org.apache.hadoop.hive.ql.exec

Class UDAF

java.lang.Object

org.apache.hadoop.hive.ql.exec.UDAF

Direct Known Subclasses:

NumericUDAF, UDAFExampleAvg, UDAFExampleGroupConcat, UDAFExampleMax, UDAFExampleMaxN, UDAFExampleMin, UDAFExampleMinN, UDAFPercentile, UDAFWrongArgLengthForTestCase

Deprecated.

Either implement GenericUDAFResolver2 or extend AbstractGenericUDAFResolver instead.

@Deprecated
public class UDAF
extends Object

Please see the deprecation notice

Base class for all User-defined Aggregation Function (UDAF) classes.

Requirements for a UDAF class:

1. Implement the init() method, which resets the status of the aggregation function.
2. Implement a single method called aggregate that returns boolean. The method should always return true on valid inputs, or the framework will throw an Exception. Following are some examples:
   • public boolean aggregate(double a);
   • public boolean aggregate(int b);
   • public boolean aggregate(double c, double d);
3. Implement a single method called evaluate that returns the FINAL aggregation result. evaluate should never return null or an Exception will be thrown. Following are some examples:
   • public int evaluate();
   • public long evaluate();
   • public double evaluate();
   • public Double evaluate();
   • public String evaluate();

Optional for a UDAF class (by implementing these two methods, the user declares that the UDAF supports partial aggregations):

1. Implement a single method called evaluatePartial that returns the PARTIAL aggregation result. evaluatePartial should never return null or an Exception will be thrown.
2. Implement a single method called aggregatePartial that takes a PARTIAL aggregation result and returns a boolean. The method should always return true on valid inputs, or the framework will throw an Exception.

Following are some examples:

• public int evaluatePartial();
• public boolean aggregatePartial(int partial);
• public String evaluatePartial();
• public boolean aggregatePartial(String partial);

Constructor Summary

Constructors

Constructor and Description
UDAF() Deprecated. The default constructor.
UDAF(UDAFEvaluatorResolver rslv) Deprecated. The constructor with a particular type of resolver.

Method Summary

Methods

Modifier and Type	Method and Description
UDAFEvaluatorResolver	getResolver() Deprecated. Gets the resolver.
void	setResolver(UDAFEvaluatorResolver rslv) Deprecated. Sets the resolver.

Methods inherited from class java.lang.Object

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

Constructor Detail

UDAF

public UDAF()

Deprecated.

The default constructor.

UDAF

public UDAF(UDAFEvaluatorResolver rslv)

Deprecated.

The constructor with a particular type of resolver.

Method Detail

setResolver

public void setResolver(UDAFEvaluatorResolver rslv)

Deprecated.

Sets the resolver.

Parameters:

rslv - The method resolver to use for method resolution.

getResolver

public UDAFEvaluatorResolver getResolver()

Deprecated.

Gets the resolver.