JavaScript设计模式之责任链模式实例分析

//定义一个静态方法来实现接口与实现类的直接检验//静态方法不要写出Interface.prototype ,因为这是写到接口的原型链上的//我们要把静态的函数直接写到类层次上//定义一个接口类var Interface=function (name,methods) {//name：接口名字  if(arguments.length<2){    alert("必须是两个参数")  }  this.name=name;  this.methods=[];//定义一个空数组装载函数名  for(var i=0;i<methods.length;i++){    if(typeof methods[i]!="string"){      alert("函数名必须是字符串类型");    }else {      this.methods.push( methods[i]);    }  }};Interface.ensureImplement=function (object) {  if(arguments.length<2){    throw new Error("参数必须不少于2个")    return false;  }  for(var i=1;i<arguments.length;i++){    var inter=arguments[i];    //如果是接口就必须是Interface类型    if(inter.constructor!=Interface){      throw new Error("如果是接口类的话，就必须是Interface类型");    }    //判断接口中的方法是否全部实现    //遍历函数集合分析    for(var j=0;j<inter.methods.length;j++){      var method=inter.methods[j];//接口中所有函数      //object[method]传入的函数      //最终是判断传入的函数是否与接口中所用函数匹配      if(!object[method]||typeof object[method]!="function" ){//实现类中必须有方法名字与接口中所用方法名相同        throw new Error("实现类中没有完全实现接口中的所有方法")      }    }  }}

var bookShop=new Interface("bookShop",["addBook","findBook","showBooks"]);//书店接口

var Book=function (bNm,bName,bAuthor,bType) {  this.bNm=bNm;  this.bName=bName;  this.bAuthor=bAuthor;  this.bType=bType;}

var pcatBookShop=(function(){ //书架  var jsBooks = new Array();//js书架  var cBooks = new Array();//c书架  var javaBooks = new Array();//java书架   //内部类1  function AddJsBooks(book) {    if(book.bType=="Js"){      jsBooks.push(book);    }else {      AddJsBooks.successor(book);    }  }  //内部类2  function AddJavaBooks(book) {    if(book.bType=="Java"){      javaBooks.push(book);    }else {      AddJavaBooks.successor(book);    }  }  //内部类3  function AddCBooks(book) {    if(book.bType=="C"){      cBooks.push(book);    }else {      AddCBooks.successor(book);    }  }})()

//扩展window属性window.setSuccessor=function (after,before) {  after.successor=before;//引用的执行}

//设置责任链-----串起来setSuccessor(AddJsBooks,AddJavaBooks);setSuccessor(AddJavaBooks,AddCBooks);

/**********查询书籍************/  var bookList = null;  function FindBbn(keyword) {    //链的头部来初始化参数    if(!bookList){      bookList=jsBooks.concat(cBooks).concat(javaBooks);      var book = new Array();      book=bookList.filter(function (book) {//对booklist进行过滤，过滤的条件为匿名函数        if(book.bName.indexOf(keyword)!=-1){             return true;        }else {          return false;        }      });      //我要进行链式查询      return book.concat(FindBbn.successor(keyword));    }  };  function FindByName(keyword,book){    var book = book;    book = bookList.filter(function(book){      if(book.bName.indexOf(keyword) != -1){        return true;      }else{        return false;      }    });    return book;  }

Function.prototype.method=function (name,fn) {  this.prototype[name]=fn;  return this;}if(!Array.prototype.filter){  Array.method("filter",function (fn,thisObj) {    var scope=thisObj||window;    var a=[];    for(var i=0;i<this.length;i++){      if(!fn.call(scope,this[i],i,this));{        continue;      }      a.push(this[i]);    }    //返回过滤好数据    return a;  })}

setSuccessor(FindBbn,FindByName);

 return function () {    this.addBook=function (book) {      if(book instanceof Book){        AddJsBooks(book);//因为我知道谁是链的入口      }    };    this.findBook=function (keyword) {      return FindBbn(keyword);//游泳规划的责任链可以从头到尾的查询若，FindBbn没有则到FindByName中查询    }    this.showBooks=function () {      document.write("JS类图书"+jsBooks.toSource()+"<br>");      document.write("Java类图书"+javaBooks.toSource()+"<br>");      document.write("C类图书"+cBooks.toSource()+"<br>");      //自动生产----------      document.write(cpoyStr(60,"-")+"<br>");    }  }

//扩展一个可以自动生产-----的方法window.cpoyStr=function (num,str) {  var newStr="";  for(var i=0;i<num;i++){   newStr+=str;  }  return newStr;};

var pb = new pcatBookShop();pb.addBook(new Book("00101","JAVA","JIM","JAVA"));pb.addBook(new Book("00201","C#","world","C"));pb.addBook(new Book("00202","C++/C","Hello","C"));pb.addBook(new Book("00301","JAVASCRIPT","Good","JS"));

//展示pb.showBooks();document.write(pb.findBook("C").toSource())