ActionScript Design Patterns

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This course review design patterns in ActionScript3 as well as two known MVC platforms for Actionscript: PureMVC and Corringham

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ActionScript Design Patterns

  1. 1. Actionscript3 Design Patterns
  2. 2. Quick Overview <ul><li>You’re going to learn about a number of design patterns. </li></ul><ul><li>You’re going to work out some of them in code. </li></ul><ul><li>You’re going to apply most of the patterns we learn today towards an example Model View Controller application </li></ul>
  3. 3. Design Patterns… <ul><li>Are reusable solutions to common design problems </li></ul><ul><li>Improve the development workflow </li></ul><ul><li>Help teams to work together efficiently </li></ul><ul><li>Help you deal with change </li></ul>
  4. 4. Design Patterns… <ul><li>are not Algorithms </li></ul><ul><li>are not Architectural Patterns </li></ul><ul><li>are not finished designs </li></ul><ul><li>are not written in stone </li></ul>
  5. 5. Singleton Pattern <ul><li>The one and only </li></ul>
  6. 6. The Singleton Pattern… <ul><li>has only ONE instance ever </li></ul><ul><li>is created only when needed </li></ul><ul><li>assures that every object in an application is using the same resource (global access point) </li></ul>
  7. 7. SINGLETON PATTERN LAB
  8. 8. Singleton Pattern Tips <ul><li>Use this pattern when you need one and only one instance of a class </li></ul><ul><li>The package mx.managers are all singletons </li></ul><ul><ul><li>DragManager </li></ul></ul><ul><ul><li>CursorManager </li></ul></ul><ul><ul><li>HistoryManager </li></ul></ul><ul><ul><li>FocusManager </li></ul></ul><ul><ul><li>etc… </li></ul></ul>
  9. 9. COMMAND PATTERN <ul><li>Execute Here  </li></ul>
  10. 10. The Command Pattern… <ul><li>encapsulates method invocation. </li></ul><ul><li>is used to carry out ‘orders’ like </li></ul><ul><ul><li>authenticate user </li></ul></ul><ul><ul><li>process form </li></ul></ul><ul><ul><li>sit on cat </li></ul></ul><ul><li>often encapsulates an algorithm. </li></ul><ul><li>often performs tricky operations. </li></ul>
  11. 11. Command Pattern Lab
  12. 12. OBSERVER PATTERN
  13. 13. The Observer Pattern… <ul><li>defines a one to many relationship between objects so when one object changes, all the observers are notified. </li></ul><ul><li>is also known as Publish and Subscribe. </li></ul><ul><li>is used in event driven design. </li></ul><ul><li>reduces coupling between classes, but they can still interact. </li></ul>
  14. 14. Observer Pattern Lab In this lab, we’re going to leverage the Observer Pattern implementation built into the Flash Player. Event Dispatcher Observer Observer Observer
  15. 15. PROXY PATTERN
  16. 16. A Proxy… <ul><li>stands in for and provides access to another object. </li></ul><ul><li>can control or guard access </li></ul><ul><li>can be used to manage instantiation </li></ul>
  17. 17. The Virtual Proxy <ul><li>The Virtual Proxy stands in for an object that </li></ul><ul><li>is expensive to create </li></ul><ul><li>is not immediately available </li></ul><ul><li>The Loader class is a Virtual Proxy. </li></ul>DisplayObjectContainer Loader Sprite Stage MovieClip
  18. 18. The Remote Proxy <ul><li>The Remote Proxy stands in for a remote object and, </li></ul><ul><li>delegates requests to a remote object </li></ul><ul><li>manages communication with remote object </li></ul>Image Search Flickr API Remote PhotoProxy Remote Service Your Application
  19. 19. Proxy Pattern Lab <ul><li>In this lab, we’re going to implement a remote proxy and learn about a time saving technique. </li></ul>Image Search Flickr API Remote PhotoProxy Remote Service Your Application
  20. 20. FAÇADE PATTERN <ul><li>Hiding Complexity </li></ul>
  21. 21. Façade Pattern… <ul><li>The Façade pattern simplifies access to a collection of objects. </li></ul><ul><li>Often implemented as a singleton (only need one) </li></ul><ul><li>Hides the complexity of underlying objects </li></ul>Application Facade Model View Controller
  22. 22. ADAPTER PATTERN <ul><li>a.k.a. Wrapper </li></ul>
  23. 23. Adapter Pattern… <ul><li>The Adapter pattern converts and translates the API of one object to the API of another object. </li></ul><ul><li>often applied when reusing legacy code </li></ul><ul><li>providing a common API to several 3 rd party libraries or algorithms </li></ul>Music Player MP3 Adapter FLAC Adapter AC3 Adapter FLAC Decoder MP3 Decoder WAV Decoder
  24. 24. Mediator Pattern <ul><li>Central Communication </li></ul>
  25. 25. Mediator Pattern <ul><li>The Mediator Pattern is used to centralize complex communication and control between related objects. </li></ul>Application Username Textbox Password Textbox Submit Button New Account Form Account Form Mediator
  26. 26. MODEL VIEW CONTROLLER <ul><li>A collection of patterns </li></ul>
  27. 27. Model View Controller (MVC) <ul><li>The MVC Pattern is a collection of patterns used to address the challenges presented by rich user interfaces. </li></ul>
  28. 28. Model View Controller (MVC) <ul><li>MVC brings order to applications and application development by, </li></ul><ul><li>decoupling the user interface of an application from the data model and business logic. </li></ul><ul><li>allow each of the elements to be changed without impacting the other. </li></ul><ul><li>improve communication and understanding between developers so they can work independently and more efficiently. </li></ul>
  29. 29. Quick Comparison <ul><li>Model </li></ul><ul><li>View </li></ul><ul><li>Controller </li></ul><ul><li>Command </li></ul><ul><li>Façade </li></ul><ul><li>Proxy </li></ul><ul><li>Mediator </li></ul><ul><li>Observer </li></ul><ul><li>Notification </li></ul><ul><li>Model </li></ul><ul><li>View </li></ul><ul><li>Controller </li></ul><ul><li>Command </li></ul><ul><li>Delegate </li></ul><ul><li>Service </li></ul><ul><li>CairngormEvent </li></ul>Cairngorm
  30. 30. What I Like About PureMVC <ul><li>Platform independent (AS2, AS3, Coldfusion, Java, C#, Perl, Python, PHP, Ruby) </li></ul><ul><li>Excellent Documentation and Active Development Community </li></ul><ul><li>Winner at SilvaFUG between 9 frameworks </li></ul>Cairngorm
  31. 31. PureMVC Conceptual Diagram
  32. 32. DSP-IP Contact information Download slides at: www.dsp-ip.com Course materials & lecture request Projects development services: Adi Yakov Training Manager [email_address] +972-9-8651933 www.dsp-ip.com Mail : [email_address] Phone: +972-9-8850956, Fax : +972-50- 8962910 <ul><ul><li>Alona Ashkenazi </li></ul></ul><ul><li>Development Services </li></ul><ul><li>[email_address] +972-9-8850956 </li></ul>

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