protected void processEmbeddedDocNames(final Map<String, PDComplexFileSpecification> embeddedFileNames, final StringWriter writer) {
        if (embeddedFileNames == null || embeddedFileNames.isEmpty()) {
            return;
        }

        for (final Map.Entry<String, PDComplexFileSpecification> ent : embeddedFileNames.entrySet()) {
            final PDComplexFileSpecification spec = ent.getValue();
            if (spec != null) {