MapSimpleSubscription.java

/*
 * Copyright 2016 higherfrequencytrading.com
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package net.openhft.chronicle.engine.pubsub;

import net.openhft.chronicle.bytes.BytesStore;
import net.openhft.chronicle.core.Jvm;
import net.openhft.chronicle.engine.api.pubsub.InvalidSubscriberException;
import net.openhft.chronicle.engine.api.pubsub.Reference;
import net.openhft.chronicle.engine.api.pubsub.Subscriber;
import net.openhft.chronicle.engine.api.pubsub.SubscriptionConsumer;
import net.openhft.chronicle.engine.api.tree.RequestContext;
import net.openhft.chronicle.engine.query.Filter;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.function.Function;

/**
 * Created by peter on 29/05/15.
 */
public class MapSimpleSubscription<E> implements SimpleSubscription<E> {

    private static final Logger LOG = LoggerFactory.getLogger(MapSimpleSubscription.class);
    private final Set<Subscriber<E>> subscribers = new CopyOnWriteArraySet<>();
    private final Reference<E> currentValue;
    private final Function<Object, E> valueReader;
    private volatile boolean closed = true;

    public MapSimpleSubscription(Reference<E> reference, Function<Object, E> valueReader) {
        this.currentValue = reference;
        this.valueReader = valueReader;
    }

    @Override
    public void registerSubscriber(@NotNull RequestContext rc,
                                   @NotNull Subscriber<E> subscriber,
                                   @NotNull Filter<E> filter) {
        subscribers.add(subscriber);
        if (rc.bootstrap() != Boolean.FALSE)
            try {
                subscriber.onMessage(currentValue.get());
            } catch (InvalidSubscriberException e) {
                subscribers.remove(subscriber);
            }
    }

    @Override
    public void unregisterSubscriber(@NotNull Subscriber subscriber) {
        subscribers.remove(subscriber);
        subscriber.onEndOfSubscription();
    }

    @Override
    public int keySubscriberCount() {
        return subscriberCount();
    }

    @Override
    public int entrySubscriberCount() {
        return 0;
    }

    @Override
    public int topicSubscriberCount() {
        return 0;
    }

    @Override
    public int subscriberCount() {
        return subscribers.size();
    }

    @Override
    public void notifyMessage(Object e) {
        try {
            @Nullable E ee = e instanceof BytesStore ? valueReader.apply(e) : (E) e;
            SubscriptionConsumer.notifyEachSubscriber(subscribers, s -> s.onMessage(ee));
        } catch (ClassCastException e1) {
            if (LOG.isDebugEnabled())
                Jvm.debug().on(getClass(), "Is " + valueReader + " the correct ValueReader?");
            throw e1;
        }
    }

    @Override
    public void close() {
        if (isClosed())
            return;
        closed = true;

        for (@NotNull Subscriber<E> subscriber : subscribers) {
            try {
                subscriber.onEndOfSubscription();
            } catch (Exception e) {
                Jvm.debug().on(getClass(), e);
            }
        }
    }

    @Override
    public boolean isClosed() {
        return closed;
    }
}