private <T> void mergeValue(final Supplier<T> getter, final Consumer<T> setter) {
        T value = getter.get();
        if (value != null) {
            setter.accept(value);
        }
    }
Shallow merge of the two Purpose objects
stroom-event-logging/stroom-event-logging-impl/src/main/java/stroom/event/logging/impl/StroomEventLoggingServiceImpl.java