@Nonnull @ReturnsMutableCopy public Set<String> getAllRelatedNodeIDs() { final Set<String> ret = new LinkedHashSet<String>(); if (m_aIncoming != null) for (final IDirectedGraphRelation aRelation : m_aIncoming.values()) ret.add(aRelation.getFromID()); if (m_aOutgoing != null) for (final IDirectedGraphRelation aRelation : m_aOutgoing.values()) ret.add(aRelation.getToID()); return ret; }