How to model multiple inheritance objects in Java

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开发者_Go百科 more and more complex - so, how can you implement this efficiently? Isn't there a Pattern for that?

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);
  }
 }

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.

This would be only a proposal.

When I read your question I'm getting an idea that your player may be 'promoted' or 'downgraded' during the game. For instance, a retired player may become a 'coach'.

The second thing (which you've already noticed) is the fact that a single person may be both a coach and a manager.

That's why I would create a collection of Role-s in the Person class.

A Role may could be an abstract class and it may have the following subclasses:

• Player
• Coach
• Manager
• etc.

You can have an enum type for this

enum Role {
   Player, Coach, Manager, GroundsKeeper
}

class Person {
   final Set<Role> roles = EnumSet.noneOf(Role.class);
}

This way a person can have any number of roles.