Exam 2 - L17 - Observer Design Pattern

Question 1

What is the main purpose of the Observer Design pattern?

Answer 1

To allow multiple objects (observers) to automatically respond to changes in another object (subject/publisher), promoting loose coupling.

Question 2

What is loose coupling?

Answer 2

Classes have few dependencies

Question 3

What are the key components in the Observer Pattern?

Answer 3

Subject (Publisher) - Maintains list of observers, provides attach/detach/notify methods.

Observer (Subscriber) - Interface that defines the update() method.

Question 4

What does the subscription mechanism involve?

Answer 4

1. A list to store subscribers
2. Public methods to add/remove subscribers
3. A ‘notifyObservers()’ method to call each observer’s ‘update()’ method

Question 5

What are the advantages of using the Observer Pattern?

Answer 5

Loose coupling

Reusability and modularity

Broadcasting capability to multiple observers

Question 6

What are some potential downsides of the Observer Pattern?

Answer 6

Memory leaks (if observers aren’t detached)

Implementation complexity