Examples with NakadiCursor org.zalando.nakadi.domain.NakadiCursor used on opensource projects

Example 56 with NakadiCursor

use of org.zalando.nakadi.domain.NakadiCursor in project nakadi by zalando.

the class MultiTimelineEventConsumer method selectCorrectTopicRepo.

private TopicRepository selectCorrectTopicRepo(final NakadiCursor cursor, final Consumer<NakadiCursor> cursorReplacer, final Consumer<NakadiCursor> lastTimelinePosition) throws ServiceUnavailableException {
    final List<Timeline> eventTimelines = eventTypeTimelines.get(cursor.getEventType());
    final ListIterator<Timeline> itTimeline = eventTimelines.listIterator(eventTimelines.size());
    // select last timeline, and then move back until position was found.
    Timeline electedTimeline = itTimeline.previous();
    while (itTimeline.hasPrevious()) {
        final Timeline toCheck = itTimeline.previous();
        final NakadiCursor latest = toCheck.calculateNakadiLatestPosition(cursor.getPartition());
        if (latest == null) {
            electedTimeline = toCheck;
        } else if (comparator.compare(latest, cursor) > 0) {
            // There is a border case - latest is equal to begin (that means that there are no available events
            // there), and one should position on timeline that have something inside.
            final NakadiCursor firstItem = timelineService.getTopicRepository(toCheck).loadPartitionStatistics(toCheck, cursor.getPartition()).get().getFirst();
            if (comparator.compare(latest, firstItem) >= 0) {
                electedTimeline = toCheck;
            } else {
                LOG.info("Timeline {} is empty, skipping", toCheck);
            }
        } else {
            break;
        }
    }
    final TopicRepository result = timelineService.getTopicRepository(electedTimeline);
    if (electedTimeline.getOrder() != cursor.getTimeline().getOrder()) {
        // It seems that cursor jumped to different timeline. One need to fetch very first cursor in timeline.
        final NakadiCursor replacement = getBeforeFirstCursor(result, electedTimeline, cursor.getPartition());
        LOG.info("Replacing cursor because of jumping between timelines from {} to {}", cursor, replacement);
        cursorReplacer.accept(replacement);
    }
    lastTimelinePosition.accept(electedTimeline.calculateNakadiLatestPosition(cursor.getPartition()));
    return result;
}