backend-development-with-java/design_pattern/DependencyInjection.java at main · mdarafat1819/backend-development-with-java · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
interface MessageService {
    public void send();
}

class EmailService implements MessageService {
    @Override
    public void send() {
        System.out.println("Sending email message");
    }
}

class SmsService implements MessageService {
    @Override
    public void send() {
        System.out.println("Sending SMS message");
    }
}

class NotificationService {
    private final MessageService messageService;

    public NotificationService(MessageService messageService) {
        this.messageService = messageService;
    }

    public void notifyUser() {
        messageService.send();
    }

}
public class DependencyInjection {
    public static void main(String[] args) {
        NotificationService notificationService = new NotificationService(new EmailService());
        notificationService.notifyUser();

        notificationService = new NotificationService(new SmsService());
        notificationService.notifyUser();

    }
}