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(no subject) [message #687177]

Sat, 11 June 2011 09:05

John Smith

Messages: 137
Registered: July 2009

Senior Member

Is it possible to model an enumeration, where actually <code>null</code>
shall be returned for an attribute having this enumeration type, if no
value is set to the attribute before?

So I want a behavior like EBooleanObject is for EBoolean.

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(no subject) [message #687179 is a reply to message #687177]

Sat, 11 June 2011 10:03

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

Enumerations always have a value, but Features can have optional
multiplicity so why not just use lowerBound=0 ?

Regards

Ed Willink

On 11/06/2011 10:05, exquisitus wrote:
> Is it possible to model an enumeration, where actually
> <code>null</code> shall be returned for an attribute having this
> enumeration type, if no value is set to the attribute before?
>
> So I want a behavior like EBooleanObject is for EBoolean.

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(no subject) [message #687180 is a reply to message #687177]

Sat, 11 June 2011 16:25

Ed Merks

Messages: 33139
Registered: July 2009

Senior Member

Yes, you can define an EDataType whose instance type name is the fully
qualified name of the generated enum and use that instead of the EEnum.

exquisitus wrote:
> Is it possible to model an enumeration, where actually
> <code>null</code> shall be returned for an attribute having this
> enumeration type, if no value is set to the attribute before?
>
> So I want a behavior like EBooleanObject is for EBoolean.

Ed Merks
Professional Support: https://www.macromodeling.com/

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(no subject) [message #687182 is a reply to message #687179]

Sun, 12 June 2011 11:22

John Smith

Messages: 137
Registered: July 2009

Senior Member

> Enumerations always have a value, but Features can have optional
> multiplicity so why not just use lowerBound=0 ?
>
because even with lowerBound=0 and the feature is unset, I will get the
default value, and not null.

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(no subject) [message #687184 is a reply to message #687182]

Sun, 12 June 2011 12:45

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

Which is why you need to call eIsSet to distinguish the two cases.

Regards

Ed Willink

On 12/06/2011 12:22, exquisitus wrote:
>
>> Enumerations always have a value, but Features can have optional
>> multiplicity so why not just use lowerBound=0 ?
>>
> because even with lowerBound=0 and the feature is unset, I will get
> the default value, and not null.

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