private @Nullable Iterator<? extends Iterator<? extends T>> getTopMetaIterator() {
      while (topMetaIterator == null || !topMetaIterator.hasNext()) {
        if (metaIterators != null && !metaIterators.isEmpty()) {
          topMetaIterator = metaIterators.removeFirst();
        } else {
          return null;
        }
      }
      return topMetaIterator;

        cl.delegate = builder
        cl.call()
        def firstChild = parent.getFirstChild()
        builder.elements.each { element ->
            parent.insertBefore(element, firstChild)
        }
    }

    public static void addBefore(Node sibling, Closure cl) {
        DomBuilder builder = new DomBuilder(sibling.ownerDocument, null)
        cl.delegate = builder

    }

    private static Class<?>[] toClassArray(final Object... methodArgs) {
        if (methodArgs == null) {
            return null;
        }
        final Class<?>[] result = new Class[methodArgs.length];
        for (int i = 0; i < methodArgs.length; ++i) {
            if (methodArgs[i] != null) {
                result[i] = methodArgs[i].getClass();
            }
        }
        return result;
    }

    }

    /**
     * A method that wraps the exception handling of {@link ZipInputStream#getNextEntry()}.
     *
     * @param zis
     *            {@link ZipInputStream}. Must not be {@literal null}.
     * @return {@link ZipEntry}
     * @see ZipInputStream#getNextEntry()
     */
    public static ZipEntry getNextEntry(final ZipInputStream zis) {
        assertArgumentNotNull("zis", zis);

        try {

                    + execution.getGoal());
            buffer.a(' ').strong('(' + execution.getExecutionId() + ')');
        }

        if (project != null) {
            buffer.a(" on project ");
            buffer.project(project.getArtifactId());
        }

        if (cause != null) {
            buffer.a(": ").failure(cause.getMessage());
        }

        return buffer.toString();
    }

   *
   * <p>It's acceptable for the underlying multimap to contain null keys, and even null values
   * provided that the function is capable of accepting null input. The transformed multimap might
   * contain null values, if the function sometimes gives a null result.
   *
   * <p>The returned multimap is not thread-safe or serializable, even if the underlying multimap

   *
   * <p>It's acceptable for the underlying multimap to contain null keys, and even null values
   * provided that the function is capable of accepting null input. The transformed multimap might
   * contain null values, if the function sometimes gives a null result.
   *
   * <p>The returned multimap is not thread-safe or serializable, even if the underlying multimap

    }

    // advance

    @Override
    public int getStartPosition() {
        if (start == null) {
            start = ComponentUtil.getFessConfig().getPagingSearchPageStartAsInteger();
        }
        return start;
    }

    @Override
    public int getOffset() {
        if (offset == null) {
            offset = 0;
        }
        return offset;
    }

    @Override

     * @return true if the document matches the expression, false otherwise
     */
    public boolean match(final Map<String, Object> map) {

        if (map == null || map.isEmpty() || matchExpression == null) {
            return false;
        }

        final Object value = ComponentUtil.getScriptEngineFactory().getScriptEngine(scriptType).evaluate(matchExpression, map);

        final WebAuthenticationConfig config = new WebAuthenticationConfig();

        // host/port/realm: only set if not blank (null means "any" - AuthScope.ANY equivalent)
        if (StringUtil.isNotBlank(getHostname())) {
            config.setHost(getHostname());
        }
        if (getPort() != null) {
            config.setPort(getPort());
        }
        if (StringUtil.isNotBlank(getAuthRealm())) {