public void deleteGroupPostProcess(@Nonnull final Group group)
    {
        // Add a no-hit to the cache.
        groupCache.put(group.getName(), CacheableOptional.of(null));
        clearGroupNameCache();
        clearGroupCountCache();
        evictCachedUsersForGroup(group);
        evictCachedPaginatedGroupNames();
    }
Updates the caches maintained by this manager to reflect an existing group having been deleted.

This method is intended to be invoked to update the internal state of GroupManager after a group has been
deleted. It should rarely be invoked by code that is not part of the GroupManager implementation.

@param group The group that has been deleted. Care should be taken to not apply changes to this instance, as it
             no longer refers to a valid, existing group.
xmppserver/src/main/java/org/jivesoftware/openfire/group/GroupManager.java