Solid -`D`

dip.md

📌 Dependency Inversion Principle (DIP) – To‘liq Tushuncha

DIP – bu S.O.L.I.D prinsiplarining oxirgisi bo‘lib, kuchli arxitekturali, test qilinadigan, kengaytiriladigan dasturlar yaratishga yordam beradi.

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📘 Ta’rif:

1. Yuqori darajadagi modullar past darajadagilarga bog‘lanmasin – ikkalasi abstraksiyaga (interfeysga) bog‘lansin.
2. Tafsilotlar (real klasslar) interfeyslarga bog‘liq bo‘lsin, aksincha emas.

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💡 Maqsad nima?

• Kod qismlarini mustaqil qilish
• Test yozishni osonlashtirish
• Yangi imkoniyatlar qo‘shishni osonlashtirish
• Kodni qayta ishlatish

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❌ DIP ga zid:

public class NotificationService
{
    public void Send()
    {
        var bot = new TelegramBotClient("TOKEN");
        bot.SendTextMessageAsync(123456, "Salom!");
    }
}

Bu klass TelegramBotClientga qattiq bog‘langan – test qilish yoki o‘zgartirish qiyin.

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✅ DIP ga mos:

1. Interfeys:

public interface IMessageSender
{
    Task SendMessageAsync(long userId, string message);
}

2. Implementatsiya:

public class TelegramSender : IMessageSender
{
    public Task SendMessageAsync(long userId, string msg)
    {
        Console.WriteLine($"Telegram: {msg}");
        return Task.CompletedTask;
    }
}

3. Yuqori darajadagi modul:

public class NotificationService
{
    private readonly IMessageSender _sender;
    public NotificationService(IMessageSender sender) => _sender = sender;

    public Task Notify(long id, string msg) => _sender.SendMessageAsync(id, msg);
}

4. Ishlatish:

var service = new NotificationService(new TelegramSender());
await service.Notify(123456, "Xush kelibsiz!");

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🧪 Test uchun Mock:

public class MockSender : IMessageSender
{
    public Task SendMessageAsync(long id, string msg)
    {
        Console.WriteLine($"[TEST]: {msg}");
        return Task.CompletedTask;
    }
}

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🌐 DIP qayerda kerak?

• Telegram botlarda (IMessageSender)
• Web API’larda (ILogger, IRepository, IEmailSender)
• Test yozishda (Mock sinflar)
• Microservice arxitekturasida

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✅ Xulosa

• Kod interfeyslarga bog‘lansin, real klasslarga emas
• Modullar mustaqil bo‘lsin
• Kengaytiriladigan, test qilinadigan tizim tuzilsin

"Yaxshi dasturchi kod yozadi, zo‘ri – mustahkam arxitektura quradi."

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