Ball.as

package {
	
	import flash.display.MovieClip;
	import flash.events.*;
	
	public class Ball extends MovieClip {
		
		private const speed:Number = 5;
		private var yDir:Number;
		private var xDir:Number;
		
		public function Ball() {
			this.addEventListener(Event.ENTER_FRAME, update);
			this.xDir = speed;
			this.yDir = speed;
		}
		
		public function impact():void {
			this.xDir = -this.xDir;
		}
		
		private function update(e:Event):void {
			this.y = this.y + this.yDir;
			this.x = this.x + this.xDir;
			
			if (this.x < 0) {
				dispatchEvent(new Event("P2_SCORE"));
				
				this.xDir = -this.xDir;
				this.x = this.stage.stageWidth / 2;
				this.y = this.stage.stageHeight / 2;
				
			} else if (this.x > this.stage.stageWidth) {
				dispatchEvent(new Event("P1_SCORE"));
				
				this.xDir = -this.xDir;				
				this.x = this.stage.stageWidth / 2;
				this.y = this.stage.stageHeight / 2;
			}
			
			if (this.y < 0) {
				this.yDir = -this.yDir;
				this.y = 0;
			} else if (this.y > this.stage.stageHeight) {
				this.yDir = -this.yDir;
				this.y = this.stage.stageHeight;
			}	
		}	
	}	
}

PongGame.as

package {
	
	import flash.display.MovieClip;
	import flash.events.*;
	
	public class PongGame extends MovieClip {
		
		public function PongGame() {
			this.addEventListener(Event.ENTER_FRAME, update);
			ball.addEventListener("P1_SCORE", player1Score);
			ball.addEventListener("P2_SCORE", player2Score);
		}
		
		private function player1Score(e:Event) {
			trace("Player 1 has scored!!!");
		}
		
		private function player2Score(e:Event) {
			trace("Player 2 has scored!!!");
		}		
		
		private function update(e:Event):void {
			player1.y = this.stage.mouseY;
			
			if(player1.hitTestObject(ball)) {
				ball.impact();
			}
			
			if(player2.hitTestObject(ball))  {
				ball.impact();
			}
			
			if(ball.y < player2.y) {
				player2.y = player2.y - 4.7;
			} else if (ball.y > player2.y) {
				player2.y = player2.y + 4.7;
			}
		}
		
	}
	
}