Grizzly NIO 5.0.2 · org.glassfish.grizzly.comet.concurrent.DefaultConcurrentCometHandler

We queue events in each CometHandler to lower the probability that slow or massive IO for one CometHandler severely delays events to others.

only streaming mode can benefit from buffering messages like this.
only 1 thread at a time is allowed to do IO, other threads put events in the queue and return to the thread pool.

a thread initially calls enqueueEvent and stay there until there are no more events in the queue, calling the onEVent method in synchronized context for each Event.

on IOE in onEvent we terminate.
we have a limit, to keep memory usage under control.

if queue limit is reached onQueueFull is called, and then we terminate.

whats not optimal is that a worker thread is sticky to the client depending upon available events in the handlers local queue, that can in theory allow a few clients to block all threads for extended time.
that effect can make this implementation unusable depending on the scenario, its not a perfect design be any means.
The potential improvement is that only 1 worker thread is tied up to a client instead of several being blocked by synchronized io wait for one CometHandler .

Field Summary

Modifier and Type	Field and Description
private CometContext<E>	context
protected static final Logger	logger
protected final Queue<CometEvent<E>>	messageQueue todo replace with non array copying list for non resizing add situations, using internal index to keep track of state , not a linked list, it has too much overhead and eats memory.
private final int	messageQueueLimit max number of events to locally queue for this CometHandler.
private int	queueSize current queue size
private boolean	readyForWork true means that no thread is currently active on this comet handlers queue logic
private Response	response
private boolean	shuttingDown used for preventing the worker threads from the executor event queue from adding events to the comet handlers local queue or starting IO logic after shut down.

Constructor Summary

Access	Constructor and Description
public	DefaultConcurrentCometHandler(final CometContext<E> context, final Response response)
public	DefaultConcurrentCometHandler(int messageQueueLimit)

Method Summary

Modifier and Type	Method and Description
public void	enqueueEvent(CometEvent<E> event) Queues event if another thread is currently working on this handler.
public CometContext<E>	getCometContext() Implements org.glassfish.grizzly.comet.CometHandler.getCometContext.
public Response	getResponse() Implements org.glassfish.grizzly.comet.CometHandler.getResponse.
public void	onInterrupt(CometEvent<E> event) Implements org.glassfish.grizzly.comet.CometHandler.onInterrupt. Receive `CometEvent` notification when the underlying tcp communication is resumed by Grizzly.
public void	onQueueFull(CometEvent<E> `CometEvent` event) Called in synchronized context when the comet handler's local event queue is full.
public void	onTerminate(CometEvent<E> event) Implements org.glassfish.grizzly.comet.CometHandler.onTerminate. Receive `CometEvent` notification when the response is resumed by a `CometHandler` or by the `CometContext` default impl calls terminate()
public void	setCometContext(final CometContext<E> context) Implements org.glassfish.grizzly.comet.CometHandler.setCometContext.
public void	setResponse(final Response response) Implements org.glassfish.grizzly.comet.CometHandler.setResponse.
protected void	terminate()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

context	back to summary
private CometContext<E> context

logger	back to summary
protected static final Logger logger

messageQueue	back to summary
protected final Queue<CometEvent<E>> messageQueue todo replace with non array copying list for non resizing add situations, using internal index to keep track of state , not a linked list, it has too much overhead and eats memory.

messageQueueLimit	back to summary
private final int messageQueueLimit max number of events to locally queue for this CometHandler. (a global event queue normally exists in form of a thread pool too)

queueSize	back to summary
private int queueSize current queue size

readyForWork	back to summary
private boolean readyForWork true means that no thread is currently active on this comet handlers queue logic

response	back to summary
private Response response

shuttingDown	back to summary
private boolean shuttingDown used for preventing the worker threads from the executor event queue from adding events to the comet handlers local queue or starting IO logic after shut down.

Constructor Detail

DefaultConcurrentCometHandler	back to summary
public DefaultConcurrentCometHandler(final CometContext<E> context, final Response response)

DefaultConcurrentCometHandler	back to summary
public DefaultConcurrentCometHandler(int messageQueueLimit)

Method Detail

enqueueEvent	back to summary
public void enqueueEvent(CometEvent<E> event) throws IOException Queues event if another thread is currently working on this handler. The first thread to start working will keep doing so until there are no further events in the internal queue.

getCometContext	back to summary
public CometContext<E> getCometContext() Implements org.glassfish.grizzly.comet.CometHandler.getCometContext. Annotations @Override

getCometContext

back to summary

public CometContext<E> getCometContext()

Implements org.glassfish.grizzly.comet.CometHandler.getCometContext.

Annotations

@Override

getResponse	back to summary
public Response getResponse() Implements org.glassfish.grizzly.comet.CometHandler.getResponse. Annotations @Override

getResponse

back to summary

public Response getResponse()

Implements org.glassfish.grizzly.comet.CometHandler.getResponse.

Annotations

@Override

onInterrupt back to summary

onInterrupt	back to summary
public void onInterrupt(CometEvent<E> event) throws IOException Implements org.glassfish.grizzly.comet.CometHandler.onInterrupt. Doc from org.glassfish.grizzly.comet.CometHandler.onInterrupt. Receive `CometEvent` notification when the underlying tcp communication is resumed by Grizzly. This happens when the `CometContext#setExpirationDelay` expires or when the remote client close the connection. default impl calls terminate() Annotations @Override

public void onInterrupt(CometEvent<E> event) throws IOException

Implements org.glassfish.grizzly.comet.CometHandler.onInterrupt.

Doc from org.glassfish.grizzly.comet.CometHandler.onInterrupt.

Receive CometEvent notification when the underlying tcp communication is resumed by Grizzly. This happens when the CometContext#setExpirationDelay expires or when the remote client close the connection.
default impl calls terminate()

Annotations

@Override

onQueueFull back to summary

onQueueFull	back to summary
public void onQueueFull(CometEvent<E> event) throws IOException Called in synchronized context when the comet handler's local event queue is full. default impl resumes the comet handler Parameters event:CometEvent<E> `CometEvent`

public void onQueueFull(CometEvent<E> event) throws IOException

Called in synchronized context when the comet handler's local event queue is full.
default impl resumes the comet handler

Parameters

event:CometEvent<E>: CometEvent

onTerminate back to summary

onTerminate	back to summary
public void onTerminate(CometEvent<E> event) throws IOException Implements org.glassfish.grizzly.comet.CometHandler.onTerminate. Doc from org.glassfish.grizzly.comet.CometHandler.onTerminate. Receive `CometEvent` notification when the response is resumed by a `CometHandler` or by the `CometContext` default impl calls terminate() Annotations @Override

public void onTerminate(CometEvent<E> event) throws IOException

Implements org.glassfish.grizzly.comet.CometHandler.onTerminate.

Doc from org.glassfish.grizzly.comet.CometHandler.onTerminate.

Receive CometEvent notification when the response is resumed by a CometHandler or by the CometContext
default impl calls terminate()

Annotations

@Override

setCometContext	back to summary
public void setCometContext(final CometContext<E> context) Implements org.glassfish.grizzly.comet.CometHandler.setCometContext. Annotations @Override

setCometContext

back to summary

public void setCometContext(final CometContext<E> context)

Implements org.glassfish.grizzly.comet.CometHandler.setCometContext.

Annotations