* supported, nor is the {@link #remove()} method.
 *
 * <p>Example:
 *
 * {@snippet :
 * Iterator<Integer> powersOfTwo =
 *     new AbstractSequentialIterator<Integer>(1) {
 *       protected Integer computeNext(Integer previous) {
 *         return (previous == 1 << 30) ? null : previous * 2;
 *       }
 *     };
 * }
 *
 * @author Chris Povirk

  private State state = State.NOT_READY;

  protected AbstractIterator() {}

  private enum State {
    READY,
    NOT_READY,
    DONE,
    FAILED,
  }

  private @Nullable T next;

  protected abstract @Nullable T computeNext();

  @CanIgnoreReturnValue
  protected final @Nullable T endOfData() {
    state = State.DONE;
    return null;
  }

  @Override

     * {@inheritDoc}
     *
     * @see jcifs.internal.smb2.ServerMessageBlock2Request#createResponse(jcifs.CIFSContext,
     *      jcifs.internal.smb2.ServerMessageBlock2Request)
     */
    @Override
    protected Smb2QueryDirectoryResponse createResponse(final CIFSContext tc,
            final ServerMessageBlock2Request<Smb2QueryDirectoryResponse> req) {
        return new Smb2QueryDirectoryResponse(tc.getConfig(), this.fileInformationClass);

     *
     * @see jcifs.internal.smb2.RequestWithFileId#setFileId(byte[])
     */
    @Override
    public void setFileId(final byte[] fileId) {
        this.fileId = fileId;
    }

    @Override
    protected Smb2WriteResponse createResponse(final CIFSContext tc, final ServerMessageBlock2Request<Smb2WriteResponse> req) {
        return new Smb2WriteResponse(tc.getConfig());
    }

    /**

        private String name;

        public TestDataStore(String name) {
            this.name = name;
        }

        @Override
        protected String getName() {
            return name;
        }

        @Override
        protected void storeData(DataConfig dataConfig, IndexUpdateCallback callback, DataStoreParams paramMap,
                Map<String, String> scriptMap, Map<String, Object> defaultDataMap) {

        WARN,
        /** Error */
        ERROR,
        /** Fatal */
        FATAL,
    }

    /** Factory for LoggerAdapter */
    protected static final LoggerAdapterFactory factory = getLoggerAdapterFactory();

    /** Map of loggers keyed by class */
    protected static final Map<Class<?>, Logger> loggers = newHashMap();

    /** Flag indicating initialization is complete. */
    private static boolean initialized;

     */
    @Override
    protected int writeBytesWireFormat(final byte[] dst, final int dstIndex) {
        return 0;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.internal.smb2.ServerMessageBlock2#readBytesWireFormat(byte[], int)
     */
    @Override
    protected int readBytesWireFormat(final byte[] buffer, int bufferIndex) throws SMBProtocolDecodingException {

     * and values are document counts for each query.
     */
    protected Map<String, Long> queryCountMap = new LinkedHashMap<>();

    /**
     * List of field facets containing aggregated field values and their counts.
     */
    protected List<Field> fieldList = new ArrayList<>();

    /**
     * Constructs a FacetResponse from OpenSearch aggregations.

    /** System helper for common system operations and utilities. */
    @Resource
    protected SystemHelper systemHelper;

    /** Behavior class for user information database operations. */
    @Resource
    protected UserInfoBhv userInfoBhv;

    /** Behavior class for favorite log database operations. */
    @Resource
    protected FavoriteLogBhv favoriteLogBhv;

    /** Configuration settings for the Fess search system. */

 *
 * {@snippet :
 * class CrawlingService extends AbstractScheduledService {
 *   private Set<Uri> visited;
 *   private Queue<Uri> toCrawl;
 *   protected void startUp() throws Exception {
 *     toCrawl = readStartingUris();
 *   }
 *
 *   protected void runOneIteration() throws Exception {
 *     Uri uri = toCrawl.remove();
 *     Collection<Uri> newUris = crawl(uri);
 *     visited.add(uri);