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

Class GenericUDFUtils.ReturnObjectInspectorResolver

java.lang.Object

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

Enclosing class:

GenericUDFUtils

public static class GenericUDFUtils.ReturnObjectInspectorResolver
extends java.lang.Object

This class helps to find the return ObjectInspector for a GenericUDF. In many cases like CASE and IF, the GenericUDF is returning a value out of several possibilities. However these possibilities may not always have the same ObjectInspector. This class will help detect whether all possibilities have exactly the same ObjectInspector. If not, then we need to convert the Objects to the same ObjectInspector. A special case is when some values are constant NULL. In this case we can use the same ObjectInspector.

Constructor Summary

Constructors

Constructor and Description
ReturnObjectInspectorResolver()
ReturnObjectInspectorResolver(boolean allowTypeConversion)

Method Summary

Modifier and Type	Method and Description
java.lang.Object	convertIfNecessary(java.lang.Object o, ObjectInspector oi) Convert the return Object if necessary (when the ObjectInspectors of different possibilities are not all the same).
ObjectInspector	get() Returns the ObjectInspector of the return value.
boolean	update(ObjectInspector oi) Update returnObjectInspector and valueInspectorsAreTheSame based on the ObjectInspector seen.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReturnObjectInspectorResolver

public ReturnObjectInspectorResolver()

ReturnObjectInspectorResolver

public ReturnObjectInspectorResolver(boolean allowTypeConversion)

Method Detail

update

public boolean update(ObjectInspector oi)
               throws UDFArgumentTypeException

Update returnObjectInspector and valueInspectorsAreTheSame based on the ObjectInspector seen.

Returns:

false if there is a type mismatch

Throws:

UDFArgumentTypeException

get

public ObjectInspector get()

Returns the ObjectInspector of the return value.

convertIfNecessary

public java.lang.Object convertIfNecessary(java.lang.Object o,
                                           ObjectInspector oi)

Convert the return Object if necessary (when the ObjectInspectors of different possibilities are not all the same).