private BufferedReader getReader(Path inputFile) throws IOException {
        InputStream is = Files.newInputStream(inputFile);
        if (inputFile
                .toString()
                .endsWith(".gz")) {
            is = new GzipCompressorInputStream(is);
        }
        return new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8));
    }
Utility class that reads in a UTF-8 input file with one document per row
and outputs the 20000 tokens with the highest document frequencies.
<p>
The CommmonTokensAnalyzer intentionally drops tokens shorter than 4 characters,
but includes bigrams for cjk.
<p>
It also has a include list for __email__ and __url__ and a skip list
for common html markup terms.
tika-eval/tika-eval-app/src/main/java/org/apache/tika/eval/app/tools/TopCommonTokenCounter.java