MATLAB Programming

9 Classes and Objects
not support passing arguments by reference (i.e., pointers). Functions can
change only their private, temporary copy of an object. Therefore, to change
an existing object, you must create a new one, and then replace the old one.
The following sections provide more detail about implementation techniques
for the set, get, subsasgn, andsubsref methods.
The set and get Methods
The set and get methods provide a convenient way to access object data in
certain cases. For example, suppose you have created a class that defines
an arrow object that MATLAB can display on graphs (perhaps composed of
existing MATLAB line and patch objects).
To produce a consistent interface, you could define set and get methods that
operateonarrowobjectsthewaytheMATLABset and get functions operate
on built-in graphics objects. The set and get verbs convey what operations
they perform, but insulate the user from the internals of the object.
Examples of set and get Methods
See the following sections for examples of set and get methods:
• “The Asset get Method” on page 9-44 and“TheAssetsetMethod”onpage
9-45
• “The Stock get Method” on page 9-52 and “The Stock set Method” on page
9-53
Property Name Methods
As an alternative to a general set method, you can write a method to handle
the assignment of an individual property. The method should have the same
name as the property name.
For example, if you defined a class that creates objects representing employee
data, you might have a field in an employee object called salary. Youcould
then define a method called salary.m that takes an employee object and a
value as input arguments and returns the object with the specified value set.
9-14