public boolean isValid(){
  return (host != null) && (user != null) && (password != null)&& !host.equals("")&& !user.equals("")&& !password.equals("");
}

public boolean isValid ( ) { return ( host != null ) && ( user != null ) && ( password != null ) && ! host . equals ( "" ) && ! user . equals ( "" ) && ! password . equals ( "" ) ; }
checks whether all required attributes are defined
