// The base class for the different types of items the List can contain

abstract class ListItem {}

class TouchData implements ListItem {
  int event;
  int fingerNumber;
  int x;
  int y;

  TouchData(this.event, this.fingerNumber, this.x, this.y);

  void touchEvent(int E, int X, int Y) {
    this.event = E;
    this.x = X;
    this.y = Y;
  }
}