/13/ design patterns: model view controller (mvc)

• separate an application or part of an application into three classes:
  • model: stores data and implements behaviour
  • view: renders the model (e.g., onscreen display)
  • controller: modifies model based on user input
• gained wide popularity through the Smalltalk language
• has been adapted to many languages
• no single agreed-upon implementation standard
• model and view implementation seems to be relatively obvious
• integration of the controller is the main point of dispute
• in Java, view and controller are often combined into a single class (controller is an inner class of the view)
• find the implementation that works for you
• my approach most closely matches john hunt's, as described here:
  http://www.jaydeetechnology.co.uk/planetjava/tutorials/swing/Model-View-Controller.PDF
• ActionScript lacks:
  • a general event listening architecture
  • UI component event listening
• ActionScript has:
  • manually created UI that may not fit into an application's class structure
  • both procedural and oop traditions
• hence, MVC in Flash is very open-ended...lots of possible implementations
• we'll study my interpretation of MVC in ActionScript
• for more ideas from other sources, see:
  • Steve Burbeck's canonical Applications Programming in Smalltalk-80(TM): How to use Model-View-Controller (MVC)
  • You've got the model-view-controller (excellent article with complete example source in Java)
  • Implementing The Model-View-Controller Paradigm using Observer and Observable
  • The Model-View-Controller Architecture
  • Sun's Java BluePrints: Model-View-Controller
  • Model View Controller Pattern (extended Java examples)
• a few benefits of mvc:
  • Allows multiple views of the same information
  • UI source can be modified without requiring changes to the application logic
  • UI can be swapped or removed at runtime
  • Easy to add new views
  • Makes code easier to manage and understand
  • Program modules can be developed in parallel after exposed methods have been defined
  • Reuse: one view might be used with many different models