Icon class icon_class fas fa-quote-left icon_class_computed fas fa-quote-left Related content Source Unified Modeling Language 2.5.1 Copyright information About Object Management Group copyright in text extracts quoted from OMG specifications for educational purposes Snippet kind SEMANTIC UML keywords Activity ActivityNode ExecutableNode Action ActivityNode::incoming ControlFlow Previous snippet Full quote ExecutableNodes actually carry out the desired behavior of an Activity. If an ExecutableNode has incoming ControlFlows, then there must be tokens offered on all these flows that it accepts before beginning execution. Next snippet Related snippets There are three kinds of ActivityNodes: ControlNodes act as “traffic switches” managing the flow of tokens across ActivityEdges. Tokens cannot “rest” at ControlNodes (with exceptions for InitialNodes and ForkNodes ...). ObjectNodes hold object tokens accepted from incoming ObjectFlows and may subsequently offer them to outgoing ObjectFlows (with a modeler-specified exception for ControlFlows, see isControlType for ObjectNodes ...). An ExecutableNode is an ActivityNode that carries out a substantive behavioral step of the Activity that contains it. An ExecutableNode may also consume and produce data, but it must do so through related ObjectNodes (Actions use Pins for this purpose ... While the ExecutableNode is executing, it is considered to hold a single control [token] indicating it is execution [executing]. Before an ExecutableNode begins executing, it accepts all tokens offered on incoming ControlFlows. If multiple tokens are being offered on a ControlFlow, they are all consumed. The values on such object tokens may be used to affect the control of ExecutableNodes that are the targets of such ControlFlows, though the specific meaning of such values is not defined in this specification An ExecutableNode shall not execute until all incoming ControlFlows (if any) are offering tokens. That is, there is an implicit join on the incoming Control Flows. Specific kinds of ExecutableNodes may have additional prerequisites ... There are two kinds of ActivityEdges: A ControlFlow is an ActivityEdge traversed by control tokens or object tokens of control type, which are use to control the execution of ExecutableNodes A ControlFlow is an ActivityEdge that only passes control tokens (and some object tokens as specified by modelers, see isControlType for ObjectNodes ...). ControlFlows are used to explicitly sequence execution of ActivityNodes, as the target ActivityNode cannot receive a control token and start execution until the source ActivityNode completes execution and produces the token. An ObjectFlow is an ActivityEdge that can have object tokens passing along it. ObjectFlows model the flow of values between ObjectNodes. Unlike ControlFlows, ObjectFlows also provide additional support for multicast/receive, token selection from ObjectNodes and transformation of tokens Related snippets (backlinks) Visit also Visit also (backlinks) Flags
