js-一个Demo面向对象高级形态

//语法甘露：
var object =    //定义小写的object基本类，用于实现最基础的方法等
{
    isA: function(aType)   //一个判断类与类之间以及对象与类之间关系的基础方法
    {
        var self = this;
        while(self)
        {
            if (self == aType)
              return true;
            self = self.Type;
        };
        return false;
    }
};
 
function Class(aBaseClass, aClassDefine)    //创建类的函数，用于声明类及继承关系
{
    function class_()   //创建类的临时函数壳
    {
        this.Type = aBaseClass;    //我们给每一个类约定一个Type属性，引用其继承的类
        for(var member in aClassDefine)
            this[member] = aClassDefine[member];    //复制类的全部定义到当前创建的类
    };
    class_.prototype = aBaseClass;
    return new class_();
};
 
function New(aClass, aParams)   //创建对象的函数，用于任意类的对象创建
{
    function new_()     //创建对象的临时函数壳
    {
        this.Type = aClass;    //我们也给每一个对象约定一个Type属性，据此可以访问到对象所属的类
        if (aClass.Create)
          aClass.Create.apply(this, aParams);   //我们约定所有类的构造函数都叫Create，这和DELPHI比较相似
    };
    new_.prototype = aClass;
    return new new_();
};
 
//语法甘露的应用效果：    
var Person = Class(object,      //派生至object基本类
{
    Create: function(name, age)
    {
        this.name = name;
        this.age = age;
    },
    SayHello: function()
    {
        alert("Hello, I'm " + this.name + ", " + this.age + " years old.");
    }
});
 
var Employee = Class(Person,    //派生至Person类，是不是和一般对象语言很相似？
{
    Create: function(name, age, salary)
    {
        Person.Create.call(this, name, age);  //调用基类的构造函数
        this.salary = salary;
    },
    ShowMeTheMoney: function()
    {
        alert(this.name + " $" + this.salary);
    }
});
 
var BillGates = New(Person, ["Bill Gates", 53]);
var SteveJobs = New(Employee, ["Steve Jobs", 53, 1234]);
BillGates.SayHello();
SteveJobs.SayHello();
SteveJobs.ShowMeTheMoney();
 
var LittleBill = New(BillGates.Type, ["Little Bill", 6]);   //根据BillGate的类型创建LittleBill
LittleBill.SayHello();
 
alert(BillGates.isA(Person));       //true
alert(BillGates.isA(Employee));     //false
alert(SteveJobs.isA(Person));       //true
alert(Person.isA(Employee));        //false
alert(Employee.isA(Person));        //true