java - How to avoid type-checking of a subclass? -

i have code:

public abstract class character {     public abstract void attack(character victim);     public abstract void receiveattack(attack attack); }  public class charactera extends character {     public void attack(character victim) {         if (victim.getclass().equals(this.getclass())             return;          victim.receiveattack(new attack(base_dmg));     } } 

the idea character can attack , receiveattacks to/from other characters, cannot receive attack comes character of own class (charactera cannot attack charactera attack characterb or receive attack characterb).

i know checking type of object bad smell , caused because of bad design, question how change design don't have check object type?

edit

the class not named character, name simplify example.

there no teams. charactera can attack other character not charactera.

final edit

thanks everyone, solved using visitor pattern.

a simple solution/ work-around have 1 class, , every character object has string field named characterteam or of like. characters on team, set field "a" or "ateam". b team, set field "b" or "bteam". compare characterteam strings in attack method.

also, advise against having class named character might interfere wrapper class char, named character.