class ComponentType {
 static var _nextBit = 1;
 static var _nextId = 0;

 var _bit = 0;
 var _id = 0;

 ComponentType() {
   _bit = _nextBit;
   _nextBit = _nextBit << 1;
   _id = _nextId++;
 }

 int get bit => _bit;
 int get id => _id;
}