public synchronized void initEnemies(int size){
		int x = 0 ; // < 800
		int y = 0 ; // < 200
		
		Enemy enemy = null ;
		Thread thread = null ;
		
		if( size == 1){
			
		}else{
			
		}
		
		for( int i = 0; i<size; i++){ //系统每次初始化size个坦克
			
			if( size == 1){
				x = (int)(Math.random() * 700 );
				y = (int)(Math.random() * 50 );
			}else{
				if( i % 3 == 0 ){
					x = 0 + i * 30 ; 
					y = 0 + i * 30 ;
				}else if( i % 3 == 1){
					x = 200 + i * 30; 
					y = 10  + i * 30; 
				}else if( i % 3 == 2 ){
					x = 400 + i * 30; 
					y = 10  + i * 30;
				}
			}
			
			
			enemy = StaticCreateFactory.newTank(x , y ,  (int)(Math.random() * 100 % 4), Tank.ENEMY, this.mainFrame.mapArray);
			thread = new Thread(enemy);
			thread.start();
			enemy.setMainFrame(this.mainFrame);
			this.enemyList.add(enemy);
		}
	}