public static String[] getFilterNames() {
        synchronized (instance.filters) {
            String[] filterNames = new String[instance.filters.keySet().size()];
            instance.filters.keySet().toArray(filterNames);
            return filterNames;
        }
    }
Get the names of the defined filters.

@return Returns an array containing the names of filters that
have been registered.
logserver/src/main/java/com/yahoo/logserver/filter/LogFilterManager.java