MATLAB Object-Oriented Programming

For example, suppose that you have a class that changes the name of a property from

OldPropName to NewPropName. You can continue to allow the use of the old name

without exposing it to new users. To support the old property name, define OldPropName

a dependent property with set and get methods:

properties

NewPropName

end

properties (Dependent, Hidden)

OldPropName

end

methods

function obj = set.OldPropName(obj,val)

obj.NewPropName = val;

end

function value = get.OldPropName(obj)

value = obj.NewPropName;

end

end

There is no memory wasted by storing both old and new property values. Code that

accesses OldPropName continues to work as expected. Setting the Hidden attribute of

OldPropName prevents new users from seeing the property.

Assignments made from property set methods cause the execution of any set methods

defined for properties being set. See “Calculate Data on Demand” on page 3-23 for an

example.

Private Set Access with Dependent Properties

If you use a dependent property only to return a value, then do not define a set access

method for the dependent property. Instead, set the SetAccess attribute of the

dependent property to private. For example, consider the following get method for the

MaxValue property:

methods

function mval = get.MaxValue(obj)

mval = max(obj.BigArray(:));

end

end

This example uses the MaxValue property to return a value that it calculates only when

queried. For this application, define the MaxValue property as dependent and private:

8 Properties — Storing Class Data