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[Acceleo] Direct access to the elements in a Collection or Sequence [message #714057]

Tue, 09 August 2011 17:46

Tomas Balderas

Messages: 64
Registered: July 2010

Member

Hello

I am looking for an operation that returns the n-th element in a Sequence (or Collection if it is possible). I am transforming activity diagrams to source code and need to generate source code statements that use the name of the object flow edges incoming to an action's input pins. I am restricting every action to have only two input pins. Therefore, iterating over the collection of two input pins of an action is not convenient. The most readable solution to me is to directly access the instances of InputPin in the collection of input pins of every action.

Does anybody know how to directly access the elements in a collection (or sequence)? I looked for an operation in Accleo's Operation Reference and in the OCL specification and cannot find it. I think there should be support for this kind of access since I think it is a common requirement.

Thanks. Kindest regards.

/TB

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Re: [Acceleo] Direct access to the elements in a Collection or Sequence [message #714064 is a reply to message #714057]

Tue, 09 August 2011 17:53

Ed Willink

Messages: 7465
Registered: July 2009

Senior Member

Hi

I think you want Sequence::at() or OrderedSet::at()

You can loop (in OCL and not that differently in Acceleo) with an index
counter as

Sequence{1..collection->size()}->forAll(i : Integer | collection->at(i)
.....)

Regards

Ed Willink

On 09/08/2011 18:46, Balderas wrote:
> Hello
>
> I am looking for an operation that returns the n-th element in a
> Sequence (or Collection if it is possible). I am transforming activity
> diagrams to source code and need to generate source code statements
> that use the name of the object flow edges incoming to an action's
> input pins. I am restricting every action to have only two input pins.
> Therefore, iterating over the collection of two input pins of an
> action is not convenient. The most readable solution to me is to
> directly access the instances of InputPin in the collection of input
> pins of every action.
>
> Does anybody know how to directly access the elements in a collection
> (or sequence)? I looked for an operation in Accleo's Operation
> Reference and in the OCL specification and cannot find it. I think
> there should be support for this kind of access since I think it is a
> common requirement.
>
> Thanks. Kindest regards.

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Re: [Acceleo] Direct access to the elements in a Collection or Sequence [message #714263 is a reply to message #714064]

Wed, 10 August 2011 07:19

Laurent Goubet

Messages: 1897
Registered: July 2009

Senior Member

Hi,

Ed has answered perfectly, I only want to add that the "at(int)" method is only available for ordered collections. If you set the reference as "unordered" in your metamodel, you'll have to cast the collection to an ordered type prior to access it (with the potential randomness of the reordering it involves). These methods are not Acceleo methods, thus the correct place to find them was in the OCL operation reference for Sequence or OrderedSet.

The cast to ordered collections is done through "asSequence" or "asOrderedSet" :

-----
inputPins->asSequence()->at(1)
-----

Laurent Goubet
Obeo

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Re: [Acceleo] Direct access to the elements in a Collection or Sequence [message #714287 is a reply to message #714263]

Wed, 10 August 2011 08:35

Ed Willink

Messages: 7465
Registered: July 2009

Senior Member

Hi

As of Indigo, Eclipse OCL has its own library documentation
(auto-generated from the library model by Acceleo).

See
http://help.eclipse.org/indigo/topic/org.eclipse.ocl.doc/help/StandardLibrary.html
or the OCL Documentation in the Help Contents.

Regards

Ed Willink

On 10/08/2011 08:19, Laurent Goubet wrote:
> Hi,
>
> Ed has answered perfectly, I only want to add that the "at(int)"
> method is only available for ordered collections. If you set the
> reference as "unordered" in your metamodel, you'll have to cast the
> collection to an ordered type prior to access it (with the potential
> randomness of the reordering it involves). These methods are not
> Acceleo methods, thus the correct place to find them was in the OCL
> operation reference for
> http://wiki.eclipse.org/Acceleo/OCL_Operations_Reference#at_.28_index_:_Integer_.29_:_T
> or
> http://wiki.eclipse.org/Acceleo/OCL_Operations_Reference#at_.28_index_:_Integer_.29_:_T_2.
>
> The cast to ordered collections is done through "asSequence" or
> "asOrderedSet" :
>
> -----
> inputPins->asSequence()->at(1)
> -----
>
> Laurent Goubet
> Obeo

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