net.sf.farrago.runtime
Class FarragoTransformImpl

java.lang.Object
  net.sf.farrago.runtime.FarragoTransformImpl

All Implemented Interfaces:

FarragoTransform

Direct Known Subclasses:

FarragoGeneratedCodeExamples.ExampleGeneratedFarragoTransform

public abstract class FarragoTransformImpl
extends Object
implements FarragoTransform

FarragoTransformImpl provides a base class for generated implementations of FarragoTransform.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/runtime/FarragoTransformImpl.java#13 $

Author:

Julian Hyde, Stephan Zuercher

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.farrago.runtime.FarragoTransform

FarragoTransform.InputBinding

Field Summary

private Object	next
private TupleIter	tupleIter
private FennelTupleWriter	tupleWriter

Constructor Summary

FarragoTransformImpl()

Method Summary

int	execute(ByteBuffer outputBuffer, long quantum) Execute this transform.
protected TupleIter	getTupleIter() for named subclasses, not for generated transforms
protected void	init(FennelTupleWriter tupleWriter, TupleIter tupleIter) Initialze this FarragoTransformImpl.
void	restart() Restart the underlying tupleIter.
void	setInputFetchTimeout(long msec) Sets a timeout for fetching an input row.

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.farrago.runtime.FarragoTransform

init

Field Detail

tupleIter

private TupleIter tupleIter

tupleWriter

private FennelTupleWriter tupleWriter

next

private Object next

Constructor Detail

FarragoTransformImpl

public FarragoTransformImpl()

Method Detail

init

protected void init(FennelTupleWriter tupleWriter,
                    TupleIter tupleIter)

Initialze this FarragoTransformImpl. Generated FarragoTransform implementations should pass their generated FennelTupleWriter and TupleIter implementations here. A subclass (not an anonymous subclass) may pass null for tupleWriter or tupleIter iff it has a different way to read or write its data and iff it overrides execute(java.nio.ByteBuffer, long) and restart() as appropriate.

Parameters:

tupleWriter - FennelTupleWriter that can marshal this transform's output tuple format.

tupleIter - TupleIter that performs this transform's work

getTupleIter

protected TupleIter getTupleIter()

for named subclasses, not for generated transforms

setInputFetchTimeout

public void setInputFetchTimeout(long msec)

Description copied from interface: FarragoTransform

Sets a timeout for fetching an input row. 0 means poll, infinity (ie Long.MAX_VALUE) means block. The default is to block;

Specified by:

setInputFetchTimeout in interface FarragoTransform

execute

public int execute(ByteBuffer outputBuffer,
                   long quantum)

Execute this transform. Execution continues until the underlying tupleIter returns END_OF_DATA or UNDERFLOW or until the underlying tupleWriter can no longer marshal tuples into the output buffer.

Specified by:

execute in interface FarragoTransform

Parameters:

outputBuffer - output ByteBuffer, written to via tupleWriter

quantum - the maximum number of tuples to process before returning

Returns:

number of bytes marshaled into outputBuffer; 0 on END_OF_DATA; -1 on UNDERFLOW

restart

public void restart()

Restart the underlying tupleIter.

Specified by:

restart in interface FarragoTransform