Emperor wrote:
>>-----Urspr�ngliche Nachricht-----
>>Von: Berin Loritsch [mailto:[EMAIL PROTECTED]]
>>Gesendet: Montag, 25. Februar 2002 14:17
>>An: Avalon Developers List
>>Betreff: Re: event queue improvment
>>
>>
>>Emperor wrote:
>>
>>>hi,
>>>
>>>I had a look at the event queue implementation and I think a method
>>>that blocks until n elements can be enqueued could be very useful.
>>>
>>>For example, you could have a full queue of requests and an
>>>interceptor that adds requests to the queue. Using the
>>>
>>block method,
>>
>>>the interceptor would stop intercepting request when the queue is
>>>full, which would be the logical behavior of an overloaded system.
>>>
>>
>>Queue is an interface. If you want an implementation that
>>takes care of this semantic, more power to you. I don't
>>think it should be *Yet another method*.
>>
>>In a complex event routing system, you really don't want
>>blocking at all. The reason is that depending on your thread
>>manager, you may have fewer threads than Queues. In such a
>>case it is more efficient to use those finite amount of
>>threads to pull the events in a non-blocking manner. If
>>there are no events, move on to the next queue.
>>
>>
>
> I agree that blocking is bad in normal situations but I'm talking about
> event routing on an overloaded system (see example). How should the
> sender
> react when the queue is full? I think then blocking is the best method.
Question: are you talking about blocking on enqueue() or dequeue()?
Honestly, I can't tell from your example.
If a queue is full (which can only happen on a Fixed Size Queue), then
the Queue throws an Exception placing some backpressure at that point.
However, it is possible to have a ThreadPool per queue. Once some
threshold on the Queue is reached, an aditional thread is initiated.
That way if you need three threads to maintain smooth operation, it is
there waiting for you.
When you talk about blocking, it is usually on the dequeue() operation.
In otherwords, we want to wait up to X milliseconds for events to show
up in the queue.
I would seriously -1 a block on the enqueue operation.
--
"They that give up essential liberty to obtain a little temporary safety
deserve neither liberty nor safety."
- Benjamin Franklin
--
To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]>
For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
