private Set<String> findAllGraphics(WorkspaceInfo ws) throws IOException {
final Catalog cat = geoServer.getCatalog();
final Set<String> externalGraphics = new HashSet<String>();
ws.accept( new CatalogVisitorAdapter() {
@Override
public void visit(WorkspaceInfo workspace) {
for( StoreInfo store : cat.getStoresByWorkspace(workspace,StoreInfo.class)){
try {
store.accept(this);