1 <html>
2 <head>
3 <title>javascript高级语法20-责任链模式</title>
4 </head>
5 <body>
6 <script>
7 /*责任链模式
8 * 消除发送者与接收者之间的耦合。
9 * 1.责任链的发送者知道链的入口是谁
10 * 2.每一个链节点知道自己的下一个节点是谁
11 * 3.每一个链的传入和传出值是一样的；
12 */
13
14 //扩展filter函数
15 Function.prototype.method = function(name,fn){
16 this.prototype[name] = fn;
17 return this;
18 }
19 if(!Array.prototype.filter){
20 Array.method("filter",function(fn,obj){
21 var scope = this.Obj || window;
22 var a = [];
23 for(var i=0;i<this.length;i++){
24 if(!fn.call(scope,this[i],i,this)){
25 continue;
26 }
27 a.push(this[i]);
28 }
29 //返回过滤好的数据
30 return a;
31 })
32 }
33
34 function demo(){
35 //扩展window
36 window.setSuccessor = function(after,before){
37 after.successor = before;
38 }
39 //用于拷贝字符串的方法 20*"-" = "------------------"
40 window.copyStr = function(num,str){
41 var newStr = '';
42 for(var i=0;i<num;i++){
43 newStr += str;
44 }
45 return newStr;
46 }
47 //转换数组中的对象为字符串
48 var showStr = function(arr){
49 var newStr = "";
50 for(var i=0;i<arr.length;i++){
51 newStr += JSON.stringify(arr[i]);
52 }
53 return newStr;
54 }
55
56 //书店找书和加书两个需求
57 //用户可以输入关键字找书（书号，作者，名称）
58 //不同书架管理员管理自己的书籍添加任务
59
60 //图书类
61 var Book = function(id,name,author,type){
62 this.id = id;
63 this.name = name;
64 this.author = author;
65 this.type = type;
66 }
67 //书店
68 var myBookShop = (function(){
69 //书架
70 var jsBooks = new Array(); //JS书架
71 var cBooks = new Array(); //C语言书架
72 var pythonBooks = new Array(); //python书架
73 //内部类1
74 function addJSBook(book){
75 if(book.type == "js"){
76 jsBooks.push(book);
77 }else{
78 //负责传递到下一个功能
79 addJSBook.successor(book);
80 }
81 }
82 //内部类2
83 function addPythonBook(book){
84 if(book.type == "py"){
85 pythonBooks.push(book);
86 }else{
87 //负责传递到下一个功能
88 addPythonBook.successor(book);
89 }
90 }
91 //内部类3
92 function addCBook(book){
93 if(book.type == "c"){
94 cBooks.push(book);
95 }else{
96 //负责传递到下一个功能
97 addCBook.successor(book);
98 }
99 }
100 //设置责任链
101 setSuccessor(addJSBook,addPythonBook);
102 setSuccessor(addPythonBook,addCBook);
103
104 //查询书籍
105 var bookList = null;
106 function findBookById(keyword){
107 if(!bookList){
108 bookList = jsBooks.concat(cBooks).concat(pythonBooks);
109 }
110 var book = new Array();
111 book = bookList.filter(function(book){
112 if(book.id.indexOf(keyword) != -1){
113 return true;
114 }else{
115 return false;
116 }
117 });
118 //进行链式查询
119 return book.concat(findBookById.successor(keyword,book));
120 }
121 function findBookByName(keyword,book){
122 book = bookList.filter(function(book){
123 if(book.name.indexOf(keyword) != -1){
124 return true;
125 }else{
126 return false;
127 }
128 });
129 return book;
130 }
131 //规划责任链
132 setSuccessor(findBookById,findBookByName);
133
134 //真正的图书馆类
135 return function(){
136 this.addBook = function(book){
137 if(book instanceof Book){
138 //因为我知道谁是链的入口。可以这么写
139 addJSBook(book);
140 }
141 }
142 this.findBook = function(keyword){
143 return findBookById(keyword);
144 }
145 this.showBooks = function(){
146 //document.write("c语言类图书"+cBooks.toSource()+"<br>")
147 //这里的toSource()方法只有火狐支持,所以我全局定义了showStr方法
148 document.write("js类图书"+showStr(jsBooks)+"<br>")
149 document.write("c语言类图书"+showStr(cBooks)+"<br>")
150 document.write("Python类图书"+showStr(pythonBooks)+"<br>")
151 document.write(copyStr(60,"-")+"<br>");
152 }
153 }
154 })();
155 //添加book
156 var pb = new myBookShop();
157 pb.addBook(new Book("00101","Extjs","zhangsan","js"));
158 pb.addBook(new Book("00102","cprimer","jim","js"));
159 pb.addBook(new Book("00103","c#","chance","c"));
160 pb.addBook(new Book("00201","c++","chance","c"));
161 pb.addBook(new Book("00202","python","py","py"));
162 pb.addBook(new Book("00203","py实战","杨国正","py"));
163 //展示
164 pb.showBooks();
165 //查询
166 document.write(showStr(pb.findBook("02"))+"<br>");
167 document.write(copyStr(60,"-")+"<br>");
168 document.write(showStr(pb.findBook("c")));
169 }
170 demo();
171 </script>
172 </body>
173 </html>
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