COMP9321 Web Application Engineering

Transcription

1 COMP9321 Web Application Engineering Semester 2, 2015 Dr. Amin Beheshti Service Oriented Computing Group, CSE, UNSW Australia Week 7 1

2 Design Patterns A pattern is a proven solution to a problem in a context. 2

3 Design Patterns A pattern is a proven solution to a problem in a context. Each pattern expresses a relation between a certain context, a problem, and a solution. 3

4 Design Patterns A pattern is a proven solution to a problem in a context. Each pattern expresses a relation between a certain context, a problem, and a solution. A design pattern represents a solutions to problems that arise when developing a software. 4

5 Design Patterns A pattern is a proven solution to a problem in a context. Each pattern expresses a relation between a certain context, a problem, and a solution. A design pattern represents a solutions to problems that arise when developing a software. Design pattern are granular and applied at different levels such as: Frameworks Subsystems Sub-subsystems 5

6 Design Patterns A pattern is a proven solution to a problem in a context. Each pattern expresses a relation between a certain context, a problem, and a solution. A design pattern represents a solutions to problems that arise when developing a software. Design pattern are granular and applied at different levels such as: Frameworks Subsystems Sub-subsystems Categories include: Design Architectural Analysis Creational Structural Behavioral 6

7 Design Patterns A pattern is a proven solution to a problem in a context. Each pattern expresses a relation between a certain context, a problem, and a solution. A design pattern represents a solutions to problems that arise when developing a software. Design pattern are granular and applied at different levels such as: Frameworks Subsystems Sub-subsystems Categories include: Design Architectural Analysis Creational Structural Behavioral e.g. MVC: Model View Controller 7

8 Design Patterns A pattern is a proven solution to a problem in a context. Each pattern expresses a relation between a certain context, a problem, and a solution. A design pattern represents a solutions to problems that arise when developing a software. Design pattern are granular and applied at different levels such as: Frameworks Subsystems Sub-subsystems Categories include: Design Architectural Analysis Creational Structural Behavioral Gamma et al (Gang of Four) produced a famous book which listed 23 Design patterns 8

9 J2EE Design Patterns 9

10 J2EE Design Patterns 10

11 Web Application Architecture 11

12 Web Application Architecture 12

13 Web Application Architecture 13

14 Web Application Architecture 14

15 Web Application Architecture 15

16 Web Application Layers 16

17 J2EE design guidelines: Web tier 17

18 J2EE design guidelines: Web tier 18

19 Servlet Design Guidelines 19

20 Servlet design guidelines: When to use Servlets 20

21 Servlet design guidelines: When to use Servlets 21

22 JSP Design Guidelines 22

23 JSP Design Guidelines 23

24 JSP Design Guidelines 24

25 JSP Design Guidelines 25

26 JSP Design Guidelines 26

27 JSP Design Guidelines 27

28 JSP Design Guidelines 28

29 JSP Design Guidelines 29

30 General Guideline for Servlet/JSP/JavaBeans 30

31 General Guideline for Servlet/JSP/JavaBeans 31

32 General Guideline for Servlet/JSP/JavaBeans 32

33 Structuring Web applications Architectural Patterns (MVC) 33

34 Structuring Web applications 34

35 Structuring Web applications 35

36 Structuring Web applications 36

37 Model 1 Example 37

38 Model 1 Example 38

39 Model 1 Example 39

40 Model 1 Example 40

41 Model 1 Example 41

42 Model 1 Example 42

43 Model 1 Architecture 43

44 MVC Model View Controller 44

45 Model 2 Architecture = MVC pattern 45

46 Model 2 Architecture = MVC pattern 46

47 MVC Components and Roles MVC can be broken down into three elements: Model - The model represents data and the rules that govern access to and updates of this data. View - The view renders the contents of a model. It specifies exactly how the model data should be presented. Controller - The controller translates the user's interactions with the view into actions that the model will perform. 47

48 MVC Components and Roles 48

49 Model 2 Architecture = MVC pattern 49

50 Model 2 Architecture = MVC pattern 50

51 Model 2 Architecture = MVC pattern 51

52 Model 2 Architecture = MVC pattern 52

53 Case for a centralised controller 53

54 Case for a centralised controller 54

55 Case for multiple controllers 55

56 FrontController Pattern 56

57 FrontController Pattern The Front Controller pattern is a software design pattern. The pattern relates to the design of web applications. It provides a centralized entry point for handling requests. Front controllers are often used in web applications to implement workflows. The front controller may be implemented as a Java object. 57

58 FrontController Pattern The Front Controller pattern is a software design pattern. The pattern relates to the design of web applications. It provides a centralized entry point for handling requests. Front controllers are often used in web applications to implement workflows. The front controller may be implemented as a Java object. 58

59 FrontController implementation: Command Design Pattern 59

60 Command Design Pattern 60

61 Command Design Pattern 61

62 Command Design Pattern 62

63 Command Design Pattern 63

64 Command Design Pattern 64

65 Command Design Pattern 65

66 Command Design Pattern 66

67 Command Design Pattern 67

68 Command Design Pattern 68

69 Command Design Pattern 69

70 Command Design Pattern 70

71 Identifying the Command Pattern in the phonebook lab 71

72 Implementing the Command Pattern 72

73 Typical "Assignment 2" Architecture 73

74 Next Week 74

75 References Core J2EE patterns, Deepak Alur, John Crupi and Dan Marlks, Prentice Hall Patterns of Enterprise Application Architecture, Martin Fowler, Addison-Wesley

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