protected void collectSuites() {
   if (this.extToInfo == null) {
     for (IModelChangeProvider provider : listentingTo) provider.removeModelChangedListener(this);
     listentingTo.clear();
     this.extToInfo = Maps.newHashMap();
     IPluginModelBase xpect = PluginRegistry.findModel("org.xpect");
     collectSuites(xpect, Sets.<String>newHashSet());
   }
 }