public Class MailClient{
  String emailServiceProvider;
  String username;
  String password;

  public void initialConfiguration(String emailServiceProvider, String userName, String password){

    this.emailServiceProvider = emailServiceProvider; // value google, yahoo
    this.userName = userName;  // account username
    this.password = password;  // account password
  }

  public void sendEmail(String recipient, String subject, String messageBody ){
    if (this.emailServiceProvider == "google"){

      // dummy gmail low level api
      GMailLowLevelClass gmailLowLevelObject = new GMailLowLevelClass();
      gmailLowLevelObject.connect(this.userName, this.password)
      gmailLowLevelObject.send(receipient, subject, messageBody);
    }
    else (this.emailServiceProvider == "yahoo"){

      // dummy yahoo low level api
      yahooLowLevelClass yahooLowLevelObject = new yahooLowLevelClass();
      yahooLowLevelObject.connect(this.userName, this.password)
      yahooLowLevelObject.send(receipient, subject, messageBody);
    }
  }

  public String receiveEmail(){
    if (this.emailServiceProvider == "google"){

      GMailLowLevelClass gmailLowLevelObject = new GMailLowLevelClass();
      gmailLowLevelObject.connect(this.userName, this.password)
      gmailLowLevelObject.receiveEmail();
    }
    else (this.emailServiceProvider == "yahoo"){

      yahooLowLevelClass yahooLowLevelObject = new yahooLowLevelClass();
      yahooLowLevelObject.connect(this.userName, this.password)
      yahooLowLevelObject.receiveEmail();
    }
  }
}