Object-Oriented-Programming | used C # to make all programs , You can run

public abstract class Unit {

  private final Unit[] children;

  public Unit(Unit... children) {
    this.children = children;
  }

  public void accept(UnitVisitor visitor) {
    Arrays.stream(children).forEach(child -> child.accept(visitor));
   

@Slf4j
public class Wizard {

  private final Deque undoStack = new LinkedList<>();
  private final Deque redoStack = new LinkedList<>();

  public Wizard() {}

  public void castSpell(Runnable runnable) {
    runnable.run();
    undoStac  

public interface PartyMember {

  void joinedParty(Party party);

  void partyAction(Action action);

  void act(Action action);
}

@Slf4j
public abstract class PartyMemberBase implements PartyMember {

  protected Party party;

  @Override
  public