MATLAB Object-Oriented Programming

The following diagram illustrates the event model.

Listener1

Properties

EventName = ‘InsufficientFunds’

FunctionHandle = @Callback1

Listener2

Properties

EventName = ‘InsufficientFunds’

FunctionHandle = @Callback2

2. The notify method
   triggers an event, and a
   message is broadcast.


3. Listeners awaiting message
   execute their callbacks.

(The broadcasting object
does not necessarily know
who is listening.)

1. The withdraw method is called.
   BankAccount

Properties

AccountNumber

AccountBalance

Methods

Events

InsufficientFunds

InsufficientFunds

InsufficientFunds

if AccountBalance <= 0

notify(obj,’InsufficientFunds’);

end

deposit

withdraw

Limitations

There are certain limitations to the use of events:

• The event source cannot guarantee that listeners exist when triggering the event.


• A listener cannot prevent other listeners from being notified that the event occurred.

Event and Listener Concepts