import java.util.ArrayList;
import java.util.List;
public class ChatMediatorImpl implements ChatMediator {
private List<User> users;
  public ChatMediatorImpl(){
  this.users=new ArrayList<>();
  }
  @Override
  public void addUser(User user){
  this.users.add(user);
  }
  @Override
  public void sendMessage(String msg, User user) {
	for(User u : this.users){
	//message should not be received by the user sending it
		if(u != user){
		u.receive(msg);
		}
	}
  }
}