public class Client {
  public static void main(String[] args) {
    Composite root = new Composite("root");
    root.add(new Leaf("1"));
    root.add(new Leaf("2"));

    Composite compA = new Composite("compA");
    compA.add(new Leaf("A1"));
    compA.add(new Leaf("A2"));
    root.add(compA);

    Composite compB = new Composite("compB");
    compB.add(new Leaf("B1"));
    compB.add(new Leaf("B2"));
    compB.add(new Leaf("B3"));
    root.add(compB);

    root.display();
  }
}