Collection<ProjectStructureElementUsage> (ProjectStructureElement selected) { ProjectStructureElement[] elements = myElementWithNotCalculatedUsages.toArray(new ProjectStructureElement[0]); for (ProjectStructureElement element : elements) { updateUsages(element, getUsagesInElement(element)); } final Collection<ProjectStructureElementUsage> usages = mySourceElement2Usages.get(selected); return usages != null ? usages : Collections.emptyList(); }