Staff.java

/*
This class facilitates the communication between the model and the mysql database, for staff purposes.
*/

package com.example.schedulerapp;

import java.sql.*;

public class Staff {

    // Object that facilitates the connection to the database
    private final Connection dbConnection;

    /*
    Name: Staff Constructor
    Parameters: None
    Description: Establishes connections to the local database. If running on a different computer
    make sure that the port number (replace '3306'), database name (replace 'ScheduleApp'), user, and password are
    set correctly.
    Return: Staff Object
     */
    protected Staff(Connection c) {
        this.dbConnection = c;
    }

    /*
    Name: addEmployee
    Parameters:
        String firstName: First name of the employee,
        String lastName: Last name of the employee .
    Description: Adds an employee by querying the database. Also, assigns a unique ID.
    Return:
        String newEmployee: If the employee was added successfully, then it returns their new details, else returns an empty string.
     */
    protected String addEmployee(String firstName, String lastName){
        String newEmployee = "";
        try {
            Statement myStatement = dbConnection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
            myStatement.executeUpdate("insert into Employees (first_name,last_name) values ('" + firstName + "', '" + lastName + "')");
            ResultSet myRs = myStatement.executeQuery("select * from Employees where first_name='Rafi' and last_name='Zereselasie'");
            if (myRs.last()) {
                newEmployee = myRs.getString("employee_ID") + "." + myRs.getString("first_name") + "." + myRs.getString("last_name");
            }
        } catch (Exception exception) {
            exception.printStackTrace();
            return newEmployee;
        }
        System.out.println("Employee Added");
        return newEmployee;
    }


    /*
    Name: removeEmployee
    Parameters:
        int ID: The employees unique ID.
    Description: Removes the employee with the same ID by querying the database.
    Return: none
     */
    protected int removeEmployee(int ID){
        try {
            Statement myStatement = dbConnection.createStatement();
            myStatement.executeUpdate("DELETE FROM shifts WHERE (employee_ID =" + ID + ")");
            myStatement.executeUpdate("delete from Employees where employee_id = " + ID);
        } catch (Exception exception) {
            exception.printStackTrace();
            return -1;
        }
        System.out.println("Employee Removed");
        return ID;
    }

    /*
    Name: printEmployees
    Parameters: none
    Description: prints the id, and names of each employee
    Return: none
     */
    protected String getEmployees(){
        StringBuilder response = new StringBuilder("allEmployees");
        try {
            Statement myStatement = dbConnection.createStatement();
            ResultSet myRs = myStatement.executeQuery("select * from Employees");
            while (myRs.next()) {
                response.append("/").append(myRs.getString("employee_ID")).append(".").append(myRs.getString("first_name")).append(".").append(myRs.getString("last_name"));
            }
        } catch (Exception exception) {
            exception.printStackTrace();
            return "Error retrieving employees from database";
        }
        return response.toString();
    }

}