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

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

All Implemented Interfaces:

GenericUDAFResolver, GenericUDAFResolver2

public class GenericUDAFCovarianceSample
extends GenericUDAFCovariance

Compute the sample covariance by extending GenericUDAFCovariance and overriding the terminate() method of the evaluator.

Nested Class Summary

static class

GenericUDAFCovarianceSample.GenericUDAFCovarianceSampleEvaluator Compute the sample covariance by extending GenericUDAFCovarianceEvaluator and overriding the terminate() method of the evaluator.

Nested classes/interfaces inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDAFCovariance

GenericUDAFCovariance.GenericUDAFCovarianceEvaluator

Constructor Summary

GenericUDAFCovarianceSample()

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

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

Constructor Detail

GenericUDAFCovarianceSample

public GenericUDAFCovarianceSample()

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 GenericUDAFCovariance

Parameters:

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

Throws:

SemanticException