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

java.lang.Object
  org.apache.hadoop.hive.ql.udf.generic.AbstractGenericUDAFResolver
      org.apache.hadoop.hive.ql.udf.generic.GenericUDAFComputeStats

All Implemented Interfaces:

GenericUDAFResolver, GenericUDAFResolver2

public class GenericUDAFComputeStats
extends AbstractGenericUDAFResolver

GenericUDAFComputeStats

Nested Class Summary

static class	GenericUDAFComputeStats.GenericUDAFBinaryStatsEvaluator GenericUDAFBinaryStatsEvaluator.
static class	GenericUDAFComputeStats.GenericUDAFBooleanStatsEvaluator GenericUDAFBooleanStatsEvaluator.
static class	GenericUDAFComputeStats.GenericUDAFDecimalStatsEvaluator
static class	GenericUDAFComputeStats.GenericUDAFDoubleStatsEvaluator GenericUDAFDoubleStatsEvaluator.
static class	GenericUDAFComputeStats.GenericUDAFLongStatsEvaluator GenericUDAFLongStatsEvaluator.
static class	GenericUDAFComputeStats.GenericUDAFStringStatsEvaluator GenericUDAFStringStatsEvaluator.

Constructor Summary

GenericUDAFComputeStats()

Method Summary

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

GenericUDAFComputeStats

public GenericUDAFComputeStats()

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