多例设计模式

//限制实例化对象的个数 多个
class Sex {
	private String title;
	//类内部定义有限个个公共实例化对象，只能通过static方法返回有限对象
	private static final Sex MALE = new Sex("男");
	private static final Sex FEMALE = new Sex("女");
	private Sex(String title) {
		this.title = title;
	}//构造对象私有化，外界不会随便产生新对象
	public String toString() {
		return this.title;
	}
	public static Sex getInstance(int c) {
		switch(c) {
			case 1 :
				return MALE;
			case 2 :
				return FEMALE;
			default :
				return null;
		}
	}
}
public class TestDemo {
	public static void main(String args[]) {
		Sex s = Sex.getInstance(2);
		System.out.println(s);
	}
}