LArRodIdHash Node1 LArRodIdHash - m_size - m_offset + initialize() + operator()() + max() + identifier() + offset() Node2 std::map< unsigned int, int > + keys + elements Node2->Node1 -m_lookup Node3 std::vector< ID > Node3->Node1 -m_int2id Node4 std::vector< T > Node4->Node3 +elements Node5 T Node5->Node4 +elements