private void verifyLong(String id, Long val) {
        LongDef def = longDefs.get(id);
        if (def == null)
            throw new IllegalArgumentException("No such long in " + verifyWarning(id));
        if (val == null) return;
        if (def.getMin() != null && val < def.getMin())
            failTooSmall(val, def.getMin(), name, id);
        if (def.getMax() != null && val > def.getMax())
            failTooBig(val, def.getMax(), name, id);
    }
Throws if the given value is not legal.
config/src/main/java/com/yahoo/vespa/config/ConfigDefinition.java