protected ExtractReader buildExtractReader(Map<String, String> localAttrs) {
        long minExtractLength = PropsUtil.getLong(localAttrs.get("minExtractLength"), -1L);
        long maxExtractLength = PropsUtil.getLong(localAttrs.get("maxExtractLength"), -1L);

        ExtractReader.ALTER_METADATA_LIST alterExtractList = getAlterMetadata(localAttrs);
        return new ExtractReader(alterExtractList, minExtractLength, maxExtractLength);
    }
@return the main tables, not including the ref tables
tika-eval/tika-eval-app/src/main/java/org/apache/tika/eval/app/batch/EvalConsumerBuilder.java