DriverProxy.java

/*
 * Copyright 2014-2017 Real Logic Ltd.
 *
 * 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 io.aeron;

import io.aeron.command.*;
import org.agrona.concurrent.UnsafeBuffer;
import org.agrona.concurrent.ringbuffer.RingBuffer;

import static io.aeron.command.ControlProtocolEvents.*;
import static org.agrona.BitUtil.CACHE_LINE_LENGTH;
import static org.agrona.BufferUtil.allocateDirectAligned;

/**
 * Separates the concern of communicating with the client conductor away from the rest of the client.
 *
 * Writes commands into the client conductor buffer.
 *
 * Note: this class is not thread safe and is expecting to be called under the {@link ClientConductor} main lock.
 */
public class DriverProxy
{
    /** Maximum capacity of the write buffer */
    public static final int MSG_BUFFER_CAPACITY = 1024;

    private final UnsafeBuffer buffer = new UnsafeBuffer(
        allocateDirectAligned(MSG_BUFFER_CAPACITY, CACHE_LINE_LENGTH * 2));
    private final PublicationMessageFlyweight publicationMessage = new PublicationMessageFlyweight();
    private final SubscriptionMessageFlyweight subscriptionMessage = new SubscriptionMessageFlyweight();
    private final RemoveMessageFlyweight removeMessage = new RemoveMessageFlyweight();
    private final CorrelatedMessageFlyweight correlatedMessage = new CorrelatedMessageFlyweight();
    private final DestinationMessageFlyweight destinationMessage = new DestinationMessageFlyweight();
    private final RingBuffer toDriverCommandBuffer;

    public DriverProxy(final RingBuffer toDriverCommandBuffer)
    {
        this.toDriverCommandBuffer = toDriverCommandBuffer;

        publicationMessage.wrap(buffer, 0);
        subscriptionMessage.wrap(buffer, 0);
        correlatedMessage.wrap(buffer, 0);
        removeMessage.wrap(buffer, 0);
        destinationMessage.wrap(buffer, 0);

        final long clientId = toDriverCommandBuffer.nextCorrelationId();
        correlatedMessage.clientId(clientId);
    }

    public long timeOfLastDriverKeepaliveMs()
    {
        return toDriverCommandBuffer.consumerHeartbeatTime();
    }

    public long addPublication(final String channel, final int streamId)
    {
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        publicationMessage.correlationId(correlationId);
        publicationMessage
            .streamId(streamId)
            .channel(channel);

        if (!toDriverCommandBuffer.write(ADD_PUBLICATION, buffer, 0, publicationMessage.length()))
        {
            throw new IllegalStateException("Could not write add publication command");
        }

        return correlationId;
    }

    public long addExclusivePublication(final String channel, final int streamId)
    {
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        publicationMessage.correlationId(correlationId);
        publicationMessage
            .streamId(streamId)
            .channel(channel);

        if (!toDriverCommandBuffer.write(ADD_EXCLUSIVE_PUBLICATION, buffer, 0, publicationMessage.length()))
        {
            throw new IllegalStateException("Could not write add exclusive publication command");
        }

        return correlationId;
    }

    public long removePublication(final long registrationId)
    {
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        removeMessage
            .registrationId(registrationId)
            .correlationId(correlationId);

        if (!toDriverCommandBuffer.write(REMOVE_PUBLICATION, buffer, 0, RemoveMessageFlyweight.length()))
        {
            throw new IllegalStateException("Could not write remove publication command");
        }

        return correlationId;
    }

    public long addSubscription(final String channel, final int streamId)
    {
        final long registrationId = -1;
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        subscriptionMessage.correlationId(correlationId);
        subscriptionMessage
            .registrationCorrelationId(registrationId)
            .streamId(streamId)
            .channel(channel);

        if (!toDriverCommandBuffer.write(ADD_SUBSCRIPTION, buffer, 0, subscriptionMessage.length()))
        {
            throw new IllegalStateException("Could not write add subscription command");
        }

        return correlationId;
    }

    public long removeSubscription(final long registrationId)
    {
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        removeMessage
            .registrationId(registrationId)
            .correlationId(correlationId);

        if (!toDriverCommandBuffer.write(REMOVE_SUBSCRIPTION, buffer, 0, RemoveMessageFlyweight.length()))
        {
            throw new IllegalStateException("Could not write remove subscription message");
        }

        return correlationId;
    }

    public void sendClientKeepalive()
    {
        correlatedMessage.correlationId(0);

        if (!toDriverCommandBuffer.write(CLIENT_KEEPALIVE, buffer, 0, CorrelatedMessageFlyweight.LENGTH))
        {
            throw new IllegalStateException("Could not send client keepalive command");
        }
    }

    public long addDestination(final long registrationId, final String endpointChannel)
    {
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        destinationMessage
            .registrationCorrelationId(registrationId)
            .channel(endpointChannel)
            .correlationId(correlationId);

        if (!toDriverCommandBuffer.write(ADD_DESTINATION, buffer, 0, destinationMessage.length()))
        {
            throw new IllegalStateException("Could not write destination command");
        }

        return correlationId;
    }

    public long removeDestination(final long registrationId, final String endpointChannel)
    {
        final long correlationId = toDriverCommandBuffer.nextCorrelationId();

        destinationMessage
            .registrationCorrelationId(registrationId)
            .channel(endpointChannel)
            .correlationId(correlationId);

        if (!toDriverCommandBuffer.write(REMOVE_DESTINATION, buffer, 0, destinationMessage.length()))
        {
            throw new IllegalStateException("Could not write destination command");
        }

        return correlationId;
    }
}