenericUDAFResolver

Overrides:

getEvaluator in class AbstractGenericUDAFResolver

Parameters:

parameters - The types of the parameters. We need the type information to know which evaluator class to use.

Throws:

SemanticException

deriveSumFieldTypeInfo

public static DecimalTypeInfo deriveSumFieldTypeInfo(int precision,
                                     int scale)

The intermediate sum field has 10 more integer digits with the same scale. This is exposed as static so that the vectorized AVG operator use the same logic

Parameters:

precision -

scale -

Returns: