@SuppressWarnings("unchecked")
    private HashSet<String> getPagedGroupNamesFromCache(final int startIndex, final int numResults) {
        return (HashSet<String>)groupMetaCache.get(getPagedGroupNameKey(startIndex, numResults).toString());
    }
Updates the caches maintained by this manager and dispatches events that reflect a group having all of its
properties removed.

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

@param group The group that was modified.
@param originalProperties The properties of the group prior to the removal.
xmppserver/src/main/java/org/jivesoftware/openfire/group/GroupManager.java