OO Sequence Diagrams (PPT 16-17) Flashcards Preview

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Flashcards in OO Sequence Diagrams (PPT 16-17) Deck (9)
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1
Q

What does a sequence diagram do?

A

Models the time dependent behaviour of the objects in a system

2
Q

What do we need to do for each use case to use it in a sequence diagram?

A
  • Identify actors and objects involved
  • Add timelines for them
  • Analyse use case sequence of events
  • Identify messages/stimuli between objects required to address the use case dialogue
3
Q

What does a sequence diagram allow us to do?

A
  • Start making choices about how the system will be implemented
  • Verify our static design is correct
  • Verify the relationships identified
  • Identify class methods/functions
4
Q

What is coupling?

A

A measure of how strongly one class is connected to or relies on other classes in the system

5
Q

What is cohesion?

A

A measure of how strongly related and focused the responsibilities of a class are

6
Q

What are some problems that can occur and are fixed by coupling and cohesion?

A
  • Changes in unrelated classes have knock on effect
  • Harder to reuse in isolation
  • Harder to maintain

Solution is minimise coupling but maximise cohesion

7
Q

What is a design pattern?

A

Descriptions of common, re-occuring problems during the design of software systems and well known solutions

8
Q

Why are design patterns important?

A

They address many issues related to maintainability and re-usability of a software system

9
Q

What do design patterns involve?

A
  • Inventing new class

- Re-arranging existing classes to support design