Class Admin

package group_project;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Scanner;

public class Admin {
	public int ID, age, roomNum, balance;
	public String firstName, lastName, gender, identityCard, userName, password, roomType;
	public String checkInTime, checkOutTime, service, loggedIn;
	Scanner input = new Scanner(System.in);
	ArrayList<String> list = new ArrayList<>();



	public Admin() {

	}


	/* @author Jasmin Bektic
	 *
	 * Method confirms connection */
	public Connection getConnection() {
		try {
			String driver = "com.mysql.jdbc.Driver";
			String url = "jdbc:mysql://localhost:3306/hotel";
			String user = "root";
			String pass = "";
			Class.forName(driver);

			//Connecting with provided url,userName and pass
			Connection con = DriverManager.getConnection(url, user, pass);
			return con;
		} catch (Exception e) {		//Catch errors
			System.out.println(e);
		}
		return null;
	}

	public void checkGuest() {

	}

	public void enterInfo() throws SQLException {
		firstName = "John";
		lastName = "Snow";
		gender = "m";
		identityCard = "123456";
		age = 29;
		roomNum = checkAvailableRoom();
		roomType = roomType();
		checkInTime = "14:05";
		userName = checkAvailableUserName();
		password = "123456";

			Connection con = getConnection();
			String sql = "INSERT INTO information (FirstName, LastName, Gender, IdentityCard, Age, RoomNumber, RoomType, CheckInTime, UserName, Password) VALUES ('"+firstName+"', '"+lastName+"', '"+gender+"', '"+identityCard+"', "+age+", "+roomNum+",'"+roomType+"','"+checkInTime+"','"+userName+"','"+password+"')";
			PreparedStatement statement = con.prepareStatement(sql);

			statement.executeUpdate();
	}

	/* @author Davor Sadikovic
	 *
	 * Method for checking available rooms */
	public int checkAvailableRoom() throws SQLException {
		Statement s = getConnection().createStatement();
		s.executeQuery("SELECT RoomNumber FROM information");
		ResultSet rs = s.getResultSet();
		System.out.print("Occupied room numbers: ");

		//Listing occupied rooms
		while (rs.next()) {
			int room = rs.getInt("RoomNumber");
		    System.out.print(room + " ");
		}
		System.out.println();
		rs.close ();
		s.close ();

		//Assign room number for a guest
		System.out.println("Enter room number for a guest:");
		int num = input.nextInt();
		return num;
	}

	/* @author Jasmin Bektic
	 *
	 * Assign room type for guest */
	public String roomType() {
		System.out.println("\nChoose option:\n1- Single Room\n2- Double Room\n3- Apartment");
		int option = input.nextInt();
		String s = "";
		switch (option) {
			case 1: s = "Single Room"; break;
			case 2: s = "Double Room"; break;
			case 3: s = "Apartment"; break;
		}
		return s;
	}

	/* @author Jasmin Bektic
	 *
	 * Method checking available user name */
	public String checkAvailableUserName() throws SQLException {
		ArrayList<String> li = new ArrayList<>();
		Statement s = getConnection().createStatement ();
		s.executeQuery("SELECT UserName FROM information");
		ResultSet rs = s.getResultSet();
		System.out.println("Assign username:");
		String user = input.next();

		//Transfering user names from database to array
		while (rs.next()) {
			String str = rs.getString("UserName");
			li.add(str);
		}
		rs.close ();
		s.close ();

		//Compare user name to names from array
		for (int i = 0; i < li.size(); i++) {
			if (user.equals(li.get(i))) {
		    	System.out.println("User name already exist, try another one:");
		    	user = input.next();
		    	i = 0;
			}
		}
		return user;
	}

	/* @author Maja Vasilic
     *
	 * providing information from database based on entry */
	public void searchDatabase(String s) throws Exception {
		try {
			// estalish connection to the database invoking method
			Connection con = getConnection();
			// var query with SQL query
			String query = "SELECT * FROM hotel.information WHERE FirstName = ? OR IdentityCard= ? OR UserName = ?";
			// create statement
			PreparedStatement statement = con.prepareStatement(query);

			// actual values are set to parameters
			statement.setString(1, s);
			statement.setString(2, s);
			statement.setString(3, s);
			//query execution
			ResultSet result = statement.executeQuery();

			ResultSetMetaData rsmd = result.getMetaData();
			int columnCount = rsmd.getColumnCount();

			String format = "%-20s";

			// print column names
			for (int i = 1; i <= columnCount; i++) {
				System.out.printf(format, rsmd.getColumnLabel(i));
			}
			System.out.println();

			// print underline
			for (int i = 1; i <= columnCount * 20; i++) {
				System.out.print("_");
			}
			System.out.println();

			// print information from database
			while (result.next()) {
				for (int i = 1; i <= columnCount; i++) {
					System.out.printf(format, result.getString(i));
				}
				System.out.println();
			}
		} catch (Exception e) {
			System.out.println(e);
		}
	}

	//nedovrsena metoda
	public void checkOnlineStatus() {
		System.out.println(list);
		System.out.println("No\tUserName");
		System.out.println("------------------");
		for (int i = 1; i <= list.size(); i++) {
			System.out.print(i + "\t" + list.get(i - 1));
		}
	}
}