org.eigenbase.runtime
Class AbstractTupleIter

java.lang.Object
  org.eigenbase.runtime.AbstractTupleIter

All Implemented Interfaces:

TupleIter, ClosableAllocation

Direct Known Subclasses:

CompoundParallelTupleIter, CompoundTupleIter.Test.BoxTupleIter, FennelAbstractTupleIter, MedMockTupleIter, RestartableCollectionTupleIter, RestartableIteratorTupleIter, ResultSetTupleIter, TimeoutQueueTupleIterTest.TickIterator

public abstract class AbstractTupleIter
extends Object
implements TupleIter

A base class for implementations of TupleIter, with default implementations of some of its methods.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/runtime/AbstractTupleIter.java#4 $

Author:

Marc Berkowitz

Nested Class Summary

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

TupleIter.NoDataReason, TupleIter.TimeoutException

Field Summary

Fields inherited from interface org.eigenbase.runtime.TupleIter

EMPTY_ITERATOR

Constructor Summary

AbstractTupleIter()

Method Summary

void	restart() Restarts this iterator, so that a subsequent call to TupleIter.fetchNext() returns the first element in the collection being iterated.
boolean	setTimeout(long timeout, boolean asUnderflow) Sets a timeout for TupleIter.fetchNext(); (optional operation).

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eigenbase.runtime.TupleIter

fetchNext

Methods inherited from interface org.eigenbase.util.ClosableAllocation

closeAllocation

Constructor Detail

AbstractTupleIter

public AbstractTupleIter()

Method Detail

setTimeout

public boolean setTimeout(long timeout,
                          boolean asUnderflow)

Description copied from interface: TupleIter

Sets a timeout for TupleIter.fetchNext(); (optional operation). Not all implementing classes support a timeout. For those that do, this method provides a common interface, For those that do not, the adapter TimeoutQueueTupleIter puts a timeout queue on top.

Specified by:

setTimeout in interface TupleIter

Parameters:

timeout - in milliseconds. 0 means poll, infinity means block.

asUnderflow - true means indicate timeout by returning TupleIter.NoDataReason.UNDERFLOW; false means throw TupleIter.TimeoutException on a timeout.

Returns:

true if the timeout was set, false if the implementing class does not support a timeout.

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