code: public boolean check(Object credentials)
      {
  	if (this == credentials)
  	    return true;
  	
          if (credentials instanceof Password)
              return credentials.equals(_pw);
          
          if (credentials instanceof String)
              return credentials.equals(_pw);
          
          if (credentials instanceof Credential)
              return ((Credential)credentials).check(_pw);
              
          return false;
      }
docs: /* ------------------------------------------------------------