public static void addLogFilter(String name, LogFilter filter) {
        if (filter == null) {
            throw new NullPointerException("filter cannot be null");
        }

        if (name == null) {
            throw new NullPointerException("name cannot be null");
        }

        String n = name.toLowerCase();

        if (n.startsWith("system.")) {
            throw new IllegalArgumentException("'system' namespace is reserved");
        }

        instance.addLogFilterInternal(n, filter);
    }
Public interface for adding a name-logfilter mapping. If
there exists a mapping already the old mapping is replaced
with the new mapping.
<p>
If the name is within the namespace reserved for internal
built-in filters it will throw an exception
logserver/src/main/java/com/yahoo/logserver/filter/LogFilterManager.java