接口及继承相关方法

类式继承：

function dw(x) { document.writeln(x + "<br />"); } function extend(subClass, superClass) { var F = function(){}; F.prototype = superClass.prototype; subClass.prototype = new F(); subClass.prototype.constructor = subClass; //superClass属性用来弱化sub,super之间的耦合，可以使用此属性调用超类中的方法 subClass.superClass = superClass.prototype; if (superClass.prototype.constructor == Object.prototype.constructor) { superClass.prototype.constructor = superClass; } } function Person(name) { this.name = name; } Person.prototype.getName = function(){ return this.name; } function Author(name, books) { Author.superClass.constructor.call(this, name); //Person.call(this, name);　//这种方式也可，但将超类名称固化在声明中，增加了耦合 this.books = books; } extend(Author, Person); Author.prototype.getBooks = function(){ return this.books; } Author.prototype.getName = function(){ var name = Author.superClass.getName.call(this); return name + ", Author of " + this.getBooks(); } var a = new Author("tom", "DP"); dw(a.getBooks()); dw(a.getName());

 

 

 

//原型式继承 function clone(object){ function F(){}; F.prototype = object; return new F; } //混元类 function augment(receivingClass, givingClass){ if(arguments[2]){ for(var i=2; i<arguments.length; i++){ receivingClass.prototype[arguments[i]] = givingClass.prototype[arguments[i]]; } } else{ for(methodName in givingClass.prototype){ if(!receivingClass.prototype[methodName]){ receivingClass.prototype[methodName] = givingClass.prototype[methodName]; } } } }

 

接口：

var Interface = function(name, methods){ if(arguments.length != 2){ throw new Error("Interface constructor called with " + arguments.length + "arguments,but expected exactly 2."); } this.name = name; this.methods = []; for(var i=0; i<methods.length; i++){ if(typeof methods[i] !== "string"){ throw new Error("interface need the method name as a string."); } this.methods.push(methods[i]); } } Interface.ensureImplements = function(object){ if(arguments.length < 2){ throw new Error("Function Interface.ensureImplements called with" + arguments.length + " arguments,but expected at least 2.") } for(var i=1; i<arguments.length; i++){ var interfaceElem = arguments[i]; if(interfaceElem.constructor !== Interface){ throw new Error(""); } for(var j=0; j<interfaceElem.methods.length; j++){ var method = interfaceElem.methods[j]; if(!object[method] || typeof object[method] !== 'function'){ throw new Error(method + " was not found") } } } } //test code var Com = new Interface("Com",['add','remove','save']); var createT = function(){ //this.add = function(){}; this.remove = function(){}; //this.save = function(){}; } var t1 = new createT(); Interface.ensureImplements(t1,Com);

 

继承：