Оценка кода

[Lokki1723]

Добрый день

Мне тут задали некоторое небольшое задание сделать.
Почти сделел только остались тесты.

Но мне нужен взгляд со стороны. Мне кажется что сделоно неплохо но явно чего-то не хватает.

Кину задание ну и мою реализацию. Можите одним глазком посмотреть.

Задание: Implement a simple point of sale.

Assume you have:
– one input device: bar codes scanner
– two output devices: LCD display and printer

Implement:
– single product sale: products bar code is scanned and:
– if the product is found in products database than it's name and price is printed on LCD
– if the product is not found than error message 'Product not found' is printed on LCD
– if the code scanned is empty than error message 'Invalid bar-code' is printed on LCD
– when 'exit' is input than receipt is printed on printer containing a list of all previously scanned items names and prices as well as total sum to be paid for all items; the total sum is also printed on LCD display

Rules:
– use only SDK classes and your favorite test libraries
– mock/stub the database and IO devices
– concentrate on proper design and clean code, rather than supplying fully functioning application

Класс SalePoint

public class SalePoint {
    private InputDevice codesScanner = new CodesScanner();
    private DBWorker dbWorker = null;
    private OutputDevice lcdDisplay = new LCDDisplay();
    private OutputDevice printer = new Printer();

    private List<Product> list = new ArrayList<Product>();

    public SalePoint(){
        try {
            dbWorker = new DBWorker();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void setDefaultBarCodes(){
        codesScanner.write("exit");
        codesScanner.write("");
        codesScanner.write("0000000001");
        codesScanner.write("0000000002");
    }


    public void run() {
        try {
            Product product = null;
            while(codesScanner.hasNext()) {
                String barCode = codesScanner.readLine();

                switch (barCode) {
                    case "":
                        lcdDisplay.printError("Product not found");
                        break;
                    case "exit":
                        printer.println("Printer: ");
                        printProducts();
                        return;
                    default:
                        product = dbWorker.findProduct(barCode);

                        if (product == null) {
                            lcdDisplay.printError("Invalid bar-code");
                        }

                        lcdDisplay.print(product);
                        list.add(product);
                }
            }

        } catch (EmptyStackException e) {
            e.printStackTrace();
        }
    }

    private void printProducts() {
        double summ = 0.0;

        for (Product product :
                list) {
            summ += product.getPrice();
        }

        ((Printer)printer).printProductsAndTotalPrice(list, summ);
    }
}

Class InputDevice

public class InputDevice {
    private Stack<String> buffer = new Stack<>();

    public void write(String message){
        buffer.push(message);
    }

    public String readLine(){
        if(buffer.isEmpty())
            return null;
        return buffer.pop();
    }

    public void clear(){
        buffer.clear();
    }

    public boolean hasNext(){
        return !buffer.isEmpty();
    }
}

Class CodesScanner

public class CodesScanner extends InputDevice{

    public CodesScanner() {
        super();
    }
// не знаю что добавить
}

Class OutputDevice

public class OutputDevice {
    void println(String message){
        System.out.println(message);
    }
    void print(String message){
        System.out.print(message);
    }
    void printError(String message){
        System.out.println("Error: " + message);
    }
    void print(Product product){
        System.out.println(product);
    }
}

Class LCDDisplay

public class LCDDisplay extends OutputDevice {
    public LCDDisplay() {
    }

    public void print(Product product){
        System.out.println(product.getName() + "\t\t" + product.getPrice());
    }

}

Class Printer

public class Printer extends OutputDevice {
    public Printer() {
        super();
    }

    public void printProducts(List<Product> productList){
        System.out.println("List of products:");
        for (Product product:
             productList) {
            System.out.println(product.getName() + "\t\t\t" + product.getPrice());
        }
    }

    public void printProductsAndTotalPrice(List<Product> productList, double totalPrice){
        System.out.println("List of products:\nName\t\t\tPrice");
        for (Product product:
                productList) {
            System.out.println(product.getName() + "\t\t\t" + product.getPrice());
        }
        System.out.println("Total:\t\t\t" + totalPrice);
    }

}

Class DBWorker

public class DBWorker {
    private static String URL = "jdbc:mysql://localhost:3306/mydbtest";
    private static String USERNAME = "root";
    private static String PASSWORD = "root";
    private static String SELECT = "SELECT product_name, price, bar_code FROM products WHERE bar_code = ?;";

    private Connection connection;

    public DBWorker() throws SQLException {
        Driver driver = new FabricMySQLDriver();
        DriverManager.registerDriver(driver);

        connection = DriverManager.getConnection(URL, USERNAME, PASSWORD);
    }

    public Product findProduct(String barCode) ;// урезано
}

Class Product

public class Product {
    private String name;
    private double price;
    private String barCode;

    public Product(String name, double price, String barCode) {
        this.name = name;
        this.price = price;
        this.barCode = barCode;
    }

    public Product() {
    }

    public Product(Product obj){
        this(obj.getName(), obj.getPrice(), obj.getBarCode());
    }


    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Product product = (Product) o;

        if (Double.compare(product.price, price) != 0) return false;
        if (name != null ? !name.equals(product.name) : product.name != null) return false;
        return barCode != null ? barCode.equals(product.barCode) : product.barCode == null;

    }

    @Override
    public int hashCode();// урезано

    @Override
    public String toString();// урезано
// сеттеры и геттеры
}

main

    public static void main(String[] args) {
        SalePoint salePoint = new SalePoint();

        salePoint.setDefaultBarCodes();
        salePoint.run();

    }

Извините за много кода.

Как на ваш взгляд что нужно доделать или переделать?

Да и по поводу тестирования пока смог написать только это:

public class DBTest {
    private static final Product PRODUCT = new Product("beer", 2.3, "0000000001");
    private static final String BAR_CODE = "0000000001";

    @Mock
    SalePoint salePoint;

    @Test
    public void testFindProduct(){
        DBWorker dbWorker = mock(DBWorker.class);

        when(dbWorker.findProduct(BAR_CODE)).thenReturn(new Product("beer", 2.3, "0000000001"));

        Product product = dbWorker.findProduct(BAR_CODE);

        Assert.assertEquals(product, PRODUCT);
    }

}