pl.allegro.tech.hermes.consumers.subscription.cache.NotificationsBasedSubscriptionCache Maven / Gradle / Ivy

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Fast and reliable message broker built on top of Kafka.
There is a newer version: 2.10.0
package pl.allegro.tech.hermes.consumers.subscription.cache;

import pl.allegro.tech.hermes.api.Subscription;
import pl.allegro.tech.hermes.api.SubscriptionName;
import pl.allegro.tech.hermes.api.TopicName;
import pl.allegro.tech.hermes.domain.group.GroupRepository;
import pl.allegro.tech.hermes.domain.notifications.InternalNotificationsBus;
import pl.allegro.tech.hermes.domain.notifications.SubscriptionCallback;
import pl.allegro.tech.hermes.domain.subscription.SubscriptionRepository;
import pl.allegro.tech.hermes.domain.topic.TopicRepository;

import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;

public class NotificationsBasedSubscriptionCache implements SubscriptionsCache, SubscriptionCallback {

    private final Map subscriptions = new ConcurrentHashMap<>();

    private final GroupRepository groupRepository;

    private final TopicRepository topicRepository;

    private final SubscriptionRepository subscriptionRepository;

    public NotificationsBasedSubscriptionCache(InternalNotificationsBus notificationsBus,
                                               GroupRepository groupRepository,
                                               TopicRepository topicRepository,
                                               SubscriptionRepository subscriptionRepository) {
        notificationsBus.registerSubscriptionCallback(this);
        this.groupRepository = groupRepository;
        this.topicRepository = topicRepository;
        this.subscriptionRepository = subscriptionRepository;
    }

    @Override
    public void onSubscriptionCreated(Subscription subscription) {
        this.subscriptions.put(subscription.getQualifiedName(), subscription);
    }

    @Override
    public void onSubscriptionRemoved(Subscription subscription) {
        this.subscriptions.remove(subscription.getQualifiedName(), subscription);
    }

    @Override
    public void onSubscriptionChanged(Subscription subscription) {
        this.subscriptions.put(subscription.getQualifiedName(), subscription);
    }

    @Override
    public Subscription getSubscription(SubscriptionName subscriptionName) {
        return subscriptions.get(subscriptionName);
    }

    @Override
    public List subscriptionsOfTopic(TopicName topicName) {
        return subscriptions.values().stream()
                .filter(s -> s.getTopicName().equals(topicName))
                .collect(Collectors.toList());
    }

    @Override
    public List listActiveSubscriptionNames() {
        return subscriptions.values().stream()
                .filter(Subscription::isActive)
                .map(Subscription::getQualifiedName)
                .collect(Collectors.toList());
    }

    @Override
    public void start() {
        for (String groupName : groupRepository.listGroupNames()) {
            for (String topicName : topicRepository.listTopicNames(groupName)) {
                for (Subscription subscription : subscriptionRepository.listSubscriptions(new TopicName(groupName, topicName))) {
                    subscriptions.put(subscription.getQualifiedName(), subscription);
                }
            }
        }
    }
}