Hendrik Lösch - Lose gekoppelt wie nie, DI vs. IOC - DevDay 2016

Transcript

3. 1. It is hard to change because every change affects too many other parts of the system. (Rigidity - Starr) 2. When you make a change, unexpected parts of the system break. (Fragility - Zerbrechlich) 3. It is hard to reuse in another application because it cannot be disentangled from the current application. (Immobility - Unbeweglich) Quelle: http://www.objectmentor.com/resources/articles/dip.pdf
4. A B X
5. • Basistechnologien (.Net, Java, Ruby, …) • Basisdatentypen (int, string, char…) • Datenhaltungsklassen und Transferobjekte • Domänen spezifische Algorithmen und Datenbanken • UI Logik • … beständig unbeständig
6. User Interface Business Layer Data Access Layer Cross Cutting Concerns
7. User Interface Business Layer Data Access Layer Cross Cutting Concerns
8. A B X b ?
9. public class A { IB b; public A(IB b) { this.b = b; } }
10. User Interface Business Layer Data Access Layer Cross Cutting Concerns
11. Robert C. Martin (Uncle Bob) The SOLID principles are not rules. They are not laws. They are not perfect truths. They are statements on the order of “An apple a day keeps the doctor away.” This is a good principle, it is good advice, but it’s not a pure truth, nor is it a rule. “ ” Quelle: https://sites.google.com/site/unclebobconsultingllc/getting-a-solid-start
12. ingle Responsibility Principle pen Closed Principle iskov Substitution Principle nterface Segregation Principle ependency Inversion Principle S O L I D
13. ingle Responsibility Principle pen Closed Principle iskov Substitution Principle nterface Segregation Principle ependency Inversion Principle S O L I D Eine Klasse sollte nur eine Verantwortlichkeit haben. Quelle: http://www.clean-code-developer.de/
14. ingle Responsibility Principle pen Closed Principle iskov Substitution Principle nterface Segregation Principle ependency Inversion Principle S O L I D Eine Klasse sollte offen für Erweiterungen, jedoch geschlossen für Modifikationen sein. Quelle: http://www.clean-code-developer.de/
15. ingle Responsibility Principle pen Closed Principle iskov Substitution Principle nterface Segregation Principle ependency Inversion Principle S O L I D Abgeleitete Klassen sollten sich so verhalten wie es von ihren Basistypen erwartet wird. Quelle: http://www.clean-code-developer.de/
16. ingle Responsibility Principle pen Closed Principle iskov Substitution Principle nterface Segregation Principle ependency Inversion Principle S O L I D Interfaces sollten nur die Funktionalität wiederspiegeln die ihre Klienten erwarten. Quelle: http://www.clean-code-developer.de/
17. ingle Responsibility Principle pen Closed Principle iskov Substitution Principle nterface Segregation Principle ependency Inversion Principle S O L I D High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen. Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Abstraktionen. Quelle: Wikipedia.org
18. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen. Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Interfaces.
19. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein… Klient Leistungs- träger High-Level Low-Level
20. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein… Klient Leistungs- träger High-Level Low-Level … … …
21. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein… Person Bauer High-Level Low-Level Süßer Apfel
22. Person Boskoop Bauer High-Level Low-Level Süßer Apfel GetBoskoop ! High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein…
23. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen. Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Interfaces.
24. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen. Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Interfaces.
25. Person Boskoop Bauer High-Level Low-Level Süßer Apfel GetBoskoop High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen… !
26. Person Obsthändler Pink Lady Bauer Boskoop Bauer Granny Smith Bauer High-Level Low-Level Süßer Apfel High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen…
27. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen. Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Abstraktionen.
28. High-Level Klassen sollen nicht von Low-Level Klassen abhängig sein, sondern beide von Abstraktionen. Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Abstraktionen.
29. Person Obsthändler Pink Lady Bauer Boskoop Bauer Granny Smith Bauer High-Level Low-Level Süßer Apfel Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Abstraktionen. GetBoskoop !
30. Person Obsthändler High-Level Low-Level Süßer Apfel Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Abstraktionen. GetApfel Pink Lady Bauer Boskoop Bauer Granny Smith Bauer
31. Person IObsthändler Low-Level GetApfel Obsthändler B Obsthändler A Obsthändler C Süßer Apfel Abstraktionen sollen nicht von Details abhängig sein, sondern Details von Abstraktionen. High-Level
32. Was ist Inversion of Control??? Person IObsthändler Low-Level GetApfel Obsthändler B Obsthändler A Obsthändler C Süßer Apfel
33. ohne IoC mit IoC
34. DIP IoC Low-Level Creation Inversion Flow Inversion Interface Inversion
35. DIP IoC Low-Level Creation Inversion Flow Inversion Interface Inversion
36. Flow Inversion
37. Publisher Subscriber Flow Inversion
38. Subscriber Subscriber Publisher Publisher Publisher Event Aggregator Subscriber Flow Inversion
39. DIP IoC Low-Level Creation Inversion Flow Inversion Interface Inversion
40. Request Factory Typdefinition Creation Inversion Request Typdefinition
41. Subscriber Subscriber Request IoC Container Typdefinitionen Creation Inversion
42. public class StudentContext : DbContext { public StudentContext() : base() {} public DbSet<StudentEntity> Students { get; set; } } Creation Inversion
43. public class StudentContext : DbContext, IStudentContext { public StudentContext() : base() {} public DbSet<StudentEntity> Students { get; set; } } public class IStudentContext { DbSet<StudentEntity> Students { get; set; } } Creation Inversion
44. Creation Inversion public class StudentManagementViewModel { StudentContext context; public StudentEntity Student { get; set; } public StudentManagementViewModel() { this.context = new StudentContext(); } public void ShowStudent(string name) { this.Student = this.context.Students.FirstOrDefault<StudentEntity> (s => s.StudentName == name); } }
45. Creation Inversion public class StudentManagementViewModel { IStudentContext context; public StudentEntity Student { get; set; } public StudentManagementViewModel() { this.context = ServiceLocator.Create<IStudentContext>(); } public void ShowStudent(string name) { this.Student = this.context.Students.FirstOrDefault<StudentEntity> (s => s.StudentName == name); } }
46. Creation Inversion public class StudentManagementViewModel { IStudentContext context; public StudentEntity Student { get; set; } public StudentManagementViewModel(IStudentContext context) { this.context = context; } public void ShowStudent(string name) { this.Student = this.context.Students.FirstOrDefault<StudentEntity> (s => s.StudentName == name); } }
47. DIP IoC Low-Level Creation Inversion Flow Inversion Interface Inversion
48. public class StudentContext : DbContext, IStudentContext { public StudentContext() : base() {} public DbSet<StudentEntity> Students { get; set; } } public class IStudentContext { DbSet<StudentEntity> Students { get; set; } } Interface Inversion
49. public class IStudentRepository { IQueryable<StudentEntity> Students { get; set; } } Interface Inversion public class StudentContext : DbContext, IStudentRepository { public StudentContext() : base() { // ... } private DbSet<StudentEntity> students; public IQueryable<StudentEntity> Students { get{ return this.students} } }
50. [Table("StudentInfo")] public class StudentEntity { public StudentEntity() { } [Key] public int SID { get; set; } [Column("Name", TypeName = "ntext")] [MaxLength(20)] public string StudentName { get; set; } [Column("BDate", TypeName = "datetime")] public DateTime BirthDate { get; set; } [NotMapped] public int? Age { get;} } Interface Inversion
51. public class Student { public int SID { get; set; } public string Name { get; set; } public DateTime BirthDate { get; set; } public int? Age { get; } } Interface Inversion public class IStudentRepository { IQueryable<Student> Students { get; set; } } [Table("StudentInfo")] public class StudentEntity { [Key] public int SID { get; set; } [Column("Name", TypeName = "ntext")] [MaxLength(20)] public string StudentName { get; set; } [Column("BDate", TypeName = "datetime")] public DateTime BirthDate { get; set; } }
52. Interface Inversion public class StudentManagementViewModel { IStudentContext context; public StudentEntity Student { get; set; } public StudentManagementViewModel(IStudentContext context) { this.context = context; } public void ShowStudent(string name) { this.Student = this.context.Students.FirstOrDefault<StudentEntity> (s => s.StudentName == name); } }
53. Interface Inversion public class StudentManagementViewModel { IStudentRepository repository; public Student Student { get; set; } public StudentManagementViewModel(IStudentRepository repository) { this.repository = repository; } public void ShowStudent(string name) { this.Student = this.repository.Students.FirstOrDefault<Student> (s => s.StudentName == name); } }
54. var student = this.repository.Students.Single(s => s.StudentName == name); Student student = this.repository.Students.Single(s => s.StudentName == name); Student stud = this.repository.Students.Single(s => s.StudentName == name); Interface Inversion
55. Interface Inversion internal class StudentsFromDatabase : IManageStudents, DbSet {...} public class IStudentRepository { IQueryable<Student> Students { get; set; } } public interface IManageStudents : IQueryable<Student> { Student Create(); void Add(Student student); ... } Siehe auch: cessor.de this.Student = this.students.FirstOrDefault(s => s.StudentName == name);
56. Header Interfaces public interface IManageStudents : IQueryable<Student> { Student Create(); Student GetStudent(string name) void Add(Student student); ... } public class IStudentContext { DbSet<StudentEntity> Students { get; set; } } Role Interfaces Interface Inversion
57. DIP IoC Low-Level Creation Inversion Flow Inversion Interface Inversion
58. User Interface Business Layer Data Access Layer Cross Cutting Concerns
59. Quelle: http://jeffreypalermo.com/blog/the-onion-architecture-part-1/ Application Services Domain Services Domain Model User Interface File DB Web Service
60. • • • •
61. „The real problem is that programmers have spent far too much time worrying about efficiency in the wrong places and at the wrong times; premature optimization is the root of all evil (or at least most of it) in programming.“ Quelle: https://en.wikiquote.org/wiki/Donald_Knuth Donald Knuth
62. Der Code bestimmt die Lösung. Der Konsument bestimmen den Code.