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Efficient reliable UDP unicast, UDP multicast, and IPC transport protocol.
There is a newer version: 1.48.0
/*
 * Copyright 2014-2024 Real Logic Limited.
 *
 * 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
 *
 * https://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.archive.client;

import io.aeron.Aeron;
import io.aeron.Subscription;
import io.aeron.archive.codecs.MessageHeaderDecoder;
import io.aeron.archive.codecs.RecordingProgressDecoder;
import io.aeron.archive.codecs.RecordingStartedDecoder;
import io.aeron.archive.codecs.RecordingStoppedDecoder;
import io.aeron.logbuffer.ControlledFragmentHandler;
import io.aeron.logbuffer.Header;
import org.agrona.DirectBuffer;

/**
 * Encapsulate the polling and decoding of recording events.
 */
public final class RecordingEventsPoller implements ControlledFragmentHandler
{
    private final MessageHeaderDecoder messageHeaderDecoder = new MessageHeaderDecoder();
    private final RecordingStartedDecoder recordingStartedDecoder = new RecordingStartedDecoder();
    private final RecordingProgressDecoder recordingProgressDecoder = new RecordingProgressDecoder();
    private final RecordingStoppedDecoder recordingStoppedDecoder = new RecordingStoppedDecoder();

    private final Subscription subscription;
    private int templateId;
    private boolean isPollComplete;

    private long recordingId;
    private long recordingStartPosition;
    private long recordingPosition;
    private long recordingStopPosition;

    /**
     * Create a poller for a given subscription to an archive for recording events.
     *
     * @param subscription to poll for new events.
     */
    public RecordingEventsPoller(final Subscription subscription)
    {
        this.subscription = subscription;
    }

    /**
     * Poll for recording events.
     *
     * @return the number of fragments read during the operation. Zero if no events are available.
     */
    public int poll()
    {
        if (isPollComplete)
        {
            isPollComplete = false;
            templateId = Aeron.NULL_VALUE;
        }

        return subscription.controlledPoll(this, 1);
    }

    /**
     * Has the last polling action received a complete message?
     *
     * @return true of the last polling action received a complete message?
     */
    public boolean isPollComplete()
    {
        return isPollComplete;
    }

    /**
     * Get the template id of the last received message.
     *
     * @return the template id of the last received message.
     */
    public int templateId()
    {
        return templateId;
    }

    /**
     * Get the recording id of the last received event.
     *
     * @return the recording id of the last received event.
     */
    public long recordingId()
    {
        return recordingId;
    }

    /**
     * Get the position the recording started at.
     *
     * @return the position the recording started at.
     */
    public long recordingStartPosition()
    {
        return recordingStartPosition;
    }

    /**
     * Get the current recording position.
     *
     * @return the current recording position.
     */
    public long recordingPosition()
    {
        return recordingPosition;
    }

    /**
     * Get the position the recording stopped at.
     *
     * @return the position the recording stopped at.
     */
    public long recordingStopPosition()
    {
        return recordingStopPosition;
    }

    /**
     * {@inheritDoc}
     */
    public ControlledFragmentHandler.Action onFragment(
        final DirectBuffer buffer, final int offset, final int length, final Header header)
    {
        if (isPollComplete)
        {
            return ControlledFragmentHandler.Action.ABORT;
        }

        messageHeaderDecoder.wrap(buffer, offset);

        final int schemaId = messageHeaderDecoder.schemaId();
        if (schemaId != MessageHeaderDecoder.SCHEMA_ID)
        {
            throw new ArchiveException("expected schemaId=" + MessageHeaderDecoder.SCHEMA_ID + ", actual=" + schemaId);
        }

        templateId = messageHeaderDecoder.templateId();
        switch (templateId)
        {
            case RecordingStartedDecoder.TEMPLATE_ID:
                recordingStartedDecoder.wrap(
                    buffer,
                    offset + MessageHeaderDecoder.ENCODED_LENGTH,
                    messageHeaderDecoder.blockLength(),
                    messageHeaderDecoder.version());

                recordingId = recordingStartedDecoder.recordingId();
                recordingStartPosition = recordingStartedDecoder.startPosition();
                recordingPosition = recordingStartPosition;
                recordingStopPosition = Aeron.NULL_VALUE;
                isPollComplete = true;
                return ControlledFragmentHandler.Action.BREAK;

            case RecordingProgressDecoder.TEMPLATE_ID:
                recordingProgressDecoder.wrap(
                    buffer,
                    offset + MessageHeaderDecoder.ENCODED_LENGTH,
                    messageHeaderDecoder.blockLength(),
                    messageHeaderDecoder.version());

                recordingId = recordingProgressDecoder.recordingId();
                recordingStartPosition = recordingProgressDecoder.startPosition();
                recordingPosition = recordingProgressDecoder.position();
                recordingStopPosition = Aeron.NULL_VALUE;
                isPollComplete = true;
                return ControlledFragmentHandler.Action.BREAK;

            case RecordingStoppedDecoder.TEMPLATE_ID:
                recordingStoppedDecoder.wrap(
                    buffer,
                    offset + MessageHeaderDecoder.ENCODED_LENGTH,
                    messageHeaderDecoder.blockLength(),
                    messageHeaderDecoder.version());

                recordingId = recordingStoppedDecoder.recordingId();
                recordingStartPosition = recordingStoppedDecoder.startPosition();
                recordingStopPosition = recordingStoppedDecoder.stopPosition();
                recordingPosition = recordingStopPosition;
                isPollComplete = true;
                return ControlledFragmentHandler.Action.BREAK;
        }

        return ControlledFragmentHandler.Action.CONTINUE;
    }
}