Test 3

Question 1

Briefly describe abstract factory

Answer 1

Provides a way to create an instance of several families of classes.

Question 2

Briefly describe factory method

Answer 2

Provides a way to create an instance of several derived classes.

Question 3

Briefly describe singleton

Answer 3

Provides a way to ensure that only a single instance of a class may exist.

Question 4

Briefly describe composite

Answer 4

This pattern is used when the model of your application can be represented as a tree. It lets you run a behavior recursively over all components of an object tree.

Question 5

Briefly describe facade

Answer 5

Provides a simple interface to a complex subsystem which contains lots of moving parts.

Question 6

Briefly describe proxy

Answer 6

Solves the problem of having an object that consumes a lot of system resources.

Question 7

Briefly describe iterator

Answer 7

Provides a way of accessing the elements of a collection, no matter how the collection is structured.

Question 8

Briefly describe observer

Answer 8

Provides a way to report an object’s state to other objects that are observing it.

Question 9

Briefly describe state

Answer 9

Provides a way to identify all possible states of an object (states), extract all state-specific behaviors into these states, and allow transitions to different states. Essentially, this pattern models a state machine.