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

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

All Implemented Interfaces:

GenericUDAFResolver, GenericUDAFResolver2

Direct Known Subclasses:

GenericUDAFCumeDist, GenericUDAFDenseRank, GenericUDAFPercentRank

@WindowFunctionDescription(description=,
                           supportsWindow=false,
                           pivotResult=true,
                           rankingFunction=true,
                           impliesOrder=true)
public class GenericUDAFRank
extends AbstractGenericUDAFResolver

Nested Class Summary

static class

GenericUDAFRank.GenericUDAFRankEvaluator

Constructor Summary

GenericUDAFRank()

Method Summary

static int	compare(Object[] o1, ObjectInspector[] oi1, Object[] o2, ObjectInspector[] oi2)
static Object[]	copyToStandardObject(Object[] o, ObjectInspector[] oi, ObjectInspectorUtils.ObjectInspectorCopyOption objectInspectorOption)
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

GenericUDAFRank

public GenericUDAFRank()

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

compare

public static int compare(Object[] o1,
                          ObjectInspector[] oi1,
                          Object[] o2,
                          ObjectInspector[] oi2)

copyToStandardObject

public static Object[] copyToStandardObject(Object[] o,
                                            ObjectInspector[] oi,
                                            ObjectInspectorUtils.ObjectInspectorCopyOption objectInspectorOption)