Jon:
Another technique could be to define a timeout in the server, after
which the server shuts down (drops its connection to the database).
Something like:
* each request sent to the server will cause the server code to:
1. check whether a prior alarm object (see step #4 below) was
created, if so, cancel the alarm,
2. fetch the received request,
3. carry out the request,
4. create a new alarm object which will send the shutdown
request to the server (e.g. after
one/five/ten/60/...whatever-you-think-appropriate minutes),
unless the currently handled request is the shutdown request.
Once the server has stopped, it may still be the case that it should
re-establish its services, if you keep on accepting requests. If so you
would create a server object, but not establish a connection to the
RDBMS. Then, when the server object receives a request, it will check
whether a connection to the database is active, and if so uses it,
otherwise it establishes a new connection to carry out the request, and
afterwards will keep the connection open for the given timeout period.
HTH,
---rony
On 02.04.2011 16:03, Sahananda (Jon) Wolfers wrote:
>
> I have a question, and I hope it is ok to ask it here.
>
> It has been brought up by my struggle to move my work to 4.0, but if
> solved for me could benefit many people.
>
>
>
> My specific problem is about managing to use rexx/sql with ooRexx 4.0
> in a multithreaded environment, but it might b better if I ask the
> list a more general question.
>
>
>
> That is, where one has to provide one’s applications with a service
> that continuously runs, what is the best way to set it up, use it and
> tear it down. This question has become more important in 4.0, because
> there used to be a loophole in ooDialog that allowed one to run
> methods on the ‘main’ thread of a dialog. Now that has gone, it needs
> to be done properly.
>
>
>
> So for me, because rexx\sql needs to run on the thread that the
> library was loaded on, I have built a little server, I queue message
> objects on the server, and it performs them on the correct thread.
> That all works very well. My problem pertains to how to set it up
> when it is first needed, and tear it down when it is finished with.
>
>
>
> I can set it up and start it running, by doing so in the CLASS INIT
> method. This means that the first script that includes the server
> class in a ::REQUIRES directive loads the rexx\sql libraries and kicks
> off the server.
>
>
>
> Subsequent scripts may be loaded which ‘require’ the server class, and
> it is there and running.
>
>
>
> However, when all the client scripts have finished and terminated, the
> server is still sitting there all alone running, and my interpreter
> instance won’t terminate.
>
>
>
> Is there some mechanism by which the server can know that everything
> else has terminated and it is alone in the world?
>
>
>
> Ancillary to that question was a question I asked on the RexxLA list,
> which was, if you have a process which ‘runs on’ in this fashion, is
> there some way to detect which method is still ‘active’ (I use the
> word active advisedly, as it is probably in a guarded state).
>
>
>
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