private void fatalError(final CharBuffer sb) throws SAXException {
        final String message = sb.toString();
        sb.clear();

        final SAXParseException exception = new SAXParseException(message, locator);
        errorHandler.fatalError(exception);

        // If we aren't stepping then throw an exception to terminate early.
        if (!pipelineContext.isStepping()) {
            throw LoggedException.wrap(message, exception);
        }
    }
Sends characters to the current validator handler.

@param ch     Characters.
@param start  Start of char buffer.
@param length Number of chars to send.
@throws SAXException Not thrown.
@see stroom.pipeline.filter.AbstractXMLFilter#characters(char[],
int, int)
stroom-pipeline/src/main/java/stroom/pipeline/filter/SchemaFilter.java