galaxy/static/scripts/class.js

/*!
 *  Class definition
 *
 *  Copyright (c) 2008 John Resig (http://ejohn.org/blog/simple-javascript-inheritance/)
 *  Inspired by base2 and Prototype
 */

"use strict";

(function () {

    var initializing = false, 
    
        fnTest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;
    
    // The base Class implementation (does nothing) 
    this.Class = function(){};
        
    // Create a new Class that inherits from this class
    Class.extend = function (prop)
    {
        var _super = this.prototype;
        
        // Instantiate a base class (but only create the instance, don't run the init constructor)
        initializing = true;
        
        var prototype = new this();
        
        initializing = false;
        
        // Copy the properties over onto the new prototype
        for (var name in prop) 
        {
        
            // Check if we're overwriting an existing function
            prototype[name] = (typeof prop[name] === "function" && typeof _super[name] === "function" && fnTest.test(prop[name]) ?
            
                (function(name, fn)
                {
                    return function()
                    {
                        var tmp = this._super;
        
                        // Add a new ._super() method that is the same method
                        // but on the super-class
                        this._super = _super[name];
                        
                        // The method only need to be bound temporarily, so we
                        // remove it when we're done executing
                        var ret = fn.apply(this, arguments);        
                        this._super = tmp;
                        
                        return ret;
                    };
                }(name, prop[name])) : prop[name]);
        }

        // The dummy class constructor
        function Class()
        {
            // All construction is actually done in the init method
            if (!initializing && this.init)
            {
                this.init.apply(this, arguments);
            }
        }
        
        // Populate our constructed prototype object
        Class.prototype = prototype;
        
        // Enforce the constructor to be what we expect
        Class.constructor = Class;
        
        // And make this class extendable
        Class.extend = arguments.callee;
        
        return Class;
    };
    
}());