Re: [featuremodel-dev] Variability

[Holger Papajewski <holger.papajewski@xxxxxxxxxxxxxxxx>]

Hello again,

by using upper and lower, you can express more than the usual variability types. So you
can have a feature group, where the user has to select at least 3 features but maximal 6
features. The classic variability types of FODA feature models are mapped:

MANDATORY    lower=-1, upper=-1  -> means all
ALTERNATIVE  lower=1,  upper=1   -> means exact one
OPTIONAL     lower=0,  upper=-1  -> any from zero to all
OR           lower=1;  upper=-1  -> at least one

(-1 stays for size of group => all)

Because OR matches best with "select at least 3 but not more than 6", we return OR for
this kind of groups.

I hope this helps,
  Holger


Am 21.10.2010 17:17, schrieb Andreas Graf:
>  Hi Holger,
> 
> thanks. I found the code in the implementation classes. I would like to ask, what is the
> semantics of upper and lower?
> In the code there is the comparisons of upper and lower to various combinations of -1,0
> and 1.
> 
>  } else {
>         type = VariabilityType.OR;
>       }
> 
> Would setting lower to 4 and upper to 10 a valid combination? And what would it mean? Why
> did you decide to define variability by means of to ints instead of an enumeration?
> 
> Thanks for the info!
> 
> Andreas
> 
> 
>> Hallo Andreas,
>>
>> that is right. The reason is quit simple. The variability is defined by the semantic of
>> the group to which a feature belongs. A feature is an alternative feature because it is
>> part of a group of features from which exactly one feature has to be selected. The
>> variability method is only a shortcut and easier to understand:
>>
>>    feature.getVariabilityType() == ALTERNATIVE
>>
>>    vs.
>>
>>    feature.getParentGroup().getLower() == 1&&  feature.getParentGroup().getUpper() == 1
>>
>>
>> Best regards,
>>    Holger
>>
>> Am 21.10.2010 16:57, schrieb Andreas Graf:
>>>   Hello,
>>>
>>> ok, I see that the variability is actually reflected by the values of upper and lower in
>>> the parent group. Is there an information about the rationale behind this design?
>>>
>>> Thanks,
>>>
>>> Andreas
>>>
>>>
>>>>   Hello,
>>>>
>>>> I was wondering why variability is reflected as a method in Feature, but not as an
>>>> attribute?
>>>>
>>>> Best Regards,
>>>>
>>>> Andreas
>>>>
>>>
>>
> 
> 


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