/***************************
**** Interface Function ****
***************************/
// Constructor
var Interface = function(name, methods) {
	if (arguments.length != 2) {
		throw new Error('Interface constructor called with ' + arguments.length + ' arguments, but expected exactly 2.');
	}
	
	this.name = name;
	this.methods = [];
	for(i = 0; i < methods.length; i++) {
		if (typeof methods[i] !== 'string') {
			throw new Error('Interface constructor expects method names to be passed in as a string.');
		}
		this.methods.push(methods[i]);
	}
}

// Static class method
Interface.ensureImplements = function(object) {
	if(arguments.length < 2) {
		throw new Error('Function Interface.ensureImplements called with ' + arguments.length + 'arguments, but expected at least 2.');
	}
	
	for(var i = 1, len = arguments.length; i < len; i++) {
		var interface = arguments[i];
		
		if(interface.constructor !== Interface) {
			throw new Error('Function Interface.ensureImplements expects arguments two and above to be instances of Interface.');
		}
		
		for(var j = 0, methodsLen = interface.methods.length; j < methodsLen; j++) {
			var method = interface.methods[j];
			if(!object[method] || typeof object[method] !== 'function') {
				throw new Error('Function Interface.ensureImplements: object does not implement the "' + interface.name + '" interface. Method "' + method + '" was not found.');
			}
		}
	}
}

/************************
**** Extend Function ****
************************/
function extend(subClass, superClass) {
	var F = function() {};
		F.prototype = superClass.prototype;
		
	subClass.prototype = new F();
	subClass.prototype.constructor = subClass;
	
	subClass.superClass = superClass.prototype;
	if (superClass.prototype.constructor == Object.prototype.constructor) {
		superClass.prototype.constructor = superClass;
	}
}


/***********************
**** Clone Function ****
***********************/
function clone(object) {
	function F() {}
	F.prototype = object;
	return new F;
}