Examples with AbstractCloseableIterator co.cask.cdap.api.dataset.lib.AbstractCloseableIterator used on opensource projects

Example 6 with AbstractCloseableIterator

use of co.cask.cdap.api.dataset.lib.AbstractCloseableIterator in project cdap by caskdata.

the class LevelDBMetadataTable method scanTopics.

private CloseableIterator<TopicMetadata> scanTopics(@Nullable byte[] startKey, @Nullable byte[] stopKey) throws IOException {
    final CloseableIterator<Map.Entry<byte[], byte[]>> iterator = new DBScanIterator(levelDB, startKey, stopKey);
    return new AbstractCloseableIterator<TopicMetadata>() {

        private boolean closed = false;

        @Override
        protected TopicMetadata computeNext() {
            if (closed || (!iterator.hasNext())) {
                return endOfData();
            }
            Map.Entry<byte[], byte[]> entry = iterator.next();
            TopicId topicId = MessagingUtils.toTopicId(entry.getKey());
            Map<String, String> properties = GSON.fromJson(Bytes.toString(entry.getValue()), MAP_TYPE);
            return new TopicMetadata(topicId, properties);
        }

        @Override
        public void close() {
            try {
                iterator.close();
            } finally {
                endOfData();
                closed = true;
            }
        }
    };
}