SysML 1.3 Aggregation

[SRX]

Hello Forum,

by experiments i found that an aggregation in SysML 1.3 bbd leads to a "property" instead of "parts" like read i literature and found when i use SysML 1.2. Is this a bug or a feature? Maybe i misunderstood something?


Thankx for reading (and answer)!

[Helmut Ortmann]

Hi,

in SysML 1.3 only properties with different stereotypes exist. The property <<ParticipantProperty>> is equal the former part. Parts don't exists in SysML 1.3.

Just drag the <<ParticipantProperty>> from toolbox to the internal block diagram.

If you have the wrong property type set or reset:
- <<ParticipantProperty>>
- isReference = true (advanced properties), if you have a reference
- isReference = false (advanced properties), if it's the original/defining part/property

The EA behavior of auto generating the correct <<stereotyp>>, isReferenced by drag&drop and composition isn't always what you would expect. But by simply correcting <<stereotype>>,IsReference you have a work araund.

Kind regards,

Helmut

[RobCDeJong]

Hi,

I do not agree with Helmut, see SysML 1.3 page 54.

A block can have different type of properties:

* reference properties (modeled via part association)
* part properties (modeled via shared association)
* values
* types

As far as the ParticipantProperty, this is used within an association class, see SysML 1.3 spec, page 58.

[Helmut Ortmann]

Hi,

@RobCDeJong
thanks for clarification. I wasn't correct.  In the following I try to explain it for EA.

according to SysML 1.3 page 65 a property may have the stereotypes:

• <<DistributedProperty>>
• <<ParticipantProperty>>
• <<ConnectorProperty>>
• <<>> No Stereotype it's simply a property

In my opinion the compartments 'parts' and 'references' express the usage of the property (page 54). In EA this is "isReference=true/false" of the property.

In EA:

• If you use an Association or Reference Association 'isReference' of the Property is true. It's visualized in the reference compartment.
• If you use a Composition or PartAssociation 'isReference' of the property is false. It's visualized in the properties compartment. In my opinion this isn't according to SysML 1.3

In my opinion there is no explicit Property of type part (it's in fact a compartment and the kind of usage).

I agree that the <<ParticipantProperty>> is part of an association class (thanks for your advice).

I hope that was it. Please check once more with your expertise.

Thanks,

Helmut

[rothnic]

Hi,

I do not agree with Helmut, see SysML 1.3 page 54.

A block can have different type of properties:

* reference properties (modeled via part association)
* part properties (modeled via shared association)
* values
* types

As far as the ParticipantProperty, this is used within an association class, see SysML 1.3 spec, page 58.

This is from the spec

"SysML establishes four basic classifications of properties belonging to a SysML Block or ValueType. A property typed by a SysML Block that has composite aggregation is classified as a part property, except for the special case of a constraint property. Constraint properties are further defined in Clause 10, “Constraint Blocks.” A port is another category of property, as further defined in Clause 9, “Ports and Flows.” A property typed by a Block that does not have composite aggregation is classified as a reference property. A property typed by a SysML ValueType is classified as a value property, and always has composite aggregation. Part, reference, value, and constraint properties may be shown in block definition compartments with the labels “parts,” “references,” “values,” and “constraints” respectively. Properties of any type may be shown in a “properties” compartment or in additional compartments with user-defined labels."

So in regard to your list, I believe the way that EA shows the associations makes this confusing. It should be that either shared(aggregation) or reference associations are reference properties. Part association, aka composition, is a part property.

I have not been able to find a way for the value property to work as stated above. When you type a property by a valuetype, the compartment does not change to value because the it doesn't seem to be reflected as a value property.