ActsPropStepRootWriterSvc Node1 ActsPropStepRootWriterSvc - m_queue - m_writeMutex - m_writeThread - m_doEnd - m_filePath - m_treeName - m_outputFile - m_outputTree - m_eventNum - m_s_pX and 8 more... + initialize() + finalize() + ActsPropStepRootWriterSvc() + write() - writeThread() - doWrite() - end() Node2 extends< AthService, IActsPropStepRootWriterSvc > Node2->Node1