MATLAB Object-Oriented Programming

Restore Listeners

In this section...

“Create Listener with loadobj” on page 13-36

“Use Transient Property to Load Listener” on page 13-36

“Using the BankAccount and AccountManager Classes” on page 13-38

Create Listener with loadobj

Suppose that you create a property listener and want to be able to save and restore the

event source and the listener. One approach is to create a listener from the loadobj

method.

Use Transient Property to Load Listener

The BankAccount class stores the account balance and an account status. A PostSet

listener attached to the AccountBalance property controls the account status.

When the AccountBalance property value changes, the listener callback determines the

account status. Important points include:

• The BankAccount class defines the AccountManagerListener property to contain
  the listener handle. This property enables the loadobj method to create a listener
  and return a reference to it in the object that is loaded into the workspace.


• The AccountManagerListener property is Transient because there is no need to
  store the listener handle with a BankAccount object. Create a listener that is
  attached to the new BankAccount object created during the load process.


• The AccountBalance listener sets the AccountStatus.


• Only the AccountManager class can access AccountStatus property.

classdef BankAccount < handle

properties (SetObservable, AbortSet)

AccountBalance

end

properties (Transient)

AccountManagerListener

end

properties (Access = ?AccountManager)

13 Saving and Loading Objects