org.apache.pig.builtin

Class HiveUDTF

java.lang.Object

org.apache.pig.EvalFunc<Object>

org.apache.pig.builtin.HiveUDTF

public class HiveUDTF
extends EvalFunc<Object>

Use Hive GenericUDTF. Example: define explode HiveUDTF('explode'); A = load 'mydata' as (a0:{(b0:chararray)}); B = foreach A generate flatten(explode(a0));

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	HiveUDFBase.ConstantObjectInspectInfo
protected static class	HiveUDFBase.HiveReporter A constant of Reporter type that does nothing.

Nested classes/interfaces inherited from class org.apache.pig.EvalFunc

EvalFunc.SchemaType

Field Summary

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

Constructors

Constructor and Description
HiveUDTF(String funcName)
HiveUDTF(String funcName, String params)

Method Summary

Methods

Modifier and Type	Method and Description
Object	exec(Tuple input) This callback method must be implemented by all subclasses.
protected static String	getErrorMessage(Class c)
List<String>	getShipFiles() Allow a UDF to specify a list of local files it would like placed in the distributed cache.
protected static org.apache.hadoop.hive.ql.exec.MapredContext	instantiateMapredContext()
boolean	needEndOfAllInputProcessing()
Schema	outputSchema(Schema input) Report the schema of the output of this UDF.
protected static Class	resolveFunc(String funcName)
void	setEndOfAllInput(boolean endOfAllInput)

Methods inherited from class org.apache.pig.EvalFunc

allowCompileTimeCalculation, finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, getSchemaType, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn

Methods inherited from class java.lang.Object

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

Constructor Detail

HiveUDTF

public HiveUDTF(String funcName)
         throws InstantiationException,
                IllegalAccessException,
                IOException

Throws:

InstantiationException

IllegalAccessException

IOException

HiveUDTF

public HiveUDTF(String funcName,
        String params)
         throws InstantiationException,
                IllegalAccessException,
                IOException

Throws:

InstantiationException

IllegalAccessException

IOException

Method Detail

exec

public Object exec(Tuple input)
            throws IOException

Description copied from class: EvalFunc

This callback method must be implemented by all subclasses. This is the method that will be invoked on every Tuple of a given dataset. Since the dataset may be divided up in a variety of ways the programmer should not make assumptions about state that is maintained between invocations of this method.

Specified by:

exec in class EvalFunc<Object>

Parameters:

input - the Tuple to be processed.

Returns:

result, of type T.

Throws:

IOException

outputSchema

public Schema outputSchema(Schema input)

Description copied from class: EvalFunc

Report the schema of the output of this UDF. Pig will make use of this in error checking, optimization, and planning. The schema of input data to this UDF is provided.

The default implementation interprets the OutputSchema annotation, if one is present. Otherwise, it returns null (no known output schema).

Overrides:

outputSchema in class EvalFunc<Object>

Parameters:

input - Schema of the input

Returns:

Schema of the output

needEndOfAllInputProcessing

public boolean needEndOfAllInputProcessing()

Overrides:

needEndOfAllInputProcessing in class EvalFunc<Object>

setEndOfAllInput

public void setEndOfAllInput(boolean endOfAllInput)

Overrides:

setEndOfAllInput in class EvalFunc<Object>

resolveFunc

protected static Class resolveFunc(String funcName)
                            throws IOException

Throws:

IOException

instantiateMapredContext

protected static org.apache.hadoop.hive.ql.exec.MapredContext instantiateMapredContext()

getShipFiles

public List<String> getShipFiles()

Description copied from class: EvalFunc

Allow a UDF to specify a list of local files it would like placed in the distributed cache. These files will be put in the cache for every job the UDF is used in. Check for FuncUtils for utility function to facilitate it The default implementation returns null.

Overrides:

getShipFiles in class EvalFunc<Object>

Returns:

A list of files

getErrorMessage

protected static String getErrorMessage(Class c)