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 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

GenericUDFUtils.ReturnObjectInspectorResolver()

GenericUDFUtils.ReturnObjectInspectorResolver(boolean allowTypeConversion)

Method Summary

Object	convertIfNecessary(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

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

Constructor Detail

GenericUDFUtils.ReturnObjectInspectorResolver

public GenericUDFUtils.ReturnObjectInspectorResolver()

GenericUDFUtils.ReturnObjectInspectorResolver

public GenericUDFUtils.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 Object convertIfNecessary(Object o,
                                 ObjectInspector oi)

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