@Override
    public void startPrefixMapping(final String prefix, final String uri) throws SAXException {
        super.startPrefixMapping(prefix, uri);
        LOGGER.trace("startPrefixMapping({}, {})", prefix, uri);

        if (insideValueElement) {
            recordHavingSeenXmlContent();
            fastInfosetStartPrefixMapping(prefix, uri);
        } else {
            // capture all the prefix mappings we encounter before we are in the value and hold them for use later
            addWrapperPrefixMapping(prefix, uri);
        }
    }
Sets the locator to use when reporting errors.

@param locator The locator to use.
stroom-state/stroom-planb-impl/src/main/java/stroom/planb/impl/pipeline/PlanBFilter.java