Gallery Tutorial TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo Section 01:04: UML Behavior: Activities quick start Tags and keywords Topic level ESSENTIAL UML keywords Activity Activity Diagram InitialNode JoinNode ControlFlow Keywords simulation Magic Model Analyst [Cameo Simulation Toolkit] Slide kind UML Activity Diagram The use of a ForkNode after an InitialNode is one way to address the initialisation problem illustrated in the previous slide: Click on the image to view it full size Watch simulation video_sim We see in the next slide another option for handling this correctly, namely using two InitialNodes. Up next OPTION double InitialNode Notes Snippets (quotes/extracts) [UML-2.5.1] An InitialNode shall not have any incoming ActivityEdges, which means the InitialNodes owned by an Activity will always be enabled when the Activity begins execution and a single control token is placed on each such InitialNode when Activity execution sta [UML-2.5.1] The outgoing ActivityEdges of an InitialNode must all be ControlFlows. The control token placed on an InitialNode is offered concurrently on all outgoing ControlFlows. [UML-2.5.1] As an ActivityNode may be the source for multiple ActivityEdges, the same token can be offered to multiple targets. [UML-2.5.1] However, the same token can only be accepted at one target at a time (unless it is copied, whereupon it is not the same token, see ForkNodes ... and ExecutableNodes ...). [UML-2.5.1] If a token is offered to multiple ActivityNodes at the same time, it shall be accepted by at most one of them, but exactly which one is not completely determined by the Activity flow semantics. [UML-2.5.1] This means that an Activity model in which non-determinacy occurs may be subject to timing issues and race conditions. It is the responsibility of the modeler to avoid such conditions in the construction of the Activity model, if they are not desired. [UML-2.5.1] Tokens offered to a ForkNode are offered to all outgoing ActivityEdges of the node. If at least one of these offers is accepted, the offered tokens are removed from their original source and the acceptor receives a copy of the tokens. Visit also Visit also (backlinks) Related slides (includes other tutorials) Related slides (backlinks, includes other tutorials) OPTION double InitialNode ExecutableNode has implicit fork Flags Book traversal links for CORRECT InitialNode explicit fork Previous Up Next
