net.sf.farrago.runtime
Class FennelTransformTupleIter

java.lang.Object
  org.eigenbase.runtime.AbstractTupleIter
      net.sf.farrago.runtime.FennelAbstractTupleIter
          net.sf.farrago.runtime.FennelTransformTupleIter

All Implemented Interfaces:

TupleIter, ClosableAllocation

public class FennelTransformTupleIter
extends FennelAbstractTupleIter

FennelTransformTupleIter implements the TupleIter interfaces by reading tuples from a Fennel JavaTransformExecStream.

FennelTransformTupleIter only deals with raw byte buffers; it delegates to a FennelTupleReader object the responsibility to unmarshal individual fields.

FennelTransformTupleIter's implementation of populateBuffer() does not block.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/runtime/FennelTransformTupleIter.java#7 $

Author:

Stephan Zuercher

Nested Class Summary

Nested classes/interfaces inherited from interface org.eigenbase.runtime.TupleIter

TupleIter.NoDataReason, TupleIter.TimeoutException

Field Summary

private int	execStreamInputOrdinal
private FennelStreamHandle	inputStreamHandle
private FennelStreamGraph	streamGraph
private FennelStreamHandle	streamHandle

Fields inherited from class net.sf.farrago.runtime.FennelAbstractTupleIter

bufferAsArray, byteBuffer, tupleReader

Fields inherited from interface org.eigenbase.runtime.TupleIter

EMPTY_ITERATOR

Constructor Summary

FennelTransformTupleIter(FennelTupleReader tupleReader, FennelStreamGraph streamGraph, FennelStreamHandle streamHandle, FennelStreamHandle inputStreamHandle, int inputOrdinal, int bufferSize)
Creates a new FennelTransformTupleIter object.

Method Summary

void	closeAllocation() Closes this object.
protected int	populateBuffer() Non-blocking implementation of FennelTupleIter.populateBuffer().
void	restart() Restarts this iterator, so that a subsequent call to TupleIter.fetchNext() returns the first element in the collection being iterated.

Methods inherited from class net.sf.farrago.runtime.FennelAbstractTupleIter

fetchNext, getStatus, requestData, traceNext

Methods inherited from class org.eigenbase.runtime.AbstractTupleIter

setTimeout

Methods inherited from class java.lang.Object

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

Field Detail

execStreamInputOrdinal

private final int execStreamInputOrdinal

streamGraph

private final FennelStreamGraph streamGraph

streamHandle

private final FennelStreamHandle streamHandle

inputStreamHandle

private final FennelStreamHandle inputStreamHandle

Constructor Detail

FennelTransformTupleIter

public FennelTransformTupleIter(FennelTupleReader tupleReader,
                                FennelStreamGraph streamGraph,
                                FennelStreamHandle streamHandle,
                                FennelStreamHandle inputStreamHandle,
                                int inputOrdinal,
                                int bufferSize)

Creates a new FennelTransformTupleIter object.

Parameters:

tupleReader - FennelTupleReader to use to interpret Fennel data

streamGraph - underlying FennelStreamGraph

streamHandle - handle to underlying Fennel JavaTransformExecStream

inputStreamHandle - handle to the Fennel ExecStream that this TupleIter reads from -- used only for reset

inputOrdinal - the input stream's ordinal in the underlying JavaTransformExecStream

bufferSize - number of bytes in buffer used for fetching from Fennel

Method Detail

restart

public void restart()

Description copied from interface: TupleIter

Restarts this iterator, so that a subsequent call to TupleIter.fetchNext() returns the first element in the collection being iterated.

Specified by:

restart in interface TupleIter

Overrides:

restart in class FennelAbstractTupleIter

closeAllocation

public void closeAllocation()

Description copied from interface: ClosableAllocation

Closes this object.

populateBuffer

protected int populateBuffer()

Non-blocking implementation of FennelTupleIter.populateBuffer().

Specified by:

populateBuffer in class FennelAbstractTupleIter

Returns:

number of bytes read into FennelAbstractTupleIter.byteBuffer, 0 for end of stream, less than 0 for no data available