can statechart diagram have decision point ?

[kevin ou]

Hi,

I would like to know that if a stateChart diagram can have a decision point as well as activity diagram. I try to use Rose to create StateChart diagram but found only Activity diagram can draw the decision point.
Thx.

Kevin

[somkiat puisungnoen]

In StateChart Diagram, you can use dicision point.

But i'm not use Rose, i'm using Posidon and ArgoUML Tool.

[Ilja Preuss]

That's a general complaint about all the "high-end" UML tools I know - they are often astonishingly inflexible. I know many developers who still call MS Visio the best "UML tool" out there, and I don't think that's unreasonable.

[Mani Ram]

You can use decision points in Statechart diagram.
To do this in Rational Rose:
Right click on the Toolbar (which displays various icons like State, State Transition etc), click "Customize...", select "Create a decision" from the "Available toolbar buttons" and "Add" it to the "Current toolbar buttons"
After that the decision tool will be available in the toolbar for you to use.


[ October 27, 2004: Message edited by: Mani Ram ]

[Bipin Patwardhan]

According to UML, Statechart diagrams cannot have an explicitly depicted condition as is usually done in an Activity diagram. It might be possible to do so in many UML tools as UML itself defines an activity diagram as a specialised form of the statechart diagram.

In case you want to depict some condition, show the condition in suqare brackets and put it on top of the transition arrow.

[Mani Ram]

Originally posted by Bipin Patwardhan:
According to UML, Statechart diagrams cannot have an explicitly depicted condition as is usually done in an Activity diagram.

From the UML Notation Guide (page 159)

A state diagram (and by derivation an activity diagram) expresses a decision when guard conditions are used to indicate different possible transitions that depend on Boolean conditions of the owning object.
...
...
The icon provided for a decision is the traditional diamond shape, with one incoming arrow and with two or more outgoing arrows, each labeled by a distinct guard condition with no event trigger.

[kevin ou]

Thank you for all the inputs

Kevin

[Scott Ambler]

You might find my overview of StateChart diagrams posted at http://www.agilemodeling.com/artifacts/stateMachineDiagram.htm to be of use. Decisions can be implied by the guards on transition lines, there are many examples posted at this page.

You might also find my style guidelines posted at http://www.agilemodeling.com/style/stateChartDiagram.htm to be of interest too.

BTW, in UML 1 Activity diagrams were specializations of state chart diagrams. In UML 2 they are not.

Also, in UML 2 state chart diagrams are now called State Machine Diagrams. Sigh.

- Scott