public synchronized Values next()

in core/src/main/java/org/apache/stormcrawler/persistence/urlbuffer/SchedulingURLBuffer.java [74:126]
37 lines of code
7 McCabe index (conditional complexity)

    public synchronized Values next() {

        do {
            Iterator<Entry<String, Queue<URLMetadata>>> i = queues.entrySet().iterator();

            if (!i.hasNext()) {
                LOG.trace("Empty iterator");
                return null;
            }

            Map.Entry<String, Queue<URLMetadata>> nextEntry = i.next();

            Queue<URLMetadata> queue = nextEntry.getValue();
            String queueName = nextEntry.getKey();

            // remove the entry, gets added back later
            i.remove();

            LOG.trace("Next queue {}", queueName);

            URLMetadata item = null;

            // is this queue ready to be processed?
            if (canRelease(queueName)) {
                // try the first element
                item = queue.poll();
                LOG.trace("Item {}", item.url);
            } else {
                LOG.trace("Queue {} not ready to release yet", queueName);
            }

            // any left? add to the end of the iterator
            if (!queue.isEmpty()) {
                LOG.debug("Adding to the back of the queue {}", queueName);
                queues.put(queueName, queue);
            }
            // notify that the queue is empty
            else {
                if (listener != null) {
                    listener.emptyQueue(queueName);
                }
            }

            if (item != null) {
                lastReleased.put(queueName, Instant.now());
                unacked.put(item.url, new Object[] {Instant.now(), queueName});
                // remove it from the list of URLs in the queue
                in_buffer.remove(item.url);
                return new Values(item.url, item.metadata);
            }
        } while (!queues.isEmpty());
        return null;
    }