public Class MailConfiguration{

  public static String userName;
  public static String password;
  public static String emailService;
}

public Class MailInit{

  public void initialConfiguration(String userName, String password, String emailService ){
    MailConfiguration.userName = userName;
    MailConfiguration.password = password;
    MailConfiguration.emailService = emailService;
  }
}

public Class Mail{

  public void sendEmail(String recipient, String subject, String messageBody){

    if (MailConfiguration.emailServiceProvider == "google"){
      GMailLowLevelClass gmailLowLevelObject = new GMailLowLevelClass();
      gmailLowLevelObject.connect(MailConfiguration.userName, MailConfiguration.password)
      gmailLowLevelObject.send(receipient, subject, messageBody);
    }

    else (MailConfiguration.emailServiceProvider == "yahoo"){
      yahooLowLevelClass yahooLowLevelObject = new yahooLowLevelClass();
      yahooLowLevelObject.connect(MailConfiguration.userName, MailConfiguration.password)
      yahooLowLevelObject.send(receipient, subject, messageBody);
    }
}