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check if profile property in empty

medini_1005899080

Hi,

I have a profile property on an "Element" from the type "Item". Now I want to check if this property is empty. I tried this:

self.user_item_derived_prop.oclAsType(hazard::PlainItem).name->oclIsInvalid()

but it is always "true", no matter if there is something in or not.

I tried also to go over the proxyModel:

self.user_item_derived_prop.oclAsType(projectmodel::PJProxyModel).originalModel.name->oclIsInvalid()

Both is not working.

What could be the problem?

Sven

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medini_1023909254

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medini_1024169437

Sven,

a few thoughts when looking at the OCL code.

Is this a 0..1 or 0..n property? If the first be careful when using -> it is not a collection, right?

The later shall not work, we dont store the proxy model there.

And you really mean oclIsInvalid and not oclIsUndefined?

Jan

medini_1005899080

Hi Jan,

It is a 1..n property (one ore more Items can be linked). I am not sure when it is a collection.

I tried oclInvalid and oclUndefined, both will not work.

When I just refere to the element "self.user_item_derived_prop" the property seems to be empty.

Sven

medini_1024169437

Thanks Sven,

that narrows the problem. Could you also give the version you use? I remember an issue we had in OCL handling of profile properties and some workaround for dedicated versions, proposing to use mediniXXX operations instead of directly accessing the property but that was only for one version.

Jan

medini_1005899080

Hi Jan,

I am using the 2023R2 Version. (Not 2.1)

Sven

medini_1024169437

Sven, I quickly tested with 2023 R2 and

self.user_items->isEmpty()

works for me to detect whether any item is set at the Element or not. I am not sure though whether that is your use case as you access the name attribute of the Items?

So before going on, could you explain what your script / OCL shall do? Maybe i just misunderstood

Jan

medini_1005899080

Hi Jan,

If I try this, the result is always "false".

What is the setup?:

I have on property "item derived prop" which is a property looking for a "traced" Element (self.mediniGetTracedElements(hazard::PlainItem,'cap')).

with the "testa" I am using the self.user_item_derived_prop->isEmpty().

Sven

medini_1024169437

Got it Sven, I had simply created a reference profile property. But you use a derived / scripted one. Will try to replicate and find the cause.

I vaguely remember now that scenario. Stay tuned.

Jan

medini_1024169437

Hi Sven,

I investigated a little bit and here is the reason for the observed behavior:

if an OCL expression is evaluated, and the result is a non-empty collection, it is returned as is
if the result is undefined or is an-empty collection, the default value of the property is returned instead
this is basically a string and the default-default is '', an empty string
if you now access ->isEmpty or ->size, so a collection function on a string, OCL will create a new collection with that string inside

So far the explanation, that explains why if you don't have any trace, you get an empty string.

Problem I faced: with OCL it is difficult to handle return values of different types. If you use = '' or .size() it will work with the string but fail with the list and vice versa. I am not sure yet how to write something like "if it is a string, do this test, if it is a list do that test". You may change the default value of the attribute to see that you get that returned though.

Maybe developing one of the properties in JavaScript will solve the issue. We cannot simply change the OCL contract to fix this i guess.

Jan

medini_1005899080

Hi Jan,

The background is: I want to have a m2Doc Report, but only if this attribute contains something.

m:if i.user_item_derived_prop.toString().size() = 0

This was my solution. In this case it works, in another case it does not work.

Sven

medini_1059007410

Hi Sven,

Oh, in M2Doc you are using AQL, not OCL. The difference is not too big, but Null handling is a prominent one (besides not having to cast to types with oclAsType()).

From the AQL documentation :

null handling

AQL handles null (OclVoid) differently from ocl, a null value will not cause a failure but will be silently handled.
For example, null.oclIsKindOf(ecore::EClass) would have returned true for MTL/OCL, forcing users to use not self.oclIsUndefined() and self.oclIsKindOf(ecore::EClass) instead. This is no longer true in AQL, where «null» doesn’t conform to any type, so null.oclIsKindOf(ecore::EClass) will return false. Note that it’s still possible to «cast» null in any given classifier. null.oclAsType(ecore::EClass) will not fail at runtime.

Furthermore oclIsUndefined() does not exist in AQL and should be replaced by a ... <> null expression.

So please try {m:if i.user_item_derived_prop <> null }.

Regards,

Nils

PS: In a webinar specifically known to you, have a look at position 30:00 ;-)

medini_1024169437

Nils, you comment is very valid, however, in this particular case, I think the OCL engine that calculates the profile property returns an empty string and not null or an empty list, that is the problem here. Maybe one option is to move the complete logic (I mean, self.mediniGetTracedElements(hazard::PlainItem,'cap') into the m2doc document and AQL instead of a profile property.

Happy Reporting

Jan

medini_1023909254

medini_1059007410

All,

I've found and used a workaround (as I needed to get "Top Level Effect" OCL property into my M2Doc report):

{ m:if var.user_ocl_property_giving_back_a_potentially_empty_collection->first() <> '' } ... { m:endif }

That works for me.

Regards,

Nils