CNIT 182 Chapter 6 Tilley Textbook

What is object-oriented (O-O) analysis?

A method of describing an information system by identifying objects that represent real-world entities like people, places, events, or transactions.

What is the end product of object-oriented analysis?

An object model that represents the system in terms of objects and O-O concepts.

Why is O-O analysis popular?

It integrates easily with O-O programming languages, produces modular and reusable designs, and simplifies maintenance.

What is an object?

A person, place, event, or transaction that is significant to the information system.

What does an object contain?

Attributes (data that describe it) and methods (actions it can perform).

What is an instance of an object?

A specific example of a class (e.g., a specific student is an instance of the “Student” class).

What does the “state” of an object mean?

It describes the current status of the object (e.g., a student can be “enrolled,” “graduated,” or “withdrawn”).

What are attributes?

Characteristics that describe an obejct (like adjectives describing nouns).

Who defines object attributes?

Systems analysts during the system development process.

Can attributes be inherited?

Yes, objects can inherit attributes from parent classes.

What are methods?

Tasks or functions an object performs when it receives a message.

How are methods similar to verbs?

They describe actions an object can perform (ex: calculateTotal, updateRecord)

Give an example of a method.

A “Student” object might perform the method “registerForCourse()”.

What is a message in object modeling?

A command telling an object to perform a specific method.

What is polymorphism?

When the same message gives different meanings or results depending on the object that receives it.

Example of polymorphism

The message “play” might cause a “MusicPlayer” object to play a song and a “dog” object to perform a trick.

What is encapsulation?

Combining data (attributes) and actions (methods) into one self-contained unit (the object).

Why is encapsulation important?

It hides internal workings, protects data, and allows modular system design.

What real-world concept is encapsulation similar to?

A “black box” — you can use it without knowing its internal details.

What is a class?

A category or blueprint for objects with shared attributes and methods.

What is an instance?

A specific object within a class (e.g., “John Doe” is an instance of the “Student” class).

What is a subclass?

A more specific category within a class that inherits its traits but can add new ones.

What is a superclass?

A more general class that provides common attributes to its subclasses.

What is inheritance?

The strongest relationship between objects; a child object derives attributes or methods from a parent.

Why is inheritance useful?

It promotes code reuse and consistent structure across related classes.

What are relationships among objects?

Connections that define how objects interact or share information.

What is UML (Unified Modeling Language)?

a standardized way to visually represent system components and their relationships.

What does UML use to represent system elements?

A set of symbols for actors, use cases, activities, and object relationships.

What is a use case?

A specific function or process initiated by an actor that achieves a goal in the system.

What does an actor represent in a use case diagram?

A user or external system that interacts with the system.

What is an activity diagram?

A visual showing the sequence of actions and decision points in a process.

What is a class diagram?

A diagram that shows object classes and their relationships (attributes, methods, and associations).

Give an example of inheritance in a university system.

The “GraduateStudent” class might inherit attributes like “name” and “studentID” from the “Student” superclass but add “thesisTitle.”

In UML, what shape represents a use case?

An oval.

In UML, what shape represents an actor?

A stick figure.

What is a use case?

A specific function or process initiated by an actor that achieves a goal in the system.