How to model multiple inheritance objects in Java

Question

i've got the following Problem in a little soccer manager game i'm writing. I've got the classes Person, Player, Coach, Manager. Person is the base Class of the other ones. The Problem is that a Player can also be a Coach and/or a Manager. By adding more Roles (e.g. groundkeeper) i'll get more and more complex - so, how can you implement this efficiently? Isn't there a Pattern for that?

Answer 1

Don't model the role as a type of person. The Person should have a collection of Roles

public enum Role {
  PLAYER,
  COACH,
  REF 
}

public class Player {
  private final String name;
  private Collection<Role> roles = new ArrayList<Role>();

  public Player(String name) {
    this.name = name;
  }

  public void addRole(Role role) {
    this.roles.add(role);
  }
 }

Answer 2

I'd have a Role interface whose implementation classes wrapped a Person as a data member. (AbstractRole makes sense here.)

Prefer composition over inheritance, especially in this case.