Software LEIC/LETI. Lecture 10

Transcription

1 Software LEIC/LETI Lecture 10

2 Last Lecture Project Management Large Number of Features Project Planning Risk Management Agile Planning Scrum

3 (Sommerville, Fig 3.9)

4 (

5 Executing the Sprint

6 allocating tasks Executing the Sprint

7 allocating tasks daily stand-up meeting Executing the Sprint

8 allocating tasks 15 minutes daily stand-up meeting Executing the Sprint

9 allocating tasks 15 minutes daily stand-up meeting common language Executing the Sprint

10 allocating tasks 15 minutes daily stand-up meeting common language impediments Executing the Sprint

11 allocating tasks 15 minutes daily stand-up meeting common language impediments sticking to the sprint backlog Executing the Sprint

12 allocating tasks 15 minutes daily stand-up meeting common language impediments sticking to the sprint backlog Executing the Sprint white-board for the sprint backlog

13 allocating tasks 15 minutes daily stand-up meeting common language impediments sticking to the sprint backlog Executing the Sprint white-board for the sprint backlog daily estimation of time-remaining

14 allocating tasks 15 minutes daily stand-up meeting common language impediments sticking to the sprint backlog Executing the Sprint white-board for the sprint backlog daily estimation of time-remaining sprint burn-down chart

15 allocating tasks 15 minutes daily stand-up meeting common language impediments sticking to the sprint backlog Executing the Sprint white-board for the sprint backlog daily estimation of time-remaining move stories in/out sprint burn-down chart

16 Today Software Design Design as Structure Data source architectural patterns FénixFramework

17 Software Design

18 There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies - C.A.R. Hoare

19 Design as Structure

20 Module design entity which has an interface

21 a class is a module in object-orientation Module design entity which has an interface

22 a class is a module in object-orientation Module design entity which has an interface what about hotel, activity, bank, car, tax and broker modules?

23 Why is it difficult to change the code?

24 Cost of Change

25 Cost of Change change 100 modules x 1 line of code versus change 1 module x 100 lines of code

26 Propagation of Change changes impact outside the module

27 Propagation of Change changes impact outside the module the interface does not encapsulate the change

28 Locality of Change all changes inside the same module

29 Locality of Change all changes inside the same module the module semantics fits the changes semantics

30 What are the qualities of a good design?

31 Let s look at an example

32 How can we have persistency?

33 store in files How can we have persistency?

34 store in files How can we have store in a relational database persistency?

35 store in files How can we have store in a relational database persistency? store in a nosql database

36 store in files How can we have store in a relational database persistency? store in a nosql database use a programming language that offers persistent structures

37 In our project we use Java and want to store in a relational database

38 Object-relational impedance mismatch graph structure vs tabular structure

39 Bridge the gap Data Source Architectural Patterns

40 Data Source Architectural Patterns Patterns of Enterprise Application Architecture Book

41 Where is the SQL code?

42 Where is the query code?

43 Where is the transactional management code?

44 Where is the domain logic?

45 Where is the correspondence between classes and tables

46 These are design questions! change propagation vs locality of change

47 Data Source Architectural Patterns Table Data Gateway Row Data Gateway Active Record Data Mapper

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49 Table Data Gateway An object that acts as a Gateway to a database table. One instance handles all the rows in the table.

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54 localizes all SQL code for a table in its own class

55 localizes all SQL code for a table in its own class but does not provide an object-oriented interface

56 Row Data Gateway An object that acts as a Gateway to a single record in a data source. There is one instance per row.

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63 localizes all SQL code for a table in its own class

64 localizes all SQL code for a table in its own class provides an object-oriented"/instance interface

65 localizes all SQL code for a table in its own class provides an object-oriented"/instance interface but does not contain the domain logic

66 Active Record An object that wraps a row in a database table or view, encapsulates the database access, and adds domain logic on that data.

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72 SQL code and domain logic are in the same class

73 SQL code and domain logic are in the same class provides an object-oriented /instance interface

74 SQL code and domain logic are in the same class provides an object-oriented /instance interface contains the business logic

75 SQL code and domain logic are in the same class provides an object-oriented /instance interface contains the business logic there is a one to one mapping between the object structure and the database structure

76 SQL code and domain logic are in the same class provides an object-oriented /instance interface contains the business logic there is a one to one mapping between the object how to represent a collection in the database? structure and the database structure

77 Data Mapper A layer of Mappers that moves data between objects and a database while keeping them independent of each other and the mapper itself.

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83 separates SQL code from domain logic

84 separates SQL code from domain logic provides an object-oriented interface

85 separates SQL code from domain logic provides an object-oriented interface contains the business logic

86 separates SQL code from domain logic provides an object-oriented interface contains the business logic allows different mappings between the object structure and the database structure

87 FénixFramewok Java Relational Data Mapper

88 Domain Data Access Layer Data Mapper

89 Hotel Domain Hotel(String code, String name) void checkarguments(string code, String name) Room hasvacancy(room.type type,...)... Hotel_Base Data Access Layer String getcode() void setcode(string code) String getname() void setname(string name) Set<Room> getroomset()...

90 Objects are in a graph FenixFramework.getDomainRoot()

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92 Relations are bidirectional

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94 Hotel hotel = new Hotel( HT12, Paris ); Room room = new Room(hotel, 01, DOUBLE); room.sethotel(hotel) == one to many relationship hotel.addroom(room)

95 DML make it easier

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102 needs to be added to the build path

103 Do we need to create the database tables? DML make it easier

104 src/main/resources/fenix-framework.properties.example

105 src/main/resources/fenix-framework.properties.example it is only necessary to create the database

106 src/main/resources/fenix-framework.properties.example it is only necessary to create the database create database adventures;

107 src/main/resources/fenix-framework.properties.example it is only necessary to create the database what is the create database adventures; database structure?

108 src/main/resources/fenix-framework.properties.example it is only necessary to create the database what is the create database adventures; database structure? It is irrelevant, I love my persistent graph of objects!

109 Transactional annotation

110 write transaction

111 read transaction

112 write followed by read transaction clean the database / write transaction