public int getSortOrder() {
        return this.sortOrder;
    }
Returns the sort order, which will be {@link #ASCENDING} for ascending sorting, or {@link #DESCENDING} for
descending sorting. The default value is {@link #ASCENDING}.

Descending sorting is: 3, 2, 1, etc. Ascending sorting is 1, 2, 3, etc.

@return the sort order.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/PubsubNodeResultFilter.java