Design Pattern and Principles

Question 1

Who said this?
“Design is not just how it
looks and feels like.
Design is how it works”

Answer 1

Steve Jobs

Question 2

is the creation of experience

Answer 2

Design

Question 3

Design is the ______ of the said creation and how well it’s organized

Answer 3

process

Question 4

Design is the _____ i.e. the things we see hear, and feel

Answer 4

result

Question 5

There is a definite meaning for design(T or F)

Answer 5

F (there is no)

Question 6

Design is a plan for arranging _____ in such a way as best to accomplish a particular purpose.

Answer 6

elements

Question 7

are typical solutions to commonly occurring problems in software design

Answer 7

Design petterns

Question 8

Design patterns are like ____ _____that you can customize to solve a recurring design problem in your code

Answer 8

pre-made blueprint

Question 9

Design Pattern is a specific piece of code, not a general concept for solving particular problems(T or F)

Answer 9

F (is not specific piece of code but a general concept)

Question 10

Design Pattern and Algorithm are interchangeble(T or F)

Answer 10

F( Algo = cooking recipe; DP = Blueprint)
(Algo= define set of actions; DP= high-level desc of solution)

Question 11

Sections that are usually present in patterm descriptions

Answer 11

Intent
Motivation
Structure
Code Exampe

Question 12

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

Answer 12

Intent

Question 13

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

Answer 13

Motivation

Question 14

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

Answer 14

Structure

Question 15

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

Answer 15

Code example

Question 16

The most basic and low-level patterns are often called _____

Answer 16

idioms

Question 17

The most universal and high-level pattern are _____ ______. Devs can implement these patterns virtually in any language.

Answer 17

Architectural patterns

Question 18

All patterns can be categorized by their ______ or ______

Answer 18

intent or purpose

Question 19

3 main groups of pattern

Answer 19

Creational Pattern
Structural Pattern
Behavioral Pattern

Question 20

provide object creation mechanisms that increase flexbility and reuse of existing code

Answer 20

Creational pattern

Question 21

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

Answer 21

Structural pattern

Question 22

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

Answer 22

Behavioral patterns

Question 23

are typical solutions to common problems in object oriented design

Answer 23

Patterns

Question 24

Who first described the concept of pattern

Answer 24

Christopher Alexander in his book A pattern Language

Question 25

This book describes a language for designing the urban environment, the units this language are pattern

Answer 25

A Pattern Language: Towns, Building, Construction

Question 26

The four authors who picked up the Idea of patterns (EG, JV, RJ, RH)

Answer 26

Erich Gamma John Vlissides Ralph Johnson Richard Helm

Question 27

Erich Gamma John Vlissides Ralph Johnson Richard Helm published a back, what is that book?

Answer 27

Design Pattern: Elements of Reusable Object-Oriented Software( The book by the gang of four)/ (the GOF book)

Question 28

Design patterns are a toolkit of ______and ______solutions to common problems in software design

Answer 28

Tried and Tested

Question 29

several universal principles of software design(3+2)

Answer 29

1. Encapsulate What Varies 1.1 Encapsulate on a method level 1.2 Encapsulate on a class level 2. Program to an interface not an implementation 3. Favor composition Over Inheritance

Question 30

Identify the aspects of you application that vary and separate them from what stays the same; the main goal of this principle is to MINIMIS THE EFFECT CAUSE BY CHANGES. With this, you spend less time getting the program “afloat”, more time for you to implement features.

Answer 30

Encapsulate What Varies

Question 31

in the principle, Encapsulate What Varies, you can isolate the part of the program that vary in ______ modules

Answer 31

independent modules

Question 32

Anticipate parts of you code that might need to change in the future. if you knew that a part of your code may change during the program's lifetime, you have to put it in a separate method. This is to make sure that if ever that part of a code changes, it is now easier to isolate the problem without ruining the entire code.

Answer 32

Encapsulate on a method level

Question 33

Overtime you might want to add more responsibilities to a method which used to do a simple thing. Adding another method to help the first method may help, but this may blur the primary responsibility of the containing class itself. Extracting the method to another class might make things much more clear and simple.

Answer 33

Encapsulate on a class level

Question 34

Depend on abstraction, bot concrete classes. Make sure that you design is flexible: the code can be extended without breaking existing code. This can allow classes to collaborate, adding further functionality and flexibility to you code. This through abstract classes and polymorphism

Answer 34

Program to an interface, not an implementation

Question 35

Caveats of inheritance:

Answer 35

A subclass can't reduce the interface of the superclass When overriding method you need to make sure that the new behavior is compatible with the base one. Inheritance breaks encapsulation of the superclass Subclasses are tightly coupled to superclass Trying to reuse code through inheritance can lead to creating parallel inheritance hierarchies.

Question 36

an alternative to inheritance is ______

Answer 36

composition

Question 37

if inheritance represents the "IS-A" relationship, composition represents the "_______ relationship.

Answer 37

HAS-A relationship

Question 38

You may also use a more relaxed variant of composition, which is called_______

Answer 38

Aggregation

Question 39

Is a mnemonic for five design principles intended to make software design more understandable, flexible and maintainable.

Answer 39

SOLID

Question 40

Who introduced the 5 SOLID Principles, and what book was it in?

Answer 40

Robert Martin in his book Agile Software Development, Principles, Patterns, and Practices

Question 41

SOLID stands for what?

Answer 41

Single Responsibility Principles Open/Closed Principle Liskov Substitution Principle Interface Segregation Principle Dependency Inversion Principle

Question 42

A class should have just one reason to change. Every class = single part func. + make encapsulated(hidden) by class

Answer 42

Single Responsibility Principles

Question 43

What is the main goal of SRP?

Answer 43

Reducing Complexity

Question 44

The main problem with SRP that when the program constantly grow and change. At some point classes become so ____ that you can no longer remember their details

Answer 44

big

Question 45

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 features

Answer 45

Open/Closed Principle

Question 46

a class is ____ if you can extend it, produce a subclass and whatever you want with it-- add new methods or fields, overrides base behavior, etc.

Answer 46

Open

Question 47

A class is ____ or _____ 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 47

closed

Question 48

In OCP, instead of changing the code of the class directly, you can create a ______ and override parts of the original class that you want to behave differently.

Answer 48

Subclass

Question 49

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

Answer 49

Liskov Substitution Principle

Question 50

Who named LSP in 1987

Answer 50

Barbara Liskov

Question 51

Which work Barbara Liskov in 1987 did she defined LSP?

Answer 51

Data abstraction and hierarchy

Question 52

In LSP, when overriding a method, _____the base behavior rather than replacing it with something else entirely

Answer 52

extend

Question 53

LSP is critical when developing _____ and ____ because your classes are going to be used by other people whose code you can't directly access and change.

Answer 53

Libraries and framework

Question 54

LSP has a set of formal requirements for subclasses and specifically for their methods

Answer 54

1. Parameter types in a method of a subclass should match or be more abstract than parameter types in the method of the superclass 2. The return type in a method of a subclass should match or be a subtype of the return type in the method of the superclass. 3. A method in a subclass shouldn't throw types of exceptions which the base method isn't expected to throw 4. A subclass shoudn't strengthen pre-conditions 5. shoudlnt weaken post conditions as well 6. Invariant of a superclass must be preserved 7. A subclass shouln't change values of private fields of the superclass

Question 55

Clients shouldn't be forced to depend on method they do not use. Make interface narrow enough "fat" interface = not want dont cram unrelated methods Break into several more refined interface

Answer 55

Interface Segregation Principle

Question 56

High-level classes shouldn't depend on low-level classes. Both should depend on abstractions.

Answer 56

Dependency Inversion Principle

Question 57

Abstraction should dependent on details(T or F)

Answer 57

F should not depend on details

Question 58

Implement BASIC OPERATIONS such as working with a disk, transferring data over a network, connecting to a database, etc.

Answer 58

Low-level classes

Question 59

contain COMPLEX BUSINESS LOGIC that directs low-level classes to do something

Answer 59

High-level classes