long getSourceFileLength(List<Metadata> metadataList) {
        if (metadataList == null || metadataList.size() < 1) {
            return NON_EXISTENT_FILE_LENGTH;
        }
        return getSourceFileLength(metadataList.get(0));
    }
@param extractRootDir
@param relativeSourceFilePath
@return extractFile or null if couldn't find one.
tika-eval/tika-eval-app/src/main/java/org/apache/tika/eval/app/AbstractProfiler.java