上海充通大学 1.Add Visibility Information SHANGHAI JIAO TONG UNIVERSITY UML defines three levels of visibility: Private (Class implementor): A private attribute can be accessed only by the class in which it is defined. A private operation can be invoked only by the class in which it is defined. Private attributes and operations cannot be accessed by subclasses or other classes. Protected (Class extender): A protected attribute or operation can be accessed by the class in which it is defined and on any descendent of the class. Public (Class user): A public attribute or operation can be accessed by any class. Software EngineeringSoftware Engineering 1. Add Visibility Information UML defines three levels of visibility: Private (Class implementor): • A private attribute can be accessed only by the class in which it is defined. • A private operation can be invoked only by the class in which it is defined. • Private attributes and operations cannot be accessed by subclasses or other classes. Protected (Class extender): • A protected attribute or operation can be accessed by the class in which it is defined and on any descendent of the class. Public (Class user): • A public attribute or operation can be accessed by any class