承接上篇原型真谛一,下面是个更丰富的示例:
<script type="text/javascript">
var object = // 定义小写的object基本类,用于实现最基础的方法
{
isA: function(aType) // 用于判断类间及对象与类间关系的基础方法
{
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; // 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); // 约定所有类的构造函数都叫Create
};
new_.prototype = aClass;
return new new_();
};
// 应用效果
var Person = Class(object, // 派生自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, // 派生自Person类
{
Create: function(name, age, salary)
{
Person.Create.call(this, name, age); // 调用基类的构造函数
this.salary = salary;
},
ShowSalary: function()
{
alert(this.name + " $ " + this.salary);
}
});
var Bill = New(Person, ["Bill", 30]);
var Steve = New(Employee, ["Steve", 28, 5000]);
Bill.SayHello();
Steve.SayHello();
Steve.ShowSalary();
var LittleBill = New(Bill.Type, ["LittleBill", 6]);
LittleBill.SayHello();
alert(Bill.isA(Person)); // true
alert(Bill.isA(Employee)); // false
alert(Steve.isA(Person)); // true
alert(Person.isA(Employee)); // false
alert(Employee.isA(Person)); // true
</script>