IIOVDbMetaDataTool Node1 IIOVDbMetaDataTool + registerFolder() + registerFolder() + addPayload() + processInputFileMetaData() + findMetaDataContainer() + interfaceID() Node2 IMetaDataTool + beginInputFile() + endInputFile() + metaDataStop() + interfaceID() Node2->Node1 Node3 IAlgTool Node3->Node2 Node4 ILockableTool + lock_shared() + unlock_shared() Node4->Node1