Lesson 6

Question 1

“Design is not just how it
looks and feels like.
Design is how it works”

Answer 1

Steve Jobs

Question 2

Design is the ______ of an experience.

Answer 2

creation

Question 3

It’s also the _______ of the said creation and how well it’s
organized.

Answer 3

process

Question 4

On top of that, design is the _____, i.e. the things we see,
hear, and feel.

Answer 4

result

Question 5

There is no definite meaning for design, but to summarize
it, Design is a ______________ in such a way as
best to ___________________

Answer 5

plan for arranging elements, accomplish a particular purpose

Question 6

are typical solutions to
commonly occurring problems in software
design.

Answer 6

Design patterns

Question 7

They are like _____________ that you
can customize to solve a recurring design
problem in your code.

Answer 7

pre-made blueprints

Question 8

The pattern is not a specific piece of code,
but a __________ for solving a
particular problem.

Answer 8

general concept

Question 9

_________ is a cooking recipe, where each
step is required to achieve a goal.

Answer 9

Algorithm

Question 10

always defines a clear
set of actions that can achieve some goal,

Answer 10

Algorithm

Question 11

is a more high-level description of a
solution.

Answer 11

pattern

Question 12

Design pattern is a _______, where the
results are visible, but the implementation is
up to you.

Answer 12

blueprint

Question 13

of the pattern briefly describes both the problem and
the solution.

Answer 13

Intent

Question 14

further explains the problem and the solution the
pattern makes possible.

Answer 14

Motivation

Question 15

of classes shows each part of the pattern and how
they are related.

Answer 15

Structure

Question 16

in one of the popular programming languages
makes it easier to grasp the idea behind the pattern.

Answer 16

Code example

Question 17

The most universal and high-level patterns are
_______________. Developers can
implement these patterns in virtually any
language.

Answer 17

architectural patterns

Question 17

The most basic and low-level patterns are
often called ______. They usually apply only to
a single programming language.

Answer 17

idioms

Question 18

provide object creation mechanisms that
increase flexibility and reuse of existing code.

Answer 18

Creational patterns

Question 19

explain how to assemble objects and classes into
larger structures, while keeping the structures flexible and efficient.

Answer 19

Structural patterns

Question 20

take care of effective communication and the
assignment of responsibilities between objects

Answer 20

Behavioral patterns

Question 21

aren’t obscure, sophisticated concepts—quite
the opposite.

Answer 21

Design patterns

Question 22

are typical solutions to common problems in object-
oriented design.

Answer 22

Patterns

Question 23

The concept of patterns was first described by

Answer 23

Christopher Alexander in A Pattern Language:
Towns, Buildings, Construction.

Question 24

The book describes a ________________. The units of this language are patterns.

Answer 24

“language” for designing the urban environment

Question 25

The idea was picked up by four authors:

Answer 25

Erich Gamma, John Vlissides, Ralph Johnson, and Richard Helm

Question 26

In 1995, they published _______________________, in which they applied the concept of design patterns to programming.

Answer 26

Design Patterns: Elements of Reusable Object-Oriented Software

Question 27

Due to its lengthy name, people started to call it ________________ which was soon shortened to simply __________.

Answer 27

“the book by the gang of four” “the GOF book”.

Question 28

Design patterns are a toolkit of _____________ solutions to common problems in software design.

Answer 28

tried and tested

Question 29

SOLID is a mnemonic for _____________ intended to make software designs more understandable, flexible and maintainable.

Answer 29

five design principles

Question 30

___________ introduced them in the book Agile Software Development, Principles, Patterns, and Practices

Answer 30

Robert Martin

Question 31

Using these principles mindlessly __________________. The cost of applying these principles into a program’s architecture

Answer 31

can cause more harm than good.

Question 32

A class should have just one reason to change. Try to make every class responsible for a single part of the functionality provided by the software, and make that responsibility entirely encapsulated by (or hidden within) the class. The main goal of this principle is reducing complexity The real problems emerge when your program constantly grows and changes. At some point classes become so big that you can no longer remember their details.

Answer 32

Single Responsibility Principle

Question 33

Classes should be open for extension but closed for modification. The main idea of this principle is to keep existing code from breaking when implementing new features. A class is open if you can extend it, produce a subclass and do whatever you want with it—add new methods or fields, override base behavior, etc. A class is closed (or complete) if it’s 100% ready to be used by other classes—its interface is clearly defined and won’t be changed in the future.

Answer 33

Open/Closed Principle

Question 34

When extending a class, remember that you should be able to pass objects of the subclass in place of objects of the parent class without breaking the client code. This principle is named by Barbara Liskov, who defined it in 1987 in her work Data abstraction and hierarchy

Answer 34

Liskov Substitution Principle

Question 35

Clients shouldn’t be forced to depend on methods they do not use. Try to make your interfaces narrow enough that client classes don’t have to implement behaviors they don’t need.

Answer 35

Interface Segregation Principle

Question 36

● High-level classes shouldn’t depend on low-level classes. Both should depend on abstractions. ● Abstractions shouldn’t depend on details. Details should depend on abstractions.

Answer 36

Dependency Inversion Principle

Question 37

implement basic operations such as working with a disk, transferring data over a network, connecting to a database, etc.

Answer 37

Low-level classes

Question 38

contain complex business logic that directs low-level classes to do something.

Answer 38

High-level classes