To ensure that all listeners in class B are executed before any other function of B is called, you can use a few strategies to manage the flow of your program. Here’s a structured approach:
tep-by-Step Solution
- Set Up Class A: Class A should have an event that it notifies whenever data changes.
- Set Up Class B: Class B should have listeners that respond to the event from class A. You will need to ensure that these listeners are executed before other methods in class B.
- Use a Flag or State Variable: In class B, use a flag or state variable to track whether the listeners have been executed. This can help control when other methods are allowed to run.
Example Implementation:
Class A
classdef A < handle
events
DataChanged
end
methods
function notifyChange(obj)
notify(obj, 'DataChanged');
end
end
end
Class B
classdef B < handle
properties (Access = private)
listeners
listenersExecuted = false
end
methods
function obj = B(source)
% Add a listener to the DataChanged event of class A
obj.listeners = addlistener(source, 'DataChanged', @(src, event)obj.handleDataChange(src, event));
end
function handleDataChange(obj, ~, ~)
% Perform actions when data changes
disp('Data changed!');
% Set the flag to true after handling
obj.listenersExecuted = true;
end
function someMethod(obj)
% Check if listeners have been executed before proceeding
if ~obj.listenersExecuted
error('Listeners have not been executed yet.');
end
% Proceed with the method's operations
disp('Executing someMethod...');
end
end
end
Usage Example
% Create an instance of class A
a = A();
% Create an instance of class B with a as the source
b = B(a);
% Notify change in class A
a.notifyChange();
% Call someMethod in class B (this will only succeed if listeners have executed)
b.someMethod();
