org.apache.james.mailbox.events.InVMEventBus.java Source code

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Here is the source code for org.apache.james.mailbox.events.InVMEventBus.java

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package org.apache.james.mailbox.events;

import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.james.mailbox.Event;
import org.apache.james.mailbox.MailboxListener;
import org.apache.james.mailbox.events.delivery.EventDelivery;

import com.github.steveash.guavate.Guavate;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;

import reactor.core.publisher.Mono;

public class InVMEventBus implements EventBus {
    private final Multimap<RegistrationKey, MailboxListener> registrations;
    private final ConcurrentHashMap<Group, MailboxListener> groups;
    private final EventDelivery eventDelivery;

    InVMEventBus(EventDelivery eventDelivery) {
        this.eventDelivery = eventDelivery;
        this.registrations = Multimaps.synchronizedSetMultimap(HashMultimap.create());
        this.groups = new ConcurrentHashMap<>();
    }

    @Override
    public Registration register(MailboxListener listener, RegistrationKey key) {
        registrations.put(key, listener);
        return () -> registrations.remove(key, listener);
    }

    @Override
    public Registration register(MailboxListener listener, Group group) {
        MailboxListener previous = groups.putIfAbsent(group, listener);
        if (previous == null) {
            return () -> groups.remove(group, listener);
        }
        throw new GroupAlreadyRegistered(group);
    }

    @Override
    public Mono<Void> dispatch(Event event, Set<RegistrationKey> keys) {
        if (!event.isNoop()) {
            return eventDelivery.deliver(registeredListeners(keys), event).synchronousListenerFuture();
        }
        return Mono.empty();
    }

    private Set<MailboxListener> registeredListeners(Set<RegistrationKey> keys) {
        return ImmutableSet.<MailboxListener>builder().addAll(groups.values())
                .addAll(keys.stream().flatMap(registrationKey -> registrations.get(registrationKey).stream())
                        .collect(Guavate.toImmutableList()))
                .build();
    }

}