Minimalist Example of an MVC Pattern | 433TheModel class extends theEventDispatcher class that already implements the
IEventDispatcher interface. Note the dispatchEvent( ) function call within the
setKey( )method. This sends aCHANGEevent to all registered observers when the
value oflastKeyPressed is changed within thesetKey( ) method.
Controller as a Concrete Strategy in a Strategy Pattern
The relationship between the controller and view is that of strategy and context in a
strategy pattern. Each controller will be a concrete strategy implementing a required
behavior defined in a strategy interface.
The controller
For our minimalist example, the behavior required of the controller is to handle a
key press event.IKeyboardInputHandleris the strategy interface (Example 12-3), and
defines a single method calledkeyPressHandler( ).
The concrete controller is theControllerclass (Example 12-4) that implements the
IKeyboardInputHandler interface.
private var lastKeyPressed:uint = 0;
public function setKey(key:uint):void
{
this.lastKeyPressed = key;
dispatchEvent(new Event(Event.CHANGE)); // dispatch event
}
public function getKey( ):uint
{
return lastKeyPressed;
}
}
}
Example 12-3. IKeyboardInputHandler.as
package
{
import flash.events.*;
public interface IKeyboardInputHandler
{
function keyPressHandler(event:KeyboardEvent):void
}
}
Example 12-2. Model.as (continued)