Connected to Event Collector

src/main/java/dev/mednikov/social/connections/events/FollowerCreatedEvent.java

@@ -0,0 +1,19 @@
+package dev.mednikov.social.connections.events;
+
+import dev.mednikov.social.connections.models.Follower;
+import org.springframework.context.ApplicationEvent;
+
+public final class FollowerCreatedEvent extends ApplicationEvent {
+
+    private final Follower follower;
+
+    public FollowerCreatedEvent(Object source, Follower follower) {
+        super(source);
+        this.follower = follower;
+    }
+
+    public Follower getFollower() {
+        return follower;
+    }
+
+}

src/main/java/dev/mednikov/social/connections/events/FollowerDeletedEvent.java

@@ -0,0 +1,23 @@
+package dev.mednikov.social.connections.events;
+
+import org.springframework.context.ApplicationEvent;
+
+public final class FollowerDeletedEvent extends ApplicationEvent {
+
+    private final Long followerUserId;
+    private final Long followedUserId;
+
+    public FollowerDeletedEvent(Object source, Long followerUserId, Long followedUserId) {
+        super(source);
+        this.followerUserId = followerUserId;
+        this.followedUserId = followedUserId;
+    }
+
+    public Long getFollowerUserId() {
+        return followerUserId;
+    }
+
+    public Long getFollowedUserId() {
+        return followedUserId;
+    }
+}

src/main/java/dev/mednikov/social/connections/messaging/AnalyticsEvent.java

@@ -0,0 +1,42 @@
+package dev.mednikov.social.connections.messaging;
+
+import java.time.LocalDateTime;
+
+final class AnalyticsEvent {
+
+    private String userId;
+    private String eventType;
+    private String timestamp;
+
+    AnalyticsEvent (){}
+
+    AnalyticsEvent(Long userId, String eventType){
+        this.userId = userId.toString();
+        this.eventType = eventType;
+        this.timestamp = LocalDateTime.now().toString();
+    }
+
+    String getUserId() {
+        return userId;
+    }
+
+    void setUserId(String userId) {
+        this.userId = userId;
+    }
+
+    String getEventType() {
+        return eventType;
+    }
+
+    void setEventType(String eventType) {
+        this.eventType = eventType;
+    }
+
+    String getTimestamp() {
+        return timestamp;
+    }
+
+    void setTimestamp(String timestamp) {
+        this.timestamp = timestamp;
+    }
+}

src/main/java/dev/mednikov/social/connections/messaging/MessageService.java

@@ -0,0 +1,54 @@
+package dev.mednikov.social.connections.messaging;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import dev.mednikov.social.connections.events.FollowerCreatedEvent;
+import dev.mednikov.social.connections.events.FollowerDeletedEvent;
+import dev.mednikov.social.connections.models.Follower;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.context.event.EventListener;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Component;
+
+@Component
+public class MessageService {
+
+    private final static Logger logger = LoggerFactory.getLogger(MessageService.class);
+
+    private final ObjectMapper objectMapper;
+    private final RabbitTemplate rabbitTemplate;
+
+    public MessageService(ObjectMapper objectMapper, RabbitTemplate rabbitTemplate) {
+        this.objectMapper = objectMapper;
+        this.rabbitTemplate = rabbitTemplate;
+    }
+
+    @EventListener
+    @Async
+    public void onFollowerCreatedEventListener(FollowerCreatedEvent event) {
+        Follower follower = event.getFollower();
+        Long userId = follower.getOwner().getId();
+        AnalyticsEvent analyticsEvent = new AnalyticsEvent(userId, "followers_created");
+        try {
+            String payload = this.objectMapper.writeValueAsString(analyticsEvent);
+            this.rabbitTemplate.convertAndSend("", "social_events", payload);
+            logger.info("Event collector: follower created event sent");
+        } catch (Exception ex){
+            logger.error(ex.getMessage());
+        }
+    }
+
+    @EventListener
+    @Async
+    public void onFollowerDeletedEventListener(FollowerDeletedEvent event) {
+        AnalyticsEvent analyticsEvent = new AnalyticsEvent(event.getFollowerUserId(), "followers_deleted");
+        try {
+            String payload = this.objectMapper.writeValueAsString(analyticsEvent);
+            this.rabbitTemplate.convertAndSend("", "social_events", payload);
+            logger.info("Event collector: follower deleted event sent");
+        } catch (Exception ex){
+            logger.error(ex.getMessage());
+        }
+    }
+}

src/main/java/dev/mednikov/social/connections/services/FollowerServiceImpl.java

@@ -3,6 +3,8 @@ package dev.mednikov.social.connections.services;
 import dev.mednikov.social.connections.domain.CreateFollowerRequestDto;
 import dev.mednikov.social.connections.domain.FollowerDto;
 import dev.mednikov.social.connections.domain.FollowerDtoMapper;
+import dev.mednikov.social.connections.events.FollowerCreatedEvent;
+import dev.mednikov.social.connections.events.FollowerDeletedEvent;
 import dev.mednikov.social.connections.exceptions.FollowerAlreadyExistsException;
 import dev.mednikov.social.connections.exceptions.UserDoesNotExistException;
 import dev.mednikov.social.connections.models.Follower;
@@ -10,6 +12,7 @@ import dev.mednikov.social.connections.models.User;
 import dev.mednikov.social.connections.repositories.FollowerRepository;
 import dev.mednikov.social.connections.repositories.IdentifierGenerator;
 import dev.mednikov.social.connections.repositories.UserRepository;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.stereotype.Service;
 
 import java.util.Optional;
@@ -22,14 +25,17 @@ public class FollowerServiceImpl implements FollowerService {
     private final FollowerRepository followerRepository;
     private final UserRepository userRepository;
     private final IdentifierGenerator identifierGenerator;
+    private final ApplicationEventPublisher eventPublisher;
 
     public FollowerServiceImpl(
             FollowerRepository followerRepository,
             UserRepository userRepository,
-            IdentifierGenerator identifierGenerator) {
+            IdentifierGenerator identifierGenerator,
+            ApplicationEventPublisher eventPublisher) {
         this.followerRepository = followerRepository;
         this.userRepository = userRepository;
         this.identifierGenerator = identifierGenerator;
+        this.eventPublisher = eventPublisher;
     }
 
     @Override
@@ -61,13 +67,22 @@ public class FollowerServiceImpl implements FollowerService {
         follower.setId(this.identifierGenerator.getNextId());
 
         Follower savedFollower = this.followerRepository.save(follower);
-
+        FollowerCreatedEvent event = new FollowerCreatedEvent(this, savedFollower);
+        this.eventPublisher.publishEvent(event);
         return mapper.apply(savedFollower);
     }
 
     @Override
     public void deleteFollower(Long id) {
-        this.followerRepository.deleteById(id);
+        Optional<Follower> result = this.followerRepository.findById(id);
+        if (result.isPresent()) {
+            Follower follower = result.get();
+            Long followerUserId = follower.getOwner().getId();
+            Long followedUserId = follower.getFollowedUser().getId();
+            FollowerDeletedEvent event = new FollowerDeletedEvent(this, followerUserId, followedUserId);
+            this.eventPublisher.publishEvent(event);
+            this.followerRepository.deleteById(id);
+        }
     }
 
 }