प्रेज़ेंटर और व्यू मॉडल

public class UserOutputData {
    private String firstName;
    private String lastName;
    private String email;
    private long registrationTimestamp; // epoch seconds

    public UserOutputData(String firstName, String lastName, String email, long registrationTimestamp) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
        this.registrationTimestamp = registrationTimestamp;
    }

    public String getFirstName() { return firstName; }
    public String getLastName() { return lastName; }
    public String getEmail() { return email; }
    public long getRegistrationTimestamp() { return registrationTimestamp; }
}

public class UserViewModel {
    private String fullName;
    private String formattedRegistrationDate;

    public UserViewModel(String fullName, String formattedRegistrationDate) {
        this.fullName = fullName;
        this.formattedRegistrationDate = formattedRegistrationDate;
    }

    public String getFullName() { return fullName; }
    public String getFormattedRegistrationDate() { return formattedRegistrationDate; }
}

import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;

public class UserPresenter {
    public UserViewModel present(UserOutputData outputData) {
        // Combine first and last name for display
        String fullName = outputData.getFirstName() + " " + outputData.getLastName();

        // Format the timestamp into a readable date string
        Instant instant = Instant.ofEpochSecond(outputData.getRegistrationTimestamp());
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm")
                                            .withZone(ZoneId.systemDefault());
        String formattedDate = formatter.format(instant);

        return new UserViewModel(fullName, formattedDate);
    }
}

import java.time.Instant;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;

// Simulate Use Case Output
class UserOutputData {
    private String firstName;
    private String lastName;
    private String email;
    private long registrationTimestamp;

    public UserOutputData(String firstName, String lastName, String email, long registrationTimestamp) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
        this.registrationTimestamp = registrationTimestamp;
    }

    public String getFirstName() { return firstName; }
    public String getLastName() { return lastName; }
    public String getEmail() { return email; }
    public long getRegistrationTimestamp() { return registrationTimestamp; }
}

// View Model for UI
class UserViewModel {
    private String fullName;
    private String formattedRegistrationDate;

    public UserViewModel(String fullName, String formattedRegistrationDate) {
        this.fullName = fullName;
        this.formattedRegistrationDate = formattedRegistrationDate;
    }

    public String getFullName() { return fullName; }
    public String getFormattedRegistrationDate() { return formattedRegistrationDate; }
}

// Presenter logic
class UserPresenter {
    public UserViewModel present(UserOutputData outputData) {
        String fullName = outputData.getFirstName() + " " + outputData.getLastName();

        Instant instant = Instant.ofEpochSecond(outputData.getRegistrationTimestamp());
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm")
                                            .withZone(ZoneId.systemDefault());
        String formattedDate = formatter.format(instant);

        return new UserViewModel(fullName, formattedDate);
    }
}

public class Main {
    public static void main(String[] args) {
        // 1. Simulate Use Case returning data
        UserOutputData userData = new UserOutputData(
            "Alice", "Smith", "alice@example.com", 1678886400L // March 15, 2023 12:00:00 PM UTC
        );

        // 2. Presenter transforms data
        UserPresenter presenter = new UserPresenter();
        UserViewModel viewModel = presenter.present(userData);

        // 3. UI "displays" the ViewModel
        System.out.println("Displaying User Profile:");
        System.out.println("Name: " + viewModel.getFullName());
        System.out.println("Registered: " + viewModel.getFormattedRegistrationDate());
    }
}