org.apache.pig.scripting.jruby

Class JrubyAlgebraicEvalFunc.Initial

java.lang.Object

org.apache.pig.EvalFunc<T>

org.apache.pig.scripting.jruby.JrubyAlgebraicEvalFunc.AlgebraicFunctionWrapper<Tuple>

org.apache.pig.scripting.jruby.JrubyAlgebraicEvalFunc.Initial

Enclosing class:

JrubyAlgebraicEvalFunc<T>

public static class JrubyAlgebraicEvalFunc.Initial
extends JrubyAlgebraicEvalFunc.AlgebraicFunctionWrapper<Tuple>

This class invokes the initial method on the given Ruby class. As a courtesy to the user, it unwraps the DataBag that is given to Initial and passes Ruby just the first Tuple that it contains, as the contract for the Initial function in Algebraic is that it is given a DataBag with one and only one Tuple. Finally, it wraps the Ruby output in a Tuple.

Nested Class Summary

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

EvalFunc.SchemaType

Field Summary

Fields inherited from class org.apache.pig.scripting.jruby.JrubyAlgebraicEvalFunc.AlgebraicFunctionWrapper

isInitialized, receiver, stage

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

Constructors

Constructor and Description
Initial()
Initial(java.lang.String fileName, java.lang.String functionName)

Method Summary

Modifier and Type	Method and Description
Tuple	exec(Tuple input) This callback method must be implemented by all subclasses.

Methods inherited from class org.apache.pig.scripting.jruby.JrubyAlgebraicEvalFunc.AlgebraicFunctionWrapper

getFileName, getFunctionName, getReceiver, getStage, initialize, isInitialized

Methods inherited from class org.apache.pig.EvalFunc

addCredentials, allowCompileTimeCalculation, finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLoadCaster, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, getSchemaType, getShipFiles, isAsynchronous, needEndOfAllInputProcessing, outputSchema, progress, setEndOfAllInput, 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

Initial

public Initial()

Initial

public Initial(java.lang.String fileName,
               java.lang.String functionName)

Method Detail

exec

public Tuple exec(Tuple input)
           throws java.io.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 JrubyAlgebraicEvalFunc.AlgebraicFunctionWrapper<Tuple>

Parameters:

input - the Tuple to be processed.

Returns:

result, of type T.

Throws:

java.io.IOException