对象池

package  
{ 
    import flash.display.Sprite; 
     
    public final class SpritePool 
    { 
        //定义对象池的最大尺寸
        private static var MAX_VALUE:uint;
        //对象池增长补偿   不能缺一个 就补一个吧 
        private static var GROWTH_VALUE:uint;
        //当前对象池里空闲可用的对象数目
        private static var counter:uint; 
        //对象池
        private static var pool:Vector.<Sprite>; 
        private static var currentSprite:Sprite; 
          //初始化对象池   存取满对象
        public static function initialize( maxPoolSize:uint, growthValue:uint ):void 
        { 
            MAX_VALUE = maxPoolSize; 
            GROWTH_VALUE = growthValue; 
            counter = maxPoolSize; 
             
            var i:uint = maxPoolSize; 
             
            pool = new Vector.<Sprite>(MAX_VALUE); 
            while( --i > -1 ) 
                pool[i] = new Sprite(); 
        } 
         
        public static function getSprite():Sprite 
        { 
            if ( counter > 0 ) 
                return currentSprite = pool[--counter]; 
            //如果对象池存量不够了 则再续      GROWTH_VALUE 个新对象补充
            var i:uint = GROWTH_VALUE; 
            while( --i > -1 ) 
                    pool.unshift ( new Sprite() ); 
            counter = GROWTH_VALUE; 
            return getSprite(); 
             
        } 
  
        public static function disposeSprite(disposedSprite:Sprite):void 
        { 
            pool[counter++] = disposedSprite; 
        } 
    } 
}