AW: [DISCUSS] Where to regster the handler?

[Christofer Dutz]

Hi all,

So, I’ve been fefactoring the Subscription stuff in a branch (not yet pushed 
however).
I stumbled over something:

In the past we had an unsubscription request that took “subscription handles”
This made sense as we had one subscription handle per field.

Now that we’re changing things to have a callback for all fileds in the 
subscription request, I think this method no longer really makes much sense.

I would now rather have someone keep the subscription request and call an 
“unsubscribe” method on this.

So as soon as you’re finished with your subscription a 
“subscriptionResponse.unsubscribe()” call would take care of that.
Or possibly a “subscriptionResponse.getUnsubscriptionRequest().execute()” 
(which might be more in line with our usual patterns.
This way also someone could drop the subscription response and save the 
unsubscriptionRequest till he needs it.

What do you folks think?

Chris


Von: Christofer Dutz <christofer.d...@c-ware.de>
Datum: Montag, 25. März 2024 um 09:32
An: dev@plc4x.apache.org <dev@plc4x.apache.org>
Betreff: AW: [DISCUSS] Where to regster the handler?
Having another look at existing types:

In browse-request we have:


  *   execute()
  *   executeWithInterceptor()

In discovery-request we have:


  *   execute()
  *   executeWithHandler()

So, in order to continue that pattern, what do you think about having two 
options:


  *   execute()
  *   executeWithHandler()

And to add the option to add a handler to the response.

I know this could let users miss first responses, especially as ADS for example 
sends an event directly after subscribing.
However it would be more in line with the rest of the API, which all have an 
“execute” without any arguments.


Thinking even more about everything … I think moving the 
“executeWithInterceptor” .. the interceptor adding should actually more be 
added to the request and not the execution.

Also could we add a “WithHandler” option to every type of request.

Chris



Von: Christofer Dutz <christofer.d...@c-ware.de>
Datum: Montag, 25. März 2024 um 09:15
An: dev@plc4x.apache.org <dev@plc4x.apache.org>
Betreff: [DISCUSS] Where to regster the handler?
Hi all,

so yesterday I‘ve been working on the refactoring of the subscriptions as we 
discussed that on the meetup.
So, we said to register a callback for all fields before the “execute()”


Consumer<PlcSubscriptionEvent> subscriptionConsumer = …;
PlcSubscriptionRequest.Builder builder = 
plcConnection.subscriptionRequestBuilder();
for (int i = 0; i < options.getTagAddress().length; i++) {
    builder.addChangeOfStateTagAddress("value-" + i, 
options.getTagAddress()[i]);
}
PlcSubscriptionRequest subscriptionRequest = 
builder.build(subscriptionConsumer);

// Execute the subscription response.
final PlcSubscriptionResponse subscriptionResponse = 
subscriptionRequest.execute().get();

Right now, I initially thought about adding it to the build()-method, but that 
sort of felt oddly.

Thinking about it a bit more, adding it to the “execute” seemed a bit more like 
what I was looking for.

So, what do you think about doing:


Consumer<PlcSubscriptionEvent> subscriptionConsumer = …;
PlcSubscriptionRequest.Builder builder = 
plcConnection.subscriptionRequestBuilder();
for (int i = 0; i < options.getTagAddress().length; i++) {
    builder.addChangeOfStateTagAddress("value-" + i, 
options.getTagAddress()[i]);
}
PlcSubscriptionRequest subscriptionRequest = builder.build();

// Execute the subscription response.
final PlcSubscriptionResponse subscriptionResponse = 
subscriptionRequest.execute(subscriptionConsumer).get();

What’s your opinion? I prefer the adding to the “execute” method.

Chris