Loop: running example using DecisionNode and MergeNode and an Integer property in a context

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

UML keywords

Activity Diagram

ReadStructuralFeatureAction

AddStructuralFeatureValueAction

CallBehaviorAction

Keywords

Slide kind

UML Activity Diagram

Apart from demonstrating DecisionNode and MergeNode used together to create a "manual" loop, this slide shows some additional aspects of Activity Diagrams and has some additional diagnostic outputs for the simulation (play also the mini video below):

Click on the image to view it full size

Watch simulation

One could of course side-step the fiddly use of ReadSelfAction ReadStructuralFeatureAction, and AddStructuralFeatureValueAction by using Action Language Helper (ALH) or Action Language for Foundational UML (Alf). Note that Magic Cyber-Systems Engineer ^® (Cameo Systems Modeler^®) is smart enough here to detect the attribute Property v in the guard v < 5 (so there's no need to use a decisionInputFlow or decisionInput Behavior on the DecisionNode).

For some simpler examples that use the Magic Model Analyst^® (Cameo Simulation Toolkit^®) popup value entry dialog and the fUML ReadLine CLI visit:

SysMLv1: A basic ControlFlow and DecisionNode loop with implied variable popup dialog [with mini video]

SysMLv1: A basic ControlFlow, ObjectFlow, and DecisionNode loop driven by fUML ReadLine CLI String input [with mini video]

Visit also: TIP/GOTCHA: SysMLv1/fUML: Cameo Simulation Toolkit: If you have a ControlFlow loop with a DecisionNode test you MUST have a MergeNode for the continuation path ControlFlow (typically entered also from an InitialNode or other loop starting point).

Visit also: TIP/GOTCHA: SysMLv1/UML: Cameo Simulation Toolkit: If you use a «decisionInputFlow» to a DecisionNode you MUST also have a ControlFlow to the DecisionNode; if you don't use an explicit «decisionInputFlow» you don't need the "extra" ControlFlow

Visit also: TIP: SysMLv1/UML: Cameo Simulation Toolkit: HOWTO convert an fUML ReadLine CLI String to a Boolean for cleaner DecisionNode tests against a LiteralBoolean [true] guard.

We'll see next how to use the dedicated (and somewhat dreaded) UML LoopNode structured action.

Up next

LoopNode: basic running example

Notes

[TIP]{OPTION} Not every task in Activity Diagrams is well-suited to graphical modelling and LoopNode and ConditionalNode are notoriously fiddly to setup; consider using Action Language Helper (ALH) or Action Language for Foundational UML (Alf)

Snippets (quotes/extracts)

Visit also

Visit also (backlinks)

TRAIL: SysMLv1/UML: Cameo Simulation Toolkit® (Magic Model Analyst®): Some basics for beginners and some more advanced cases [with mini videos]

TIP: SysMLv1/UML: Cameo Simulation Toolkit: HOWTO convert an fUML ReadLine CLI String to a Boolean for cleaner DecisionNode tests against a LiteralBoolean [true] guard.

TIP/GOTCHA: SysMLv1/fUML: Cameo Simulation Toolkit: If you have a ControlFlow loop with a DecisionNode test you MUST have a MergeNode for the continuation path ControlFlow (typically entered also from an InitialNode or other loop starting point).

TIP/GOTCHA: SysMLv1/UML: Cameo Simulation Toolkit: If you use a «decisionInputFlow» to a DecisionNode you MUST also have a ControlFlow to the DecisionNode; if you don't use an explicit «decisionInputFlow» you don't need the "extra" ControlFlow

Related slides (includes other tutorials)

Related slides (backlinks, includes other tutorials)

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