org.apache.pig.scripting.groovy
Class GroovyAccumulatorEvalFunc

java.lang.Object
  org.apache.pig.EvalFunc<T>
      org.apache.pig.AccumulatorEvalFunc<Object>
          org.apache.pig.scripting.groovy.GroovyAccumulatorEvalFunc

All Implemented Interfaces:

Accumulator<Object>

public class GroovyAccumulatorEvalFunc
extends AccumulatorEvalFunc<Object>

Nested Class Summary

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

GroovyAccumulatorEvalFunc(String path, String namespace, String accumulatorMethod, String accumulateMethod, String getValueMethod, String cleanupMethod)

Method Summary

void	accumulate(Tuple b) Pass tuples to the UDF.
void	cleanup() Called after getValue() to prepare processing for next key.
Object	getValue() Called when all tuples from current key have been passed to accumulate.
Schema	outputSchema(Schema input) Report the schema of the output of this UDF.

Methods inherited from class org.apache.pig.AccumulatorEvalFunc

exec

Methods inherited from class org.apache.pig.EvalFunc

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

GroovyAccumulatorEvalFunc

public GroovyAccumulatorEvalFunc(String path,
                                 String namespace,
                                 String accumulatorMethod,
                                 String accumulateMethod,
                                 String getValueMethod,
                                 String cleanupMethod)
                          throws IOException

Throws:

IOException

Method Detail

accumulate

public void accumulate(Tuple b)
                throws IOException

Description copied from interface: Accumulator

Pass tuples to the UDF.

Specified by:

accumulate in interface Accumulator<Object>

Specified by:

accumulate in class AccumulatorEvalFunc<Object>

Parameters:

b - A tuple containing a single field, which is a bag. The bag will contain the set of tuples being passed to the UDF in this iteration.

Throws:

IOException

cleanup

public void cleanup()

Description copied from interface: Accumulator

Called after getValue() to prepare processing for next key.

Specified by:

cleanup in interface Accumulator<Object>

Specified by:

cleanup in class AccumulatorEvalFunc<Object>

getValue

public Object getValue()

Description copied from interface: Accumulator

Called when all tuples from current key have been passed to accumulate.

Specified by:

getValue in interface Accumulator<Object>

Specified by:

getValue in class AccumulatorEvalFunc<Object>

Returns:

the value for the UDF for this key.

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