一个变量存储多个状态

       

 

package mypacket;

public class Stage{

	static int stages = 0;
	/**
	 * 设置状态
	 * @param stage
	 */
	private static void setStage(int stage){
		stages |= stage;
	}
	/**
	 * 判断状态是否存在
	 * @param stage
	 * @return
	 */
	private static boolean isStage(int stage){
		return (stages & stage) != 0;
	}
	/**
	 * 清除状态
	 * @param stage
	 */
	private static void clearStage(int stage){
		stages =  (stages | stage) ^ stage;
	}
	public static void main(String[] args) {
		int stage0 = 1;
		int stage1 = 1 << 1;
		
		System.out.println("before set stage: stage0 is " + (isStage(stage0)? "" :"not ")  + "in the result.");
		System.out.println("before set stage: stage1 is " + (isStage(stage1)? "" :"not ")  + "in the result.");
		setStage(stage0);
		setStage(stage1);
		System.out.println("after set stage: stage0 is " + (isStage(stage0)? "" :"not ")  + "in the result.");
		System.out.println("after set stage: stage1 is " + (isStage(stage1)? "" :"not ")  + "in the result.");
		clearStage(stage0);
		System.out.println("after clear stage :stage0 is " + (isStage(stage0)? "" :"not ")  + "in the result.");
		
	}
}

 这样就可以把多个状态保存在stages这个变量里面了，在实际开发过程中，建议将各个状态以枚举类型存在，在上面的设置，删除和判断的方法里传入的参数也改成枚举类型，防止出错。