@Override
    public boolean isDeclared(String uri, String localName) {
        int index = getIndex(uri, localName);
        return isDeclared(index);
    }
@return false unless the attribute was declared in the DTD.
@throws java.lang.IllegalArgumentException
            When the supplied names do not identify an attribute.
src/nu/validator/gnu/xml/aelfred2/SAXDriver.java