public String computeIfAbsent(final String key, final Function<String, String> mappingFunction) {
        return map.computeIfAbsent(new CIString(key), k -> mappingFunction.apply(k.key));
    }
String hash map that does not care about key case.
stroom-meta/stroom-meta-api/src/main/java/stroom/meta/api/CIStringHashMap.java