MATLAB Object-Oriented Programming

The Utility class is handle compatible. Therefore, you can use it in the derivation of

classes that are either handle classes or value classes. See “Class Introspection and

Metadata” for information on using meta-data classes.

Return Modified Objects

The resetDefaults method defined by the Utility class returns the object it modifies.

When you call resetDefaults with a value object, the method must return the modified

object. It is important to implement methods that work with both handle and value

objects in a handle compatible superclass. See “Object Modification” on page 5-63 for

more information on modifying handle and value objects.

Consider the behavior of a value class that subclasses the Utility class. The

PropertyDefaults class defines three properties, all of which have default values:

classdef PropertyDefaults < Utility

properties

p1 = datestr(rem(now,1)) % Current time

p2 = 'red' % Character vector

p3 = pi/2 % Result of division operation

end

end

Create a PropertyDefaults object. MATLAB evaluates the expressions assigned as

default property values when the class is first loaded. MATLAB uses these same default

values whenever you create an instance of this class in the current MATLAB session.

pd = PropertyDefaults

pd =

PropertyDefaults with properties:

p1: ' 4:42 PM'

p2: 'red'

p3: 1.5708

Assign new values that are different from the default values:

pd.p1 = datestr(rem(now,1));

pd.p2 = 'green';

pd.p3 = pi/4;

All pd object property values now contain values that are different from the default values

originally defined by the class:

12 How to Build on Other Classes