On Fri, Jul 1, 2011 at 5:59 PM, Alan D. Cabrera <l...@toolazydogs.com> wrote:
>
> On Jun 30, 2011, at 4:13 PM, Emmanuel Lecharny wrote:
>
>> On 6/30/11 9:52 PM, Alan D. Cabrera wrote:
>>> On Jun 30, 2011, at 2:42 AM, Ashish wrote:
>>>
>>>> <snip/>
>>
>>>> This does meet some of our requirements, but not all. We can have something
>>>> similar to this and instead of returning true/false
>>>> from Filters, we can return the next step to be executed. Something like
>>>> this
>>>>
>>>> IoFilter messageReceived(IoSession session, Object message) {
>>>> // process
>>>>
>>>> // see if just to flow with Filter Chain
>>>> return null; // or something better
>>>>
>>>> // or
>>>> // a diff message detected, calculate next filter based on some app
>>>> specific state
>>>> return calculateNextFilter(state);
>>>> }
>>>>
>>>> command is passed back to the chain and it can take care of executing the
>>>> next filter.
>>>>
>>>> Shall try something similar in sandbox and lets see how it goes :)
>>> I'm not so sure that filters should be in charge of deciding who should be
>>> called next. I don't think that how the filter stack is assembled should
>>> be leaked into the filters themselves. The filter should be solely
>>> concerned with its task and not have to decide who gets called next.
>>
>> Not sure, Alan. There are some cases where it's mandatory that a filter
>> select the next filter to execute : for instance, if your codec produces
>> more than one message, and the following processing may depend on the
>> message type. Of course, you can use a demux protocol filter (I don't
>> exactly remember the name of it, so it's from the top of my head, but we use
>> such a mechanism in ADS), but it's just one option.
>
>
> I'm hearing a state machine that's implicitly defined via what gets returned
> by that method. If this is the case would it not be better to have an
> explicitly defined state machine?
For simple cases this might "seem" like overkill but IMHO I think it's
better always to be explicit. It's clear what is happening. Surprise
Emmanuel that you did not jump for this you are Mr. State Machine :-).
Regards,
Alex
