 		{
 			if (!(stream._usage & StreamUsage.WRITE))
 				throw new Error(
-					'Unable to write in vertex stream: stream usage '
-					+ 'is not set to StreamUsage.WRITE.'
+					'Unable to write in vertex stream: stream usage is not set to StreamUsage.WRITE.'
 				);
 		}
 		
-		public static function dummyData(size : uint, offset : uint = 0) : Vector.<uint>
+		public static function dummyData(size 	: uint,
+										 offset : uint = 0) : Vector.<uint>
 		{
 			var indices : Vector.<uint> = new Vector.<uint>(size);
 			

		minko_stream function invalidate() : void
		{
			_length = _data.length;
			_changed.execute(this);
		}

		private function initialize(indices : Vector.<uint>,

			_resource.dispose();
		}
		
		public function lock() : Vector.<uint>
		{
			checkReadUsage(this);
			checkWriteUsage(this);
			
			_hasChanged = false;
			_locked = true;
			
			return _data;
		}
		
		public function unlock(hasChanged : Boolean = true) : void
		{
			if (_hasChanged && hasChanged)
				_changed.execute(this);
			
			_hasChanged = false;
		}
		
		private static function checkReadUsage(stream : IndexStream) : void
		{
			if (!(stream._usage & StreamUsage.READ))
				throw new Error(
					'Unable to read from vertex stream: stream usage is not set to StreamUsage.READ.'
				);
		}
		
