SOLID এর মধ্যে নীতি প্রয়োগ করা Java: উদাহরণ এবং সর্বোত্তম অনুশীলন

class UserManager {  
  void createUser(UserData userData) {  
    // Logic for creating a user  
  }  
}  
  
class EmailService {  
  void sendEmail(EmailData emailData) {  
    // Logic for sending an email  
  }  
}  

abstract class PaymentProcessor {  
  abstract void processPayment();  
}  
  
class CreditCardPaymentProcessor extends PaymentProcessor {  
  void processPayment() {  
    // Logic for processing credit card payment  
  }  
}  
  
class PayPalPaymentProcessor extends PaymentProcessor {  
  void processPayment() {  
    // Logic for processing PayPal payment  
  }  
}  

abstract class Shape {  
  abstract double area();  
}  
  
class Rectangle extends Shape {  
  double area() {  
    // Logic for calculating area of rectangle  
  }  
}  
  
class Square extends Shape {  
  double area() {  
    // Logic for calculating area of square  
  }  
}  

interface UpdateableFeature {  
  void updateFeature();  
}  
  
interface DisplayableFeature {  
  void displayFeature();  
}  

class OrderProcessor {  
  private final DBConnection dbConnection;  
  private final EmailService emailService;  
  
  OrderProcessor(DBConnection dbConnection, EmailService emailService) {  
    this.dbConnection = dbConnection;  
    this.emailService = emailService;  
  }  
}