public Collection<String> getGlobalTileIDs(JcrSession session) {
AbstractContainer globalContainer = getGlobalContainer(session);
Set<String> result;
if (globalContainer != null) {
result = new HashSet<String>();
for (BrixNode n : globalContainer.tiles().getTileNodes()) {
String id = TileContainerFacet.getTileId(n);
if (!Strings.isEmpty(id)) {
result.add(id);
}
}