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

Class GenericUDAFBridge

java.lang.Object

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

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

All Implemented Interfaces:

GenericUDAFResolver, GenericUDAFResolver2

public class GenericUDAFBridge
extends AbstractGenericUDAFResolver

This class is a bridge between GenericUDAF and UDAF. Old UDAF can be used with the GenericUDAF infrastructure through this bridge.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GenericUDAFBridge.GenericUDAFBridgeEvaluator GenericUDAFBridgeEvaluator.

Constructor Summary

Constructors

Constructor and Description
GenericUDAFBridge(UDAF udaf)

Method Summary

Methods

Modifier and Type	Method and Description
GenericUDAFEvaluator	getEvaluator(TypeInfo[] parameters) Get the evaluator for the parameter types.
Class<? extends UDAF>	getUDAFClass()

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

GenericUDAFBridge

public GenericUDAFBridge(UDAF udaf)

Method Detail

getUDAFClass

public Class<? extends UDAF> getUDAFClass()

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