private void addWrapperPrefixMapping(final String prefix, final String uri) {
        LOGGER.trace("Storing prefix mapping {}:{}, map contains {}", prefix, uri, prefixToUriMap);
        prefixToUriMap.putIfAbsent(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