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

Class AbstractIteratorHandler<T,I,N>

java.lang.Object

de.aristaflow.ilm.model.common.collection.AbstractIteratorHandler<T,I,N>

Type Parameters:

T - The type of the handled iterators.

I - The type of the initial data provided when requesting the iterator.

N - The type of the data when iterating.

Direct Known Subclasses:

IncWorklistHandler, IncWorklistUpdateHandler, RemoteIteratorHandler

public class AbstractIteratorHandler<T,I,N>
extends Object

This class handles provides the basic means for handling iterators. This includes the data structure containing the iterators, runnables for removing iterators from the data structure and dropping them as well as the corresponding scheduled executor service.
Usually the iterators need some additional meta data. Use a small wrapper for this and let this class handle the wrapper classes.

Iterators and their handling classes are generic classes whereas the generic type specifies the elements of the iterator. However, Java's type system may become a problem for other languages. Therefore the ILM removes the generic type and makes it explicit. At runtime this handler needs to create and provide the concrete types without generics, so instantiation is delegated to Suppliers provided when instantiating this handler.

Due to the API of iterators being rather specific, this class is a mere sketch and a lot of logic has to happen in subclasses.

See Also:

RemoteIterator, IncrementalWorklist, IncrementalWorklistUpdate

Field Summary

Fields

Modifier and Type	Field	Description
protected long	aliveTimeExtension	The time in milliseconds to extend the alive time of the iterator implicitly.
protected Supplier<N>	dataCreator	The creator for data provided when iterating.
protected Supplier<I>	initDataCreator	The creator for data provided initially when requesting the iterator.
protected Map<UUID,T>	iterators	The map containing iterators while they are active.
protected ScheduledExecutorService	removerService	The scheduler service which drops and removes all registered iterators after their alive time has elapsed from this handler.

Constructor Summary

Constructors

Constructor	Description
AbstractIteratorHandler(Supplier<I> initDataCreator, Supplier<N> dataCreator, long aliveTimeExtension, String name, LogService logService)	Creates a new iteration handler.

Method Summary

Modifier and Type	Method	Description
protected T	getIterator(UUID iteratorId)	Gets the iterator (with metadata) with the designated ID.
void	shutdown()	Shuts the executor service down and waits for the termination of running threads.

Methods inherited from class java.lang.Object

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

Field Detail

iterators

protected final Map<UUID,T> iterators

The map containing iterators while they are active. The key is a random UUID identifying the iterator.

removerService

protected final ScheduledExecutorService removerService

The scheduler service which drops and removes all registered iterators after their alive time has elapsed from this handler.

initDataCreator

protected final Supplier<I> initDataCreator

The creator for data provided initially when requesting the iterator.

dataCreator

protected final Supplier<N> dataCreator

The creator for data provided when iterating.

aliveTimeExtension

protected final long aliveTimeExtension

The time in milliseconds to extend the alive time of the iterator implicitly. Iterators with explicit alive time handling may ignore this.

Constructor Detail

AbstractIteratorHandler

public AbstractIteratorHandler(Supplier<I> initDataCreator,
                               Supplier<N> dataCreator,
                               long aliveTimeExtension,
                               String name,
                               LogService logService)

Creates a new iteration handler.

Parameters:

initDataCreator - The creator for data provided initially when requesting the iterator.

dataCreator - The creator for data provided when iterating.

aliveTimeExtension - The time in milliseconds to extend the alive time of the iterator implicitly.

name - The name for the executor.

logService - The log service to retrieve the logger for the executor from.

Method Detail

shutdown

public void shutdown()

Shuts the executor service down and waits for the termination of running threads.

getIterator

protected T getIterator(UUID iteratorId)

Gets the iterator (with metadata) with the designated ID.

Parameters:

iteratorId - The ID of the iterator with metadata to retrieve.

Returns:

The iterator (with metadata) with the designated ID.

Throws:

IllegalArgumentException - If the designated ID does not refer to an iterator known by this handler, an IllegalArgumentException will be thrown.