List of Listings

Chapter 1. Introducing AOP

Listing 1.1. A simple program that calls service methods in sequence

Listing 1.2. Example of refactoring using DI instead of AOP

Listing 1.3. Use of the decorator pattern in pseudocode

Listing 1.4. Using AOP instead of DI for cross-cutting concerns

Listing 1.5. Pseudocode example of an extremely simple AddressBookService

Listing 1.6. Pseudocode example with argument checking split out using AOP

Listing 1.7. Encapsulated and reusable code

Chapter 2. Acme Car Rental

Listing 2.1. An implementation of the accrual service

Listing 2.2. A simple Console application to test the business logic

Listing 2.3. Accrue code, now with logging

Listing 2.4. Redeem code, now with logging

Listing 2.5. Accrue with defensive programming

Listing 2.6. Redeem with defensive programming

Listing 2.7. Accrue with a transaction

Listing 2.8. Redeem with a transaction

Listing 2.9. Accrue with transaction and retries

Listing 2.10. Redeem with transaction and retries

Listing 2.11. Accrue with exception handling

Listing 2.12. Redeem with exception handling

Listing 2.13. Redemption service refactored with DI

Listing 2.14. Accrual service refactored with DI

Listing 2.15. Combined exception handler and transaction handler

Listing 2.16. An aggregate service for orchestrating two services

Listing 2.17. Accrue method’s defensive programming and logging

Listing 2.18. A method boundary aspect to handle logging

Listing 2.19. Applying the logging aspect to the Accrue and Redeem methods

Listing 2.20. Examining and logging argument value

Listing 2.21. An alternative way to log certain entities

Listing 2.22. A defensive programming aspect

Listing 2.23. Refactoring to aspects with an attribute

Listing 2.24. A transaction aspect

Listing 2.25. Continuing to refactor with aspects

Listing 2.26. An aspect to handle exceptions

Listing 2.27. All cross-cutting concerns refactored into aspects

Chapter 3. Call this instead: intercepting methods

Listing 3.1. Calling Send method on TwitterClient service class

Listing 3.2. Indicating which method to intercept with an attribute

Listing 3.3. Calling the Send method on the TwitterClient service class

Listing 3.4. Adding code to the interceptor

Listing 3.5. Three different transaction scenarios

Listing 3.6. A Main method to try out the Save scenarios

Listing 3.7. Basic transaction interceptor, used with proxy generator

Listing 3.8. Using ProxyGenerator to apply the TransactionWithRetries aspect

Listing 3.9. Using Dispose to rollback

Listing 3.10. Adding a loop to retry

Listing 3.11. Transaction with maximum retries specified in constructor

Listing 3.12. Full Form1 class with button click event handler

Listing 3.13. Checking whether Invoke is necessary

Listing 3.14. Wouldn’t it be nice if threading were more like this?

Listing 3.15. UIThread interceptor aspect

Listing 3.16. Declarative threading is now a reality

Listing 3.17. Changing from Thread to Task

Chapter 4. Before and after: boundary aspects

Listing 4.1. Calling a GetBattingAverage method on a service class

Listing 4.2. Using an attribute to indicate which method to bound

Listing 4.3. Using a class member for shared state

Listing 4.4. A Console application showing the pitfalls of using an aspect field in PostSharp

Listing 4.5. Using MethodExecutionTag to share state

Listing 4.6. A boundary aspect that overrides only OnExit

Listing 4.7. An equivalent interception aspect

Listing 4.8. Configuring MyHttpModule in Web.config

Listing 4.9. Event handlers in MyHttpModule

Listing 4.10. Writing text to the response at the beginning and end of a page

Listing 4.11. Subscribing to the BeginRequest boundary event

Listing 4.12. A class to detect mobile users

Listing 4.13. Detecting a mobile browser

Listing 4.14. Basic splash screen with two buttons

Listing 4.15. Handling the button clicks in code-behind

Listing 4.16. Adding checks to avoid redirect loops

Listing 4.17. Checking for a cookie

Listing 4.18. CarValue.aspx HTML and ASP.NET controls

Listing 4.19. Add items to each drop-down list

Listing 4.20. An event to handle a button click

Listing 4.21. Show the entire contents of Cache

Listing 4.22. Clicking the Get Value button

Listing 4.23. Storing the results of the method in a cache

Listing 4.24. Naïve GetCacheKey implementation

Listing 4.25. Add an OnEntry override to the CacheAspect class

Listing 4.26. Checking the cache in OnEntry

Listing 4.27. Refactored CarValueService to encapsulate options

Listing 4.28. A more robust GetCacheKey using serialization

Chapter 5. Get this instead: intercepting locations

Listing 5.1. Encapsulation of a private field with methods

Listing 5.2. The compiled program viewed through the ILSpy tool

Listing 5.3. Using a method interception aspect on a property

Listing 5.4. Using a PostSharp location interception aspect

Listing 5.5. Lazy loading with a property and a backing field

Listing 5.6. Thread-safe lazy loading with double-checked locking

Listing 5.7. Using System.Lazy<T>

Listing 5.8. Basic Console application with no lazy loading

Listing 5.9. A lazy-loading aspect

Listing 5.10. Lazy loading using Activator

Listing 5.11. SlowConstructor with a dependency on IMyService

Listing 5.12. Initializing

Listing 5.13. Lazy loading with StructureMap

Listing 5.14. Using StructureMap in place of Activator

Listing 5.15. XAML to create textbox, button, and textblocks

Listing 5.16. A view model class representing the data

Listing 5.17. Binding a NameViewModel object to MainWindow’s DataContext

Listing 5.18. Binding controls to ViewModel properties

Listing 5.19. Implementing INotifyPropertyChanged on NameViewModel

Listing 5.20. Using CallerMemberName attribute

Listing 5.21. Boilerplate-free use of INotifyPropertyChanged

Listing 5.22. NameViewModel with a custom PostSharp aspect

Listing 5.23. Constructor that accepts derived property names

Listing 5.24. Perform all the steps of property notification in OnSetValue

Listing 5.25. RaisePropertyChanged method

Chapter 6. Unit testing aspects

Listing 6.1. Writing a test of the Reverse method

Listing 6.2. Testing for the presence of attributes

Listing 6.3. A static Log class

Listing 6.4. NUnit fixture to test MyInterceptor

Listing 6.5. Using Moq

Listing 6.6. MyOtherService service implementation and interface

Listing 6.7. LoggingService implementation and interface

Listing 6.8. MyLoggingAspect implementation

Listing 6.9. Testing MyLoggingAspect

Listing 6.10. MyService implementation and interface

Listing 6.11. Using MyService object in Main

Listing 6.12. Initializing and using StructureMap

Listing 6.13. One approach to using aspects with a complex domain

Listing 6.14. Using EnrichWith feature of StructureMap

Listing 6.15. More concise use of EnrichWith

Listing 6.16. ProxyHelper

Listing 6.17. A test of a PostSharp aspect

Listing 6.18. Program’s Main method

Listing 6.19. MyLoggingAspect with PostSharp

Listing 6.20. Dependency inversion via RuntimeInitialize

Listing 6.21. Creating an aspect object for the test

Listing 6.22. Call OnEntry and OnSuccess to execute the aspect

Listing 6.23. Verify that the logging operations happened

Listing 6.24. A class/method that reverses a string, and its unit test

Listing 6.25. Reverse method with aspect applied

Listing 6.26. Mocking ILoggingService to satisfy the aspect

Listing 6.27. Workaround with custom symbols

Listing 6.28. A global variable setting for unit testing

Listing 6.29. A thin aspect and the interface to which it’s delegating

Chapter 7. AOP implementation types

Listing 7.1. A Console program that uses a proxy generator

Listing 7.2. Creating an AssemblyBuilder and a ModuleBuilder

Listing 7.3. Define a Type and get a TypeBuilder

Listing 7.4. Define a field and get a FieldBuilder

Listing 7.5. Define a constructor and get an ILGenerator

Listing 7.6. Emitting CIL code for the constructor

Listing 7.7. Tweet method for the interface with an ILGenerator

Listing 7.8. Writing to Console and calling the real Tweet method with OpCodes

Listing 7.9. Introducing a PostSharp aspect

Listing 7.10. ILSpy decompile of MyClass

Chapter 8. Using AOP as an architectural tool

Listing 8.1. Logging the method that was called

Listing 8.2. Using Initialize to get the method name at compile time

Listing 8.3. A LocationInterceptionAspect to log usage of get

Listing 8.4. Using CompileTimeValidate to check the location name

Listing 8.5. Runtime checks on casting

Listing 8.6. Threading aspect of compile-time validation

Listing 8.7. Unsealable referential constraint

Listing 8.8. Unsealable demonstration

Listing 8.9. NHibernate ScalarConstraint

Listing 8.10. An NHibernate entity with a nonvirtual property

Listing 8.11. Excluding a member with AttributeExclude

Listing 8.12. AspectPriority for ordering

Listing 8.13. AttributeTargetElements to target only the instance constructor

Chapter 9. Aspect composition: example and execution

Listing 9.1. Multiple aspects on the same method

Listing 9.2. Specifying an aspect role

Listing 9.3. Specifying aspect role dependency

Listing 9.4. An aspect that requires another role

Listing 9.5. ProxyHelper from chapter 6

Listing 9.6. A demo class and two demo aspects

Listing 9.7. Use of multiple aspects on the same code in StructureMap

Listing 9.8. A StructureMap name-based convention for applying aspects

Listing 9.9. Added overloaded Proxify to ProxyHelper

Listing 9.10. Adding a convention to the assembly scanner

Listing 9.11. Using a namespace-based convention

Listing 9.12. Configure StructureMap with default conventions

Listing 9.13. Budget service, interface, and implementation

Listing 9.14. A static caching service

Listing 9.15. User repository

Listing 9.16. The main UI of the program

Listing 9.17. The main UI prepared for exception

Listing 9.18. Caching concern interface and constructor

Listing 9.19. OnEntry of the caching concern

Listing 9.20. Adapter interface to get method context

Listing 9.21. OnSuccess of the caching concern

Listing 9.22. Authorization concern interface and constructor

Listing 9.23. OnEntry of the authorization concern

Listing 9.24. PostSharp caching aspect

Listing 9.25. PostSharp method context adapter

Listing 9.26. PostSharp authorization aspect

Listing 9.27. Aspect composition of caching and authorization

Listing 9.28. DynamicProxy caching aspect Intercept code

Listing 9.29. Castle DynamicProxy method context adapter

Listing 9.30. Constructor and members of the Authorization interceptor

Listing 9.31. Authorization Intercept code

Listing 9.32. Another Proxify overload in ProxyHelper

Listing 9.33. Name a mapping for Manager authorization

Listing 9.34. Complete IoC initialization

Appendix A. Ecosystem of .NET AOP tools

Listing A.1. Simple LinFu example

Listing A.2. Modifying project file to add PostWeaveTask

Listing A.3. Simple SheepAspect example

Listing A.4. Simple MethodDecorator example

Listing A.5. A basic Castle Windsor and DynamicProxy example

Listing A.6. StructureMap interception

Listing A.7. Unity interception example

Listing A.8. Spring.NET example

Listing A.9. Spring.NET configuration