普通类模拟枚举类实现

今天学到一种感觉挺神奇的java写法，别的不说上代码

package enumerationTest;public abstract class Size {public final static Size BIG = new Size(){@Overridepublic Size chang() {return SMALL;}};public final static Size SMALL = new Size(){@Overridepublic Size chang() {return BIG;}};public abstract Size chang();public String toString(){return this==BIG?"BIG":"SMALL";}public static void main(String[] args) {Size size = Size.BIG;System.out.println(size.chang());}}