Lecture 10

Question 1

What are three types of reuse?

Answer 1

• Libraries
• Toolkits frameworks
• Components

Question 2

Reuse, what is a library?

Answer 2

-reusable, importable code, typically single purpose

E.g.: OpenGL, OpenCV

Functionality accessed through the API.

Question 3

Reuse, what is a framework?

Answer 3

A framework is a set of cooperating classes that make up a reusable design for a specific class of software

Frameworks permit realization or specialization primarily by subclassing at “well-articulated extension points

Question 4

Reuse, what is a component?

Answer 4

multiple use, non-context-specific, composable, encapsulated, independently deployed and versioned (Szyperski and Messerschmitt, 2002)

Vaadin widgets are an example of components

Question 5

What is a collection?

Answer 5

a group of objects

Question 6

What is a list?

Answer 6

A collection that is ordered by a numerical

index. Duplicate elements are possible.

Question 7

What is a set?

Answer 7

A collection that permits no duplicates. A set may or may not be ordered.

Question 8

What is a map?

Answer 8

A collection that links keys to corresponding values. Keys may or may not be ordered.

Question 9

What is the iterator pattern?

Answer 9

Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation.

Question 10

What is the adaptor pattern?

Answer 10

Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn’t otherwise because of incompatible interfaces.

American plug, adapter, European socket

(NASA/SpaceX adapter example)

Question 11

What is the proxy pattern?

Answer 11

Provide a surrogate or placeholder for another object to control access to it.

Question 12

What is the decorator pattern?

Answer 12

Attach additional responsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extended functionality.