@Override
    public Collection<String> search(String key, String value) {
        LOG.info("Search groups on attributes not implemented yet");
        return Collections.emptyList();
    }
@see org.jivesoftware.openfire.group.AbstractGroupProvider#search(java.lang.String, java.lang.String)
xmppserver/src/main/java/org/jivesoftware/openfire/crowd/CrowdGroupProvider.java