Events Listening, Callback functions

Hello,

I'm wondering if it's possible to bind the excecution of a listener to an condition? for example : assume we have a system of three users :user1,user2,user3.

-user1 and user2 trigger event 'Hello_Request', which user3 is listening to so:

user3 = addlistener([user1,user2],'Hello_Request',@callback1)

-user3 responds with 'Hello_Response', which user1 and user3 are listening to. so:

user1 = addlistener([user3],'Hello_Response',@callback2)
user2 = addlistener([user3],'Hello_Response',@callback2)

Now my question: Is there a way to condition the execution of user1 and user2 that user3 respond s just to the one who send a 'Hello_Request'? I can use different events since my system gets a large number of user which can actually variate.

Thanks in advance for your support!

Bolivar

Answer 1

[Daniel Shub]

You might be able to hack it, but I am not sure that you need to ...

Why not just have callback1 call a hello_response method of the user who triggered the event? If you want to keep it as event based it seems like the Hello_Response event should belong to user1, user1 should listen for this event, and user3 should trigger the event.

I am thinking something like

classdef user < handle
    properties
        name
        helloRequestListener
    end
    events
     Hello_Request
     Hello_Response
    end
    methods
        function obj = user(name)
            obj.name = name;
            obj.helloRequestListener = addlistener(obj, 'Hello_Response', @helloResponse);
        end

          function helloRequest(obj, src, evt)
              disp(['Hello request by ', src.name, ' recieved by ', obj.name]);
              notify(src, 'Hello_Response')
          end

          function helloResponse(src, evt)
              disp(['Hello response by ', src.name]);
          end
      end
  end

called by

user1 = user('user1'); user2 = user('user2'); user3 = user('user3');
addlistener([user1, user2], 'Hello_Request', @user3.helloRequest);
notify(user1, 'Hello_Request');

which returns

Hello request by user1 recieved by user3
Hello response by user1

Note that user2 does not give a response.

[Bolivar]

Hi,

user1 and user2 are independant objects of same type(here is just a sample I'll hvave tousands of it), that is they trigger same events and also listen to the same can be at same time or delayed times. Tell me more on how to hack it and excecute just the corresponding code? or would you propose anything else to solve that matter?

[Daniel Shub]

See my edit ...

Answer 2

[Bolivar]

excellent! that not exactlly what I want but some little modification in the technic will to the way. Thanks a lot!

[Daniel Shub]

It would be helpful to myself, and possibly others, if you could post some simplified code showing what you ultimately do.

[Bolivar]

Hallo Daniel, actually I'm just going to costomize this to my own code nothing really special. notification will be perform as you have demonstrate earlier. Thanks