The document provides an introduction to aspect-oriented programming with .NET. It discusses various cross-cutting concerns like logging, exceptions, validation, and caching that can be addressed using aspect-oriented programming. It also demonstrates how aspects are used to modify the intermediate language (IL) code to inject cross-cutting behavior before, after, and around method calls. Various aspect oriented programming frameworks for .NET are also mentioned.

1. AspektOrientierteProgrammierungmit .NET Eine praktische Einführung 27.06.2011 Dipl.-Inf. (FH) Johannes Hoppe

2. Johannes Hoppe ASP.NET MVC Webentwickler www.johanneshoppe.de

3. 01 Architektur und Patterns

4. Patterns Entwurfsmuster == unser täglicher Job

5. Beispiel

6. Aber…

7. Business Code publicclassCustomerProcesses { publicvoid RentBook( int bookId, int customerId ) { Book book = Book.GetById( bookId ); Customer customer = Customer.GetById( customerId ); book.RentedTo = customer; customer.AccountLines.Add(string.Format( "Rental of book {0}.", book ), book.RentalPrice ); customer.Balance -= book.RentalPrice; } }

8. Business Code + Logging internalclassCustomerProcesses { privatestaticreadonlyTraceSource trace = newTraceSource( typeof (CustomerProcesses).FullName ); publicvoid RentBook( int bookId, int customerId ) { trace.TraceInformation( "Entering CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )", bookId, customerId ); try{ Book book = Book.GetById( bookId ); Customer customer = Customer.GetById( customerId ); book.RentedTo = customer; customer.AccountLines.Add( string.Format( "Rental of book {0}.", book ), book.RentalPrice ); customer.Balance -= book.RentalPrice; trace.TraceInformation( "Leaving CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )", bookId, customerId ); } catch ( Exception e ) { trace.TraceEvent( TraceEventType.Error, 0, "Exception: CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} ) failed : {2}", bookId, customerId, e.Message ); throw; } } }

9. Business Code internalclassCustomerProcesses { privatestaticreadonlyTraceSource trace = newTraceSource(typeof(CustomerProcesses).FullName); publicvoid RentBook(int bookId, int customerId) { if (bookId <= 0) thrownewArgumentOutOfRangeException("bookId"); if (customerId <= 0) thrownewArgumentOutOfRangeException("customerId"); trace.TraceInformation( "Entering CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )", bookId, customerId); try { Book book = Book.GetById(bookId); Customer customer = Customer.GetById(customerId); book.RentedTo = customer; customer.AccountLines.Add(string.Format("Rental of book {0}.", book), book.RentalPrice); customer.Balance -= book.RentalPrice; trace.TraceInformation( "Leaving CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )“, bookId, customerId); } catch (Exception e) { trace.TraceEvent(TraceEventType.Error, 0, "Exception: CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} ) failed : {2}", bookId, customerId, e.Message); throw; } } } + Logging + Vorbedingungen

10. Business Code + Logging+ Transaktionen + Vorbedingungen internalclassCustomerProcesses { privatestaticreadonlyTraceSource trace = newTraceSource(typeof(CustomerProcesses).FullName); publicvoid RentBook(int bookId, int customerId) { if (bookId <= 0) thrownewArgumentOutOfRangeException("bookId"); if (customerId <= 0) thrownewArgumentOutOfRangeException("customerId"); trace.TraceInformation( "Entering CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )“, bookId, customerId); try { for (int i = 0; ; i++) { try { using (var ts = newTransactionScope()) { Book book = Book.GetById(bookId); Customer customer = Customer.GetById(customerId); book.RentedTo = customer; customer.AccountLines.Add(string.Format("Rental of book {0}.", book), book.RentalPrice); customer.Balance -= book.RentalPrice; ts.Complete(); } break; } catch (TransactionConflictException) { if (i < 3) continue; else throw; } } trace.TraceInformation( "Leaving CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )", bookId, customerId); } catch (Exception e) { trace.TraceEvent(TraceEventType.Error, 0, "Exception: CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} ) failed : {2}", bookId, customerId, e.Message); throw; } } }

11. Business Code + Logging+ Transaktionen + Vorbedingungen + Exception Handling internalclassCustomerProcesses { privatestaticreadonlyTraceSource trace = newTraceSource(typeof(CustomerProcesses).FullName); publicvoid RentBook(int bookId, int customerId) { if (bookId <= 0) thrownewArgumentOutOfRangeException("bookId"); if (customerId <= 0) thrownewArgumentOutOfRangeException("customerId"); try { trace.TraceInformation( "Entering CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )", bookId, customerId ); try { for ( int i = 0;; i++ ) { try { using ( var ts = newTransactionScope() ) { Book book = Book.GetById( bookId ); Customer customer = Customer.GetById( customerId ); book.RentedTo = customer; customer.AccountLines.Add( string.Format( "Rental of book {0}.", book ), book.RentalPrice ); customer.Balance -= book.RentalPrice; ts.Complete(); } break; } catch ( TransactionConflictException ) { if ( i < 3 ) continue; else throw; } } trace.TraceInformation( "Leaving CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} )", bookId, customerId ); } catch ( Exception e ) { trace.TraceEvent( TraceEventType.Error, 0, "Exception: CustomerProcesses.CreateCustomer( bookId = {0}, customerId = {1} ) failed : {2}", bookId, customerId, e.Message ); throw; } } catch ( Exception e ) { if (ExceptionManager.Handle(e)) throw; } } }

12. Business Code + Logging+ Transaktionen + Vorbedingungen + Exception Handling + Feature X + Feature Y + Feature Z + …

13. Kern-funktionalitäten (Core Concerns) SeperationofConcerns

14. VS

15. VS Nicht-Funktionale Anforderungen(CrosscuttingConcerns)

16. Cross-CuttingConcerns Data Binding Thread Sync Caching Validation … Security Exception Handling Tracing Monitoring Transaction

17. OOP OOP+ AOP

18. Spring.NET Castle MS Unity PostSharp LinFu Build-Time Run-Time Hybrid

19. Erfolgt zur Laufzeit Code bleibt unverändert Aufruf wird über Proxy umgeleitet Zur Laufzeit keine Änderungen Aufruf wird über Proxyumgeleitet Aspekte zur Laufzeitkonfigurierbar Erfolgt bei Kompilierung Code wird direkt verändert Keine Interfaces erforderlich Zur Laufzeit keine Änderungen Auch auf Properties, Felder,Events anwendbar Kann Member und Interfaces hinzufügen Build-Time: “Statisch” Run-Time: “Dynamisch”

20. 02 Live Coding

22. Logging LogTimeAspect webnoteaop.codeplex.com

23. Exceptions ConvertExceptionAspect webnoteaop.codeplex.com

24. Validierung ValidationGuardAspect webnoteaop.codeplex.com

25. Caching SimpleCacheAspect webnoteaop.codeplex.com

27. 03 AOP 1 x 1

28. AspectJ Begriffe Join Point Pointcut Advice Aspect

29. AspectJ Begriffe Join Point Pointcut Advice Aspect

30. IL Code Vorher [LogTimeAspect] publicActionResult Index() { IEnumerable<NoteWithCategories> notes = this.WebNoteService.ReadAll(); return View(notes); }

31. IL Code Nachher publicActionResult Index() { ActionResult CS$1$2__returnValue; MethodExecutionArgs CS$0$3__aspectArgs = new MethodExecutionArgs(null, null); <>z__Aspects.a68.OnEntry(CS$0$3__aspectArgs); try { IEnumerable<NoteWithCategories> notes = this.WebNoteService.ReadAll(); ActionResult CS$1$0000 = base.View(notes); CS$1$2__returnValue = CS$1$0000; } finally { <>z__Aspects.a68.OnExit(CS$0$3__aspectArgs); } return CS$1$2__returnValue; }

32. OriginaleMethode Aspect Klasse OnEntry try{} catch (Exception e){}finally{} Method Body OnSuccess OnException OnExit : OnMethodBoundaryAspect

33. Links Spring.NET springframework.net Castle castleproject.org Unity unity.codeplex.com PostSharp sharpcrafters.com Demo Download webnoteaop.codeplex.com

34. FRAGEN?

35. Vielen Dank! Johannes Hoppe

36. Aspect- Typen MethodBoundaryAspect OnEntry OnSuccess OnException OnExit OnExceptionAspect OnException MethodInterceptionAspect OnInvoke LocationInterceptionAspect OnGetValue OnSetValue EventInterceptionAspect OnAddHandler OnRemoveHandler OnInvokeHandler MethodImplementationAspect OnInvoke CompositionAspect CreateImplementationObject

37. Bildnachweise Ausgewählter Ordner © Spectral-Design – Fotolia.com Warnhinweis-Schild © Sascha Tiebel – Fotolia.com Liste abhaken © Dirk Schumann – Fotolia.com 3D rendering of an architecture model 2 © Franck Boston – Fotolia.com Healthcare © ArtmannWitte – Fotolia.com Stressed businessman © Selecstock – Fotolia.com

38. Farben Primär

39. Farben Code