Public class

public class OrderProcessor {

public void process(Order order){
MySQLOrderRepository repository = new MySQLOrderRepository();

ConfirmationEmailSender mailSender = new ConfirmationEmailSender();
if (order.isValid() && repository.save(order)) {

mailSender.sendConfirmationEmail(order);

}

}
}

Ushbu misolda bizning OrderProcessor MySQLOrderRepository va ConfirmationEmailSender ikkita aniq sinflariga bog'liq. Keling, ushbu sinflarning kodini beraylik:
public class MySQLOrderRepository {

public boolean save(Order order) {

MySqlConnection connection = new MySqlConnection("database.url");

// buyurtmani ma'lumotlar bazasiga saqlash
return true;

}

}
public class ConfirmationEmailSender {

public void sendConfirmationEmail(Order order) {

String name = order.getCustomerName();

String email = order.getCustomerEmail();
// Biz mijozga xat yuboramiz

}

}

Ushbu sinflar abstrakt deb nomlanishdan yiroq. Va DIP printsipi nuqtai nazaridan, kelajakda muayyan dasturlar bilan emas, balki ular bilan ishlashga imkon beradigan ba'zi bir abstraktsiyalarni yaratishdan boshlash to'g'ri bo'lar edi. Keling, ikkita abonentga aylanadigan MailSender va OrderRepository interfeyslarini yarataylik:

public interface MailSender {

void sendConfirmationEmail(Order order);

}
public interface OrderRepository {

boolean save(Order order);

}

Endi biz ushbu interfeyslarni bunga tayyor bo'lgan sinflarda qo'llaymiz:
public class ConfirmationEmailSender implements MailSender {
@Override

public void sendConfirmationEmail(Order order) {

String name = order.getCustomerName();

String email = order.getCustomerEmail();
// Biz mijozga xat yuboramiz

}
}
public class MySQLOrderRepository implements OrderRepository {
@Override

public boolean save(Order order) {

MySqlConnection connection = new MySqlConnection("database.url");

// buyurtmani ma'lumotlar bazasiga saqlash
return true;

}

}

OrderProcessor sinfimiz aniq tafsilotlarga emas, abstraktsiyalarga bog'liq bo'lishi uchun biz ba'zi tayyorgarlik ishlarini olib bordik. Keling, sinf konstruktoriga bog'liqliklarni kiritish orqali unga o'zgartirish kiritaylik:

public class OrderProcessor {
private MailSender mailSender;

private OrderRepository repository;
public OrderProcessor(MailSender mailSender, OrderRepository repository) {

this.mailSender = mailSender;

this.repository = repository;

}
public void process(Order order){

if (order.isValid() && repository.save(order)) {

mailSender.sendConfirmationEmail(order);

}

}

}

Endi bizning sinfimiz konkret dasturlardan ko'ra abstraktsiyalarga bog'liq. Siz o'zingizning xatti-harakatlaringizni OrderProcessor nusxasini yaratishda kerakli bog'liqlikni kiritish orqali osongina o'zgartirishingiz mumkin.
Topshir:

1. 
   Tanlangan obekt bo’yicha 5 ta SOLID tamoillarini tadbiq etish