Presentation on getting started with the Swiz framework for Adobe Flex. It concentrates on solving problems around IoC, dependency injection, event handling and interacting with external services.

1. Introduction to Swiz It’s easy. Seriously.No, I mean it. It is. 1 Nicholas Tunney

2. Session Goals What problems are we trying to solve? How do I set up Swiz? How do I put Swiz to work for me? Where else can I learn about Swiz? 2

3. What problems are we trying to solve? 3

4. Inversion of Control Decentralize application control Provide for actions on setup and teardown Separate the WHAT from the WHEN 4

5. Inversion of Control DANGER! 5 Courtesy of Joam Tall (Flickr)

6. Dependency Injection Objects are dependent on other objects Objects need those objects to be created (instantiated) to perform a task Objects that handle their own object creation are said to be ‘tightly coupled’ A simple change to the program results in major code changes, just not flexible Problem is best illustrated with an example 6

7. Dependency Injection public class Boat { private varengine:Engine= new Merc230(); public function boat () { } cruise (int RPM):String { engine.go(RPM); return engine.thrillFactor; } } 7

8. Dependency Injection public class Boat { private var_engine:Engine; public function boat () { } set Engine (engine:Engine):void { _engine = engine; } cruise (int RPM):String { _engine.go(RPM); return _engine.thrillFactor; } } 8

9. Dependency Injection myBoat:IBoat = new Boat(); myEngine:IEngine = new Merc230(); myBoat.setEngine(myEngine); myBoat.go(3000) // ‘w00t!’ myNewEngine:IEngine = new Merc57(); myBoat.go(3000) // ‘YEEEHHHHHAAAA!!!’ 9

10. Dependency Injection Can see how powerful dependency injection can be Can do that in various places across files (still lots of code to change, or via configuration using a framework like Swiz (one file to change) 10

11. Singletons Create once, use everywhere Low overhead, single instantiation Swiz is used to create these objects, and handle keeping state across the application 11

12. Creation of Transient Objects Swiz permits Prototyping objects Acts like an object factory Ask Swiz for an object, it injects dependencies and hands you a single instance of that object Not persistent 12

13. Event Handling We react to events in the application and perform tasks (WHAT versus WHEN) Event handling in Flex can be a nightmare challenge Events need to be dispatched from non-display objects to varied display objects Events need to be dispatched from display objects to non-display objects like controllers or their presentation models I want to fire an event ANYWHERE in my Flex application, and mediate it ANYWHERE in my Flex application 13

14. Interaction with External Services Every Flex app I have written (except 1) has interacted with external services, it’s the way of the web anymore Each external service call has a set signature and workflow Writing this workflow for every call is tedious, or moreover redundant 14

15. How do I set up Swiz? 15

16. Grab the SWC http://www.swizframework.org Place correct swc in /lib directory 16

17. SwizConfig Brutally simple, just like the framework Can simply copy/paste A few knobs to turn 17

18. SwizConfig <swiz:config> <swiz:SwizConfig setUpEventType="{ Event.ADDED_TO_STAGE }" setUpEventPhase="{ EventPhase.CAPTURING_PHASE }" setUpEventPriority="50" tearDownEventType="{ Event.REMOVED_FROM_STAGE }" tearDownEventPhase="{ EventPhase.CAPTURING_PHASE }" tearDownEventPriority="50" eventPackages="com.foo.event.*, org.bar.event.*" viewPackages="com.foo.view.*, org.bar.view.*" defaultFaultHandler="handleUnhandledFaults" defaultDispatcher="global" /> </swiz:config> 18

19. SwizConfig <swiz:config> <swiz:SwizConfig eventPackages="com.foo.event.*, org.bar.event.*" viewPackages="com.foo.view.*, org.bar.view.*” /> </swiz:config> 19

20. Logging Target I do not write perfect code, I need to log – a lot Built in logging for Swiz to console Can override and customize by extending the AbstractSwizLoggingTarget class <swiz:loggingTargets> <swiz:SwizTraceTarget id="myTraceTarget" /> </swiz:loggingTargets> 20

21. Stuff We Didn’t Do Verbose configuration Force the usage of J2EE patterns Have to define any special directory structure Tightly couple Swiz to our code (except with ServiceHelper and command chain) – no extending framework classes, etc) Take more than 5 minutes to review the Quickstart ;) 21

22. How do I put Swiz to work for me? 22

23. Review of Problems We Are Solving Inversion of Control Dependency Injection Singletons Creation of Transient Objects (Factory) Event Handling Interaction with External Services 23

24. Inversion of Control Permits us to define and declare dependencies: Controllers – for server interaction Model Delegates Services 24

25. Dependency Injection IoC container is defined by BeanProviders Define non-view classes Once defined, they can all be injected into your UI, presentation model, controllers, etc Can define in main application file, best practice to define and include <- but Swiz doesn’t try to force you to do this ;) - Use the <swiz:Bean /> tag 25

26. Dependency Injection Beans.mxml – or whatever you call it <swiz:BeanProvider xmlns:swiz=" xmlns:service="org.swizframework.quickswiz.service.*" xmlns:controller="org.swizframework.quickswiz.controller.*"> <service:UserService id="userService"/> <controller:UserController id="userController"/> <!-- We'll use the SwizServiceHelper to help simulate a server-side call. --> <swiz:ServiceHelper id="serviceHelper" /> </swiz:BeanProvider> 26

27. Dependency Injection So how do we inject these objects? METADATA! (Note that Swiz can inject into public properties only) Inject by type (preferred) [Inject] variableName:Type Inject by name [Inject (“myService”)] variableName:RemoteObject; 27

28. Dependency Injection Can also inject a bean property [Inject (“ApplicationConfig.mode”)] currMode:String; Or provide a destination [Inject ( source=“ApplicationConfig.mode”, destination=“presentationModel.mode” ) ] 28

29. Dependency Injection Setter Injection is also possible [Inject] public function setModel (model:UserModel):void { … } 29

30. Singletons All objects created in the beans.mxmlas described are officially singletons This statement is not true for prototype objects BEAN LIFECYCLE 30

31. Bean LifeCycle [PostConstruct] [PreDestroy] 31

32. Creation of Transient Objects New object created for each request Much like an object factory Can send in properties via configuration as well <swiz:Prototype id=”User" type="{ User }" constructorArguments="{ someOtherBean }" /> 32

33. Event Handling Event mediation – decouples the WHAT from the WHEN Code the WHAT Wire the WHEN 33

34. Event Handling Two things we care about Dispatching events Mediating events 34

35. Event Handling Dispatching Events From a UIComponent dispatchEvent() important! The event must bubble! Swiz listens in the root container From other objects Inject a dispatcher [Dispatcher] Variable should have a type of IEventDispatcher Swiz handles the dependency injection 35

36. Event Handling Mediating Events Sooooooo easy! This was my aha moment for using a Flex framework 36

37. Event Handling Simple Event Mediation We can do this since we defined event packages Otherwise, specify fully qualified classname [EventHandler( event=“EventClass.EVENT_CONSTANT” )] public function myEventHandler (event:Event): void { … } 37

38. Event Handling Swiz inspects the handler and reacts accordingly (note there is no event property in this method) [EventHandler( event=“EventClass.EVENT_CONSTANT” )] public function myEventHandler (): void { … } 38

39. Event Handling Grab properties from the event (note that we can now explicitly call this method outside of an event) [EventHandler( event=“MyEvent.EVENT”, properties=“user” )] public function myEventHandler (user:User): void { … } 39

40. Event Handling Mediate multiple events with the same handler [EventHandler( event=“MyEvent.EVENT”] [EventHandler( event=“MyEvent.OTHER_EVENT”] public function myEventHandler (): void { … } 40

41. Interaction with External Services Swiz provides beans for Async and other services Async: ServiceHelper Non Async: URLRequestHelper 41

42. Interaction with External Services ServiceHelper Define the bean Inject the bean Call the service Handle the results 42

43. Interaction with External Services Define the ServiceHelper bean <swiz:ServiceHelper id="serviceHelper" /> Inject the bean [Inject] public varsh:ServiceHelper; Call the service sh.executeServiceCall(ro.method(), resultHandler, faultHandler); 43

44. Demo Demonstrates everything we have talked about today, plus supports the Cat Internet meme. 44

45. Bonus: Client Persistence SharedObject- Provides methods for storing items <swiz:BeanProvider xmlns:swiz=" xmlns:storage="org.swizframework.storage.*”> <storage:SharedObjectBean id="soBean" /> </swiz:BeanProvider> 45

46. Bonus: Client Persistence Using the SharedObject bean [Inject] public varso:ISharedObjectBean; [Bindable] public function get appIndex():int { // the second parameter is the initial value return so.getInt("appIndex", 0); } public function set appIndex(index:int):void { so.setInt("appIndex", index); } 46

47. Where else can I learn about Swiz? 47

48. Continued Learning http://swizframework.org Starting point for everything Wiki – everything in this preso is on the wiki Quickstart Configuration FAQ Everything else @swizframework Google Group – groups.google.com/group/swiz-framework 48

49. 49 Thanks! @ntunney blog.nictunney.com nic.tunney@nictunney.com bind53@gmail.com