Question on Activity Diagrams

[objectinfo]

Suppose I have two activity diagrams:

ad1 -> containing Activity1 and Acvitity2
ad2 -> containing Activity3 and Activity4.

Scenario 1:
Now, in ad2, if, from the project browser, I drag the diagram ad1 and put it in ad2 (and chose the 'Hyperlink' option), then in ad2, I will see the 'Structured activity' ad1 (with the bow-tie symbol). If now I double-click on ad1, it will open up the diagram ad1.


Scenario 2:
In the diagram ad2, from the project browser, I drag and drop the Activity1 and choose the 'as invocation of Activity (Action)' option. In this case, a rectangle appears in the ad2 diagram with the name ':Activity1' and this rectangle has the 'rake' symbol on it.

My Questions are:
1. What is the difference between the two scenarios above?
2. My understanding was that in UML, the 'rake' symbol was for designating an activity which has sub-activities. Is this right?
3. And then, what is the bow-tie symbol for
4. Is the name 'bow-tie' the right name I am using, or does it have any other official name?

[objectinfo]

Please can somebody help me on this.

[KP]

OK, answering your questions in reverse order:

4. The bow tie symbol is actually supposed to look like 3 links of a chain.

3. It isn't a UML symbol, it's an EA symbol used to denote that the element has a link to a child diagram. Double-click the element and the child diagram will be opened. The child diagram shows the detail of its owner.

2. The rake symbol represents an invocation of an Activity, i.e. it's a CallBehaviorAction.

1. The Activity defines the behaviour; the CallBehaviorAction behaves.

Hope that makes sense; not sure that I've described it very well.

[objectinfo]

Hi KP,
Thanks for the response.


Regarding your point:
<quote>
The rake symbol represents an invocation of an Activity, i.e. it's a CallBehaviorAction
</quote>

Isn't the rake symbol a standard symbol in UML to show that that activity has sub-activities?

[KP]

The official word (UML 2.2 Superstructure, section 12.3.14):

"The call of an activity is indicated by placing a rake-style symbol within the symbol. The rake resembles a miniature hierarchy, indicating that this invocation starts another activity that represents a further decomposition."