1. Bean @Entity @Table(name = "entities") public class Entities { public enum entityType { location, group; } private entityType locationOrGroup; @Column(name="location_or_group") @Enumerated(EnumType.STRING) //Should set the type of l…
Principle When implement the singleton pattern please decorate the INSTANCE field with "static final" and decorate the constructor with "private". // Singleton with static factory public class Elvis { private static final Elvis INSTANC…
原文网址:http://iaiai.iteye.com/blog/1843553 1 背景 在java语言中还没有引入枚举类型之前,表示枚举类型的常用模式是声明一组具有int常量.之前我们通常利用public final static 方法定义的代码如下,分别用1 表示春天,2表示夏天,3表示秋天,4表示冬天. public class Season { public static final int SPRING = 1; public static final int SUMMER = …
Item3:Enforce the singleton property with a private constructor or an enum type 采用枚举类型(ENUM)实现单例模式. public enum Elvis { INSTANCE; public void leaveTheBuiding(){ System.out.println("a single-element enum type is the best way to implement a singleton&q…
1. 通过一个公开的字段来获取单例 // Singleton with public final field public class Elvis { public static final Elvis INSTANCE = new Elvis(); private Elvis() { ... } public void leaveTheBuilding() { ... } } The main advantage of the public field approach is that th…