D3PD::IMetadataTool Node1 D3PD::IMetadataTool + DeclareInterfaceID() + writeMetadata() Node3 D3PD::LBMetadataTool - m_metakey + LBMetadataTool() + initialize() + queryInterface() + writeMetadata() Node1->Node3 Node2 IAlgTool Node2->Node1