javascript的类继承机制

蓝色_冰点 2014-06-16 06:27:40

自己写的，一直在用着，无不良反应，晒出来玩玩哈。。。

<html>

<head>

    <title></title>

    <script type="text/javascript">

(function(){

    function callBase() {

        var baseName = arguments[0];

        var args = [];

        for (var i = 1; i < arguments.length; i++) {

            args.push(arguments[i]);

        }

        if (!this.__callStack) {

            this.__callStack = {};

        }

        if (!this.__callStack[baseName]) {

            this.__callStack[baseName] = [];

        }

        var fun = null;

        var cs = this.__callStack[baseName];

        if (cs.length == 0) {

            fun = this[baseName].base;

        }

        else {

            fun = cs[cs.length - 1].base;

        }

        cs.push(fun);



        var rv = null;

        try {

            rv = fun.apply(this, args);

        }

        catch (err) {

            cs.length = 0;

            throw err;

        }

        cs.pop();

        return rv;

    }

    var _id = 0;

    function clsID() {

        _id++;

        return "c" + _id;

    }

    var clsMap = {};

    Function._class = clsID();

    Function.prototype.extend = function (baseCls, proto) {

        var F = function () { };

        F.prototype = baseCls.prototype;

        this.prototype = new F();

        for (var member in proto) {

            var oldFun = this.prototype[member];

            var newFun = proto[member];

            if (oldFun) {

                newFun.base = oldFun;

            }

            this.prototype[member] = newFun;

        }

        this.prototype.callBase = callBase;

        var clsKey = baseCls._class + "/" + clsID();

        this._class = clsKey;

        this.prototype.constructor = this;

        clsMap[clsKey] = this;

    };

    Function.prototype._class = "cls_native";

})();

    </script>

</head>

<body>

    <script type="text/javascript">

        /**

        父类定义

        */

        function ClassA(){

            this.name="My name is ClassA";

        }

        ClassA.prototype.show=function(){ alert(this.name) };

        

        function ClassB(){

            //调用父类构造函数

            ClassA.call(this);

            this.name=this.name+"(extend)";

        }

        //继承自ClassA

        //子类.extend(父类,{ ... /* 子类扩展的方法..*/  });

        ClassB.extend(ClassA,

            {

                //覆盖父类的show函数

                show:function(){

                    this.callBase("show"); //可以调用父类的方法

                    alert("再alert一下："+this.name);

                }

            }

        )

        

        var a=new ClassA();

        a.show();

        

        var b=new ClassB();

        b.show();

        

    </script>

</body>

</html>