1 // 1) 单例： 任意对象都是单例，无须特别处理
2
3 var obj = {name: 'michaelqin', age: 30};
4
5 // 2) 工厂: 就是同样形式参数返回不同的实例
6 function Person() { this.name = 'Person1'; }
7 function Animal() { this.name = 'Animal1'; }
8
9 function Factory() {}
10 Factory.prototype.getInstance = function(className) {
11 return eval('new ' + className + '()');
12 }
13
14 var factory = new Factory();
15 var obj1 = factory.getInstance('Person');
16 var obj2 = factory.getInstance('Animal');
17 console.log(obj1.name); // Person1
18 console.log(obj2.name); // Animal1
19
20 //3) 代理: 就是新建个类调用老类的接口,包一下
21 function Person() { }
22 Person.prototype.sayName = function() { console.log('michaelqin'); }
23 Person.prototype.sayAge = function() { console.log(30); }
24
25 function PersonProxy() {
26 this.person = new Person();
27 var that = this;
28 this.callMethod = function(functionName) {
29 console.log('before proxy:', functionName);
30 that.person[functionName](); // 代理
31 console.log('after proxy:', functionName);
32 }
33 }
34
35 var pp = new PersonProxy();
36 pp.callMethod('sayName'); // 代理调用Person的方法sayName()
37 pp.callMethod('sayAge'); // 代理调用Person的方法sayAge()
38
39 //4) 观察者: 就是事件模式，比如按钮的onclick这样的应用.
40 function Publisher() {
41 this.listeners = [];
42 }
43 Publisher.prototype = {
44 'addListener': function(listener) {
45 this.listeners.push(listener);
46 },
47
48 'removeListener': function(listener) {
49 delete this.listeners[listener];
50 },
51
52 'notify': function(obj) {
53 for(var i = 0; i < this.listeners.length; i++) {
54 var listener = this.listeners[i];
55 if (typeof listener !== 'undefined') {
56 listener.process(obj);
57 }
58 }
59 }
60 }; // 发布者
61
62 function Subscriber() {
63
64 }
65 Subscriber.prototype = {
66 'process': function(obj) {
67 console.log(obj);
68 }
69 }; // 订阅者
70
71 var publisher = new Publisher();
72 publisher.addListener(new Subscriber());
73 publisher.addListener(new Subscriber());
74 publisher.notify({name: 'michaelqin', ageo: 30}); // 发布一个对象到所有订阅者
75 publisher.notify('2 subscribers will both perform process'); // 发布一个字符串到所有订阅者
