The Unified Modeling Language User Guide SECOND EDITION [Electronic resources] نسخه متنی

Chapter 4. Classes

In this chapter

• Classes, attributes, operations, and responsibilities

• Modeling the vocabulary of a system

• Modeling the distribution of responsibilities in a system

• Modeling nonsoftware things

• Modeling primitive types

• Making quality abstractions

Classes are the most important building block of any object-oriented system. A class is a description of a set of objects that share the same attributes, operations, relationships, and semantics. A class implements one or more interfaces.

You use classes to capture the vocabulary of the system you are developing. These classes may include abstractions that are part of the problem domain, as well as classes that make up an implementation. You can use classes to represent software things, hardware things, and even things that are purely conceptual.

Well-structured classes have crisp boundaries and form a part of a balanced distribution of responsibilities across the system.