core/src/main/java/com/digitalpebble/stormcrawler/bolt/SiteMapParserBolt.java
private final boolean sniff(byte[] content) {
        byte[] beginning = content;
        if (content.length > maxOffsetGuess && maxOffsetGuess > 0) {
            beginning = Arrays.copyOfRange(content, 0, maxOffsetGuess);
        }
        int position = Bytes.indexOf(beginning, clue);
        if (position != -1) {
            return true;
        }
        return false;
    }
private final boolean sniff(byte[] content) {
        byte[] beginning = content;
        if (content.length > maxOffsetGuess && maxOffsetGuess > 0) {
            beginning = Arrays.copyOfRange(content, 0, maxOffsetGuess);
        }
        int position = Bytes.indexOf(beginning, clue);
        if (position != -1) {
            return true;
        }
        return false;
    }
Examines the first bytes of the content for a clue of whether this
document is a sitemap, based on namespaces. Works for XML and
non-compressed documents only.