2 The Object Model

Lecture



Object-oriented technology is founded on what is called the object model. Its principal elements are: abstraction, encapsulation, modularity, hierarchy, typing, concurrency, and persistence. None of these principles is new in itself, but in the object model they are applied together for the first time.
Object-oriented analysis and design differ fundamentally from the traditional approaches of structured design: here one must conceive of the process of decomposition differently, and the architecture of the resulting software product goes to a considerable degree beyond the notions traditional for structured programming. The differences stem from the fact that structured design is based on structured programming, whereas object-oriented design rests on the methodology of object-oriented programming. Unfortunately, the term "object-oriented programming" means different things to different people. Wegner rightly predicted: "In the 1980s object-oriented programming will occupy the same place that structured programming occupied in the 1970s, but everyone will like it. Every firm will advertise its product as being built with this technology. All programmers will write in this style, and each one differently. All managers will hold forth about it. And no one will know what it actually is" [Wegner, P. [J 1981]] . These predictions continue to come true in the 1990s as well.

In this chapter we shall determine what object-oriented software development is and what it is not, and how this approach to design differs from others, taking into account the seven elements of the object model listed above.

Comments

To leave a comment

If you have any suggestion, idea, thanks or comment, feel free to write. We really value feedback and are glad to hear your opinion.
To reply

Lectures and tutorial on "Object Oriented Analysis and Design"

Terms: Object Oriented Analysis and Design

1.1. The Inherent Complexity of Software
1.2. The Structure of Complex Systems
1.3. Bringing Order to Chaos. The role of decomposition. Algorithmic and object-oriented decomposition.
1.4. On Designing Complex Systems. Engineering as a science and an art
2 The Object Model
2.1. The Evolution of the Object Model
2.2. The Constituent Parts of the Object Approach
2.3. Applying the object model
3 Classes and objects 3.1. The nature of an object
3.2. Relationships among objects
3.3. The Nature of Classes. What Is a Class?
3.4. Relationships among classes (association, inheritance, aggregation, using, instantiation, metaclass)
3.5. The interrelationship of classes and objects.
3.6. The quality of classes and objects
4.1. The importance of proper classification
4.2. Identifying classes and objects
4.3. Key abstractions and mechanisms
5.1. Elements of the notation
5.2. Class diagrams. Classes and their relationships
5.3. State transition diagrams
5.4. Object diagrams
5.5. Interaction diagrams
5.6. Module diagrams
5.7. Process diagrams.
6.1. First principles The process of object-oriented analysis and design
6.2. The micro process of design
6.3. The Macro Process of Design
Management and Planning of an IT Project
7.2. Staffing Allocation of Resources
7.3. Release management
7.4. Reuse. Elements of reuse
7.5. Quality and metrics. Software quality
7.6. Documentation of the Software Product
7.7. Tools for Software Development
7.8. Special Topics Narrowly Specific Problems in Software Development
7.9. Benefits and Risks of Object-Oriented Development
8 Data Acquisition: Weather Monitoring Station 8.1. Analysis
8.2. Designing the weather monitoring station
8.3. Evolution of the application's development
8.4. Maintenance of the software application
9 Framework: a foundation class library 9.1. Analysis
9.2. Design of the application example
9.3. Evolution of the system's design
9.4. Maintenance of the software product
10 Client-Server Architecture: Inventory Tracking 10.1. Analysis
10.2. Design of the Inventory Tracking System
10.3. Evolution and 10.4. Maintenance of the inventory tracking system
11 Artificial intelligence: cryptanalysis
11.2. An example of designing a cryptanalysis system
11.3. Evolution of the development of the cryptanalysis system
11.4. Maintenance of the cryptanalysis system
12 example of the development of a command-and-control system - train traffic management 12.1. Analysis
12.2. An example of designing a train traffic management system
12.3. The evolution of the development of the train traffic management system
12.4. Example: Maintenance of the Train Traffic Management System
Metamodel, metamodelling, metaclass and metaobject