@SuppressWarnings("deprecation")
    @Override
    public void processingInstruction(String target, String data)
            throws SAXException {
        flush();
        if (!target.isEmpty() && startsWithComposingChar(target)) {
            warn("Processing instruction target starts with a composing character.");
        }
        if (!data.isEmpty()) {
            if (startsWithComposingChar(data)) {
                warn("Processing instruction data starts with a composing character.");
            } else if (!Normalizer.isNormalized(data, Normalizer.NFC, 0)) {
                warn("Processing instruction data in not in Unicode Normalization Form C.");
            }
        }
    }
@see nu.validator.checker.Checker#processingInstruction(java.lang.String,
     java.lang.String)
src/nu/validator/checker/NormalizationChecker.java