private static int compressEdge(int nodeId, GraphEdgeType edgeType) {
    assert nodeId == NULL_ID || (nodeId < MAX_NODE_ID && nodeId > MIN_NODE_ID);
    int type = edgeType.ordinal();
    return (type << EDGE_BITS_OFFSET) | (COMPRESSED_NODE_ID_MASK & nodeId);
  }
private static int compressEdge(int nodeId, GraphEdgeType edgeType)