protected int defaultMaximumAllowedCharacter() {
        String encoding = format.getEncoding();
        if (encoding != null) {
            if (encoding.equals("US-ASCII")) {
                return 127;
            }
        }
        // no encoding for things like ISO-*, UTF-8 or UTF-16
        return -1;
    }
Returns the maximum allowed character code that should be allowed
unescaped which defaults to 127 in US-ASCII (7 bit) or
255 in ISO-* (8 bit).
@return the maximum allow character code
xmppserver/src/main/java/org/jivesoftware/util/XMLWriter.java