Package de.aristaflow.ilm.model.common.collection

Class IteratorWrapper<T>

java.lang.Object

de.aristaflow.ilm.model.common.collection.IteratorWrapper<T>

Type Parameters:

T - The type of iterator handled by this iterator wrapper.

All Implemented Interfaces:

Runnable

public class IteratorWrapper<T>
extends Object
implements Runnable

A wrapper for an iterator and also a runnable for removing the iterator from an AbstractIteratorHandler. Note that a ScheduledExecutorService does not allow to remove a scheduled runnable. Therefore this remover checks the remaining alive time of its iterator and either removes it or reschedules itself for another run.
As soon as the alive time elapses, this wrapper removes the iterator from the data structure and drops it. Dropping may fail in case the underlying iterator has its own drop mechanism.

Field Summary

Fields

Modifier and Type	Field	Description
protected Consumer<T>	dropper	The method called for dropping the iterator.
protected long	dropTime	The time the iterator is dropped.
protected T	iterator	The wrapped iterator of this wrapper.
protected UUID	iteratorId	The ID assigned to the corresponding iterator.
protected Map<UUID,?>	iterators	The data structure providing the current iterators indexed by the assigned iterator ID.
protected long	remAliveTimeExtension	The time in milliseconds the alive time is extended if requested.
protected ScheduledExecutorService	removerService	The scheduled executor service executing this wrapper.

Constructor Summary

Constructors

Constructor	Description
IteratorWrapper(UUID iteratorId, T iterator, long remAliveTimeExtension, Consumer<T> dropper, Map<UUID,?> iterators, ScheduledExecutorService removerService)	Creates a new wrapper for the designated iterator having the designated ID.

Method Summary

Modifier and Type	Method	Description
long	extendRemainingAliveTime()	Extends the remaining alive time by the usual period for extension and returns the new remaining time.
T	getIterator()	Gets the wrapped iterator.
protected long	getRemainingAliveTime()	Gets the remaining alive time in milliseconds before this wrapper will removed and possibly drop the iterator.
void	run()

Methods inherited from class java.lang.Object

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

Field Detail

iteratorId

protected final UUID iteratorId

The ID assigned to the corresponding iterator.

iterator

protected final T iterator

The wrapped iterator of this wrapper.

remAliveTimeExtension

protected final long remAliveTimeExtension

The time in milliseconds the alive time is extended if requested.

dropTime

protected long dropTime

The time the iterator is dropped. This may not be used but overridden by the drop time of the underlying iterator.

dropper

protected final Consumer<T> dropper

The method called for dropping the iterator. If this is null, this wrapper will not drop the iterator but just remove it from the data structure.

iterators

protected final Map<UUID,?> iterators

The data structure providing the current iterators indexed by the assigned iterator ID. This is just for removing iterators of which the alive time has elapsed.

removerService

protected final ScheduledExecutorService removerService

The scheduled executor service executing this wrapper. This is used for re-scheduling in case the alive time has been extended the time the wrapper is executed.

Constructor Detail

IteratorWrapper

public IteratorWrapper(UUID iteratorId,
                       T iterator,
                       long remAliveTimeExtension,
                       Consumer<T> dropper,
                       Map<UUID,?> iterators,
                       ScheduledExecutorService removerService)

Creates a new wrapper for the designated iterator having the designated ID.

Parameters:

iteratorId - The ID of the iterator.

iterator - The iterator to wrap.

remAliveTimeExtension - The time in milliseconds the alive time is extended if requested.

dropper - The method called for dropping the iterator. If this is null, this wrapper will not drop the iterator but just remove it from the data structure.

iterators - The data structure providing the current iterators indexed by the assigned iterator ID. This is just for removing iterators of which the alive time has elapsed.

removerService - The scheduled executor service executing this wrapper. This is used for re-scheduling in case the alive time has been extended the time the wrapper is executed.

Method Detail

getRemainingAliveTime

protected long getRemainingAliveTime()

Gets the remaining alive time in milliseconds before this wrapper will removed and possibly drop the iterator. The alive time may be extended in the future.
To use the alive time of the underlying iterator, override this method appropriately.

Returns:

The remaining alive time in milliseconds before this wrapper will removed and possibly drop the iterator.

extendRemainingAliveTime

public long extendRemainingAliveTime()

Extends the remaining alive time by the usual period for extension and returns the new remaining time.
To extend the alive time of the underlying iterator, override this method appropriately.

Returns:

The remaining alive time in milliseconds after extending the alive time of this wrapper and/or the underlying iterator.

getIterator

public T getIterator()

Gets the wrapped iterator.

Returns:

The wrapped iterator.

run

public void run()

Specified by:

run in interface Runnable