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

Class GenericUDFWhen

java.lang.Object

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

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

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class GenericUDFWhen
extends GenericUDF

GenericUDF Class for SQL construct "CASE a WHEN b THEN c [ELSE f] END". NOTES: 1. a and b should have the same TypeInfo, or an exception will be thrown. 2. c and f should have the same TypeInfo, or an exception will be thrown.

Nested Class Summary

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

GenericUDF.DeferredJavaObject, GenericUDF.DeferredObject

Constructor Summary

Constructors

Constructor and Description
GenericUDFWhen()

Method Summary

Modifier and Type	Method and Description
java.lang.Object	evaluate(GenericUDF.DeferredObject[] arguments) Evaluate the GenericUDF with the arguments.
java.lang.String	getDisplayString(java.lang.String[] children) Get the String to be displayed in explain.
ObjectInspector	initialize(ObjectInspector[] arguments) Initialize this GenericUDF.

Methods inherited from class org.apache.hadoop.hive.ql.udf.generic.GenericUDF

close, configure, getRequiredFiles, getRequiredJars, initializeAndFoldConstants

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericUDFWhen

public GenericUDFWhen()

Method Detail

initialize

public ObjectInspector initialize(ObjectInspector[] arguments)
                           throws UDFArgumentTypeException

Description copied from class: GenericUDF

Initialize this GenericUDF. This will be called once and only once per GenericUDF instance.

Specified by:

initialize in class GenericUDF

Parameters:

arguments - The ObjectInspector for the arguments

Returns:

The ObjectInspector for the return value

Throws:

UDFArgumentTypeException

evaluate

public java.lang.Object evaluate(GenericUDF.DeferredObject[] arguments)
                          throws HiveException

Description copied from class: GenericUDF

Evaluate the GenericUDF with the arguments.

Specified by:

evaluate in class GenericUDF

Parameters:

arguments - The arguments as DeferedObject, use DeferedObject.get() to get the actual argument Object. The Objects can be inspected by the ObjectInspectors passed in the initialize call.

Returns:

The

Throws:

HiveException

getDisplayString

public java.lang.String getDisplayString(java.lang.String[] children)

Description copied from class: GenericUDF

Get the String to be displayed in explain.

Specified by:

getDisplayString in class GenericUDF