Events Listening, Callback functions

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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

Accepted Answer

Daniel Shub
Daniel Shub on 24 Jul 2013
Edited: Daniel Shub on 25 Jul 2013
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.
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More Answers (1)

Bolivar
Bolivar on 25 Jul 2013
excellent! that not exactlly what I want but some little modification in the technic will to the way. Thanks a lot!
  2 Comments
Bolivar
Bolivar on 29 Jul 2013
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

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