索引 意图 结构 参与者 适用性 效果 相关模式 实现 实现方式(一):Null Object 的示例实现. 意图 通过对缺失对象的封装,以提供默认无任何行为的对象替代品. Encapsulate the absence of an object by providing a substitutable alternative that offers suitable default do nothing behavior. In short, a design where "nothing w
空对象模式:用一个空对象来取代null实例的检查,空对象实现一个不做任何动作的关系.(消除如if(Object == null) 这样的检查null实例代码) 例子: public abstract class Duck { public String name; public abstract void getName(); } public class ConcreteDuck extends Duck { public ConcreteDuck(String name) { this.na
We will learn how to change the address bar using a component from React Router. In Root.js: We need to add a param to change the Route: import React from 'react'; import {Provider} from 'react-redux'; import {Router, Route, browserHistory } from 're
jquery中有一个函数isEmptyObject()用来判断制定参数是否是一个空对象. 示例如下: function isEmptyObject(e) { var t; for (t in e) return !1; return !0 } var m = {'a':'111','b':'222'}; var n = {}; console.log(isEmptyObject(m)); //false console.log(isEmptyObject(n)); //true