Component-Level Programming

9780130458049

013045804X

This book is based on a course in component-level design that I taught at the University of South Florida in the fall of 2000--a course that was taught as a follow-on to a course in object-oriented design. (It is helpful for students to have some knowledge of object-oriented design before studying this material, but it is not essential.) The course was aimed at advanced undergraduates but would also be acceptable as an introductory course at the graduate level. For a long time, it had been clear that it was necessary to offer courses in component-level design. Component-based languages such as Visual Basic have become widely used as development engines in the commercial world, and computer science students have needed a thorough grounding in such languages. However, a course in Visual Basic, or some other component-based development language, tells only half the story. Such a course will show students how to use preexisting components, but it will not show them how to create their own components. When developing new component-based applications, it is necessary to combine components with code written in the host language (Visual Basic and others). There is a natural division between the functionality that should be implemented as part of a component and the functionality that should be programmed in the host language. While it is generally preferable to purchase third-party components rather than develop one's own components, there are many applications for which components do not yet exist. For custom software, this tends to be the rule rather than the exception, and there is no reason to suppose that this will change in the future. Students will discover here the other side of component-based development--namely, the development of the components themselves. This book will show them not only how to develop a wide variety of different components but also how to divide up an application into components and host-level coding. Chapters 1 through 5 contain the basic material that should be included in every course. The presentation of this material should precede the study of later chapters. Chapters 6 through 18 are relatively independent of one another and can be presented in any order. However, Chapter 7 does serve as the basis for a number of other chapters--in particular, Chapters 8, 9, and 11, and parts of Chapters 10 and 12. I would recommend including the material covered in Chapters 6, 7, and 13 in every course. (Because Chapter 6 presents material that can be used for a substantial number of enjoyable student projects, I prefer to present this material first to enable students to get started with longer projects.) Chapters 19 and 20 contain material for students who plan to do further study in component-level design. Chapter 13 provides a bridge between component-level software and more typical types of programming. Software that has been developed for a character-based interface such as MS-DOS or the UNIX shell can be converted to component-level software by using the techniques of this chapter. Selection of the other chapters is a matter of taste. I try to include as much of this material as possible. Chapter 19 can be presented any time after the presentation of Chapter 7. These chapters are actually independent of one another, but the material of Chapter 19 is difficult to motivate without some examples. Chapter 7 and Chapter 13 provide such examples. The flowchart shown here should help in designing a course around this material. Students will find this course appealing because it enables them to develop the same types of software that they have used on their own computers. Furthermore, it enables them to develop a wide variety of sophisticated-looking software without having to learn all of the details of GUI programming. As courses in component-based development systems become more widely available, the material of this book should become corres