The Object-Oriented Thought Process, Fourth Edition

Accessors

In most, if not all, examples in this book, the attributes are defined as private so that any other objects cannot access the attributes directly. It would be ridiculous to create an object in isolation that does not interact with other objects—for we want to share appropriate information. Isn’t it necessary to inspect and sometimes change another class’s attribute? The answer is, of course, yes. There are many times when an object needs to access another object’s attributes; however, it does not need to do it directly.

A class should be very protective of its attributes. For example, you do not want object A to have the capability to inspect or change the attributes of object B without object B having control. There are several reasons ...