CIS 112

1. CIS 112 Exam Review

2. Exam Content • 100 questions valued at 1 point each • 100 points total • 10 each from Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 • Exam is open-book, open-notes, internet access

3. What We Covered • Chapter 1 • history of the object-oriented approach • Chapter 2 • introduction to the object-oriented approach • Chapter 3 • a way of thinking about objects • Chapter 4 • introduction to terms and concepts • Chapter 5 • UML notation for model building

4. What We Covered • Chapter 6 • requirements modeling • Chapter 7 • hierarchies and requirements models • Chapter 8 • object-oriented system development life cycles • Chapter 9 • detailed case study • Chapter 10 • Object-oriented Design

5. Object-oriented system development • building block approach to system development • identify the objects that are needed in the system • identify objects that already exist and can be reused

6. Benefits of the object-oriented approach • addresses three pervasive problems with traditional system development • quality, productivity, and flexibility • each object is small thereby reducing complexity and leading to higher quality • an object can be reused once it is written, implemented, and tested • system can be easily modified by changing only the appropriate objects

7. Hierarchies • organization of classes into super and sub classes • sub classes inherit attributes and methods from those above in the hierarch • allows system to be broken down into smaller pieces that are easier to understand, implement, maintain • ensures independence of system components

8. Whole / Part Components Aggregation Whole Part Super Class Sub Class

9. Generalization / Specialization Generalization Specialization Super Class Sub Class Source: http://people.cs.vt.edu/~kafura/cs2704/oop.swe.html

10. Abstractions • refers to the relevant features and behaviors of an object • abstract classes are not used to create objects • designed to act as a base class to be inherited by other classes • design concept in program development that provides a foundation upon which other classes are built

11. CRC • class, responsibility, collaboration • used to identify and explore the nature of a system • CRC card is an index card used to represent the responsibilities of classes and the interaction between the classes • informal approach to object oriented modeling • created through scenarios, based on the system requirements, that model the behavior of the system • aids in capturing essence of object-oriented systems

12. Unified Modeling Language • standardized approach to object-oriented terminology and diagramming notation • used to define object-oriented constructs and models

13. Classes differ from objects • A class is a type of thing or a general category. • An object is a specific instance of a class.

14. Inheritance • Inheritance means get something from. • One class of objects can inherit attributes and methods from another. • This type of relationship is shown in the generalization/specialization hierarchy.

15. Polymorphism • literally means "multiple forms“ • extremely important to object-oriented programmers who have to implement messages • ability to send the same message to different receivers and have the message trigger the right method within each receiver

16. Sequence diagrams • presents object interaction arranged in time sequence • shows the objects involved in the scenario and the sequence of messages that are exchanged • show interactions among objects and with outside actors for a specific scenario or instance of a use case

17. Actors • either a person (user) interacting with the system or another system interacting with the system • use cases capture the main functionality of a system from the perspective of a user or actor

18. Use cases • identified by looking for events that might cause the user to interact with the system • a use case might have more than one scenario

19. Verifying requirements satisfaction • walk through all use cases

20. Custom methods • necessary when the class must process messages not handled by standard methods

21. Inheritance • Inheritance means get something from. • One class of objects can inherit attributes and methods from another. • This type of relationship is shown in the generalization/specialization hierarchy.

22. Generalization / Specialization Generalization Specialization Heirs Super Class Inherits From Sub Class Source: http://people.cs.vt.edu/~kafura/cs2704/oop.swe.html

23. Abstract Classes • Exists only to allow subclasses to inherit from it. • Objects of that class type not normally created. • matter of design / implementation policy • nothing to prevent it actually being done

24. Development Life Cycle • Widely used framework for organizing and managing system development process. • Five phases • planning • analysis • design • implementation • maintenance

25. Process vs. Technique • “Process” explains what tasks to do and when to do them. • “Technique” describes approaches that could or should be used for the tasks at hand. • how to implement the process

26. Objectives vs. Scope • Objectives are statements that define the expected benefits of the system. • Scope defines the boundary of the system. • describes what the system will be used for • defines main users • prevents requirements creep • ever-expanding objectives • keeps cost and schedule under control

27. Starting an Object-Oriented Project • Start by identifying the most important business events. • there might be many more events buy only the important or typical events need to be identified early on • this can lead rapidly to an initial prototype that can ultimately be expanded into the full system • yields gradual implementation and growing benefits

28. Use Cases • Use cases provide natural way of dividing the system into manageable units. • The objective of use cases is to identify what the system must do for the user to complete required work tasks.

29. Physical vs. Logical Models • Physical model includes details of system implementation. • Logical model specifies what is required without defining implementation details.

30. User Evaluation • A variety of different types of users will typically interact with a system. • Prototyping and evaluation by users will help identify the most effective design of the overall system structure and user interface.

31. Considerations During Transition • Three main areas need to be considered during transition to object-oriented methods. • tools • methodology or means of employment • organization’s culture

32. Benefits of OO Implementation • Methods and attributes can be added to existing object classes without disrupting the rest of the system. • New classes can be added easily. • Additional features can be added after the main functionality has been implemented.