/*
 reader common
*/

var Queue = Class.create();
Queue.extend({
	initialize: function(){ this.queue = [] },
	step : 1,
	interval : 100,
	push: function(f){
		this.queue.push(f);
	},
	exec: function(){
		var queue = this.queue;
		var step = this.step;
		var interval = this.interval;
		(function(){
			var self = arguments.callee;
			var count = 0;
			while(count < step){
				var f = queue.shift();
				isFunction(f) && f();
				count++;
			}
			if(queue.length){
				self.later(interval)()
			}
		}).later(interval)();
	}
});