public final Set<scrum.server.release.Release> getParentReleases() { if (parentReleasesCache == null) { parentReleasesCache = new HashSet<scrum.server.release.Release>(); for (Release e : getEntities()) { if (e.isParentReleaseSet()) parentReleasesCache.add(e.getParentRelease()); } } return parentReleasesCache; }