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

Class GenericUDTF

java.lang.Object

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

Direct Known Subclasses:

GenericUDTFExplode, GenericUDTFInline, GenericUDTFJSONTuple, GenericUDTFParseUrlTuple, GenericUDTFStack

public abstract class GenericUDTF
extends java.lang.Object

A Generic User-defined Table Generating Function (UDTF) Generates a variable number of output rows for a single input row. Useful for explode(array)...

Constructor Summary

Constructors

Constructor and Description
GenericUDTF()

Method Summary

Modifier and Type	Method and Description
abstract void	close() Called to notify the UDTF that there are no more rows to process.
void	configure(MapredContext mapredContext) Additionally setup GenericUDTF with MapredContext before initializing.
protected void	forward(java.lang.Object o) Passes an output row to the collector.
abstract StructObjectInspector	initialize(ObjectInspector[] argOIs) Initialize this GenericUDTF.
abstract void	process(java.lang.Object[] args) Give a set of arguments for the UDTF to process.
void	setCollector(Collector collector) Associates a collector with this UDTF.

Methods inherited from class java.lang.Object

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

Constructor Detail

GenericUDTF

public GenericUDTF()

Method Detail

configure

public void configure(MapredContext mapredContext)

Additionally setup GenericUDTF with MapredContext before initializing. This is only called in runtime of MapRedTask.

Parameters:

context - context

initialize

public abstract StructObjectInspector initialize(ObjectInspector[] argOIs)
                                          throws UDFArgumentException

Initialize this GenericUDTF. This will be called only once per instance.

Parameters:

argOIs - An array of ObjectInspectors for the arguments

Returns:

A StructObjectInspector for output. The output struct represents a row of the table where the fields of the stuct are the columns. The field names are unimportant as they will be overridden by user supplied column aliases.

Throws:

UDFArgumentException

process

public abstract void process(java.lang.Object[] args)
                      throws HiveException

Give a set of arguments for the UDTF to process.

Parameters:

args - object array of arguments

Throws:

HiveException

close

public abstract void close()
                    throws HiveException

Called to notify the UDTF that there are no more rows to process. Clean up code or additional forward() calls can be made here.

Throws:

HiveException

setCollector

public final void setCollector(Collector collector)

Associates a collector with this UDTF. Can't be specified in the constructor as the UDTF may be initialized before the collector has been constructed.

Parameters:

collector -

forward

protected final void forward(java.lang.Object o)
                      throws HiveException

Passes an output row to the collector.

Parameters:

o -

Throws:

HiveException