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QVTo constructor behavior when extending transformations [message #1688375]

Fri, 20 March 2015 15:20

Teun van de Berg

Messages: 12
Registered: October 2014

Junior Member

Hi,

I observed the following behavior for constructors, which I didn't expect:

I have two transformations A, and B. B extends A. A contains a constructor (ConsA). A also contains a mapping which uses ConsA (mappingA). I intended to overwrite this constructor in B and hence added a new implementation of ConsA in B. B utilizes mappingA. Much to my surprise the constructor from A is called rather from B. If I surround the constructor in a mapping which I also overwrite in transformation B the new constructor is used.

In pseudo code:

transformation A();
...
mapping mappingA()
{
 new ConsA();
}
ConsA::ConsA(inp:String) // The to be created object is named ConsA for this example.
{
 log("Constructor from mapping A");
}


transformation B() extends transformation A();
...
mapping X()
{
 map mappingA();
}
ConsA::ConsA(inp:String) // The to be created typeis named ConsA for this example.
{
  log("Constructor from mapping B");
}

Logs: Constructor from mapping A.

Overwriting mappingA in transformation B will result in: Constructor from mapping B.

The QVTo spec states:
Quote:

1) A constructor may be defined as an operation of the class to be constructed or may be owned by a module that plays a role of factory for the class.
2) An access import behaves as a traditional package import, whereas extension semantics combines package import and class inheritance paradigm.

Is the current behavior correct? Can I make my constructor be owned by the class rather than the module?

Kind regards,
Teun

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Re: QVTo constructor behavior when extending transformations [message #1688390 is a reply to message #1688375]

Fri, 20 March 2015 15:45

Ed Willink

Messages: 7655
Registered: July 2009

Senior Member

Hi

Please use the qvto newsgroup for QVTo discussions.

In this case please raise a Bugzilla.

Regards

Ed Willink

On 20/03/2015 15:20, Teun van de Berg wrote:
> Hi,
>
>
> I observed the following behavior for constructors, which I didn't
> expect:
>
> I have two transformations A, and B. B extends A. A contains a
> constructor (ConsA). A also contains a mapping which uses ConsA
> (mappingA). I intended to overwrite this constructor in B and hence
> added a new implementation of ConsA in B. B utilizes mappingA. Much to
> my surprise the constructor from A is called rather from B. If I
> surround the constructor in a mapping which I also overwrite in
> transformation B the new constructor is used.
>
> In pseudo code:
>
> transformation A();
> ..
> mapping mappingA()
> {
> new ConsA();
> }
> ConsA::ConsA(inp:String) // The to be created object is named ConsA
> for this example.
> {
> log("Constructor from mapping A");
> }
>
>
> transformation B() extends transformation A();
> ..
> mapping X()
> {
> map mappingA();
> }
> ConsA::ConsA(inp:String) // The to be created typeis named ConsA for
> this example.
> {
> log("Constructor from mapping B");
> }
>
> Logs: Constructor from mapping A.
>
> Overwriting mappingA in transformation B will result in: Constructor
> from mapping B.
>
> The QVTo spec states:
> Quote:
>> 1) A constructor may be defined as an operation of the class to be
>> constructed or may be owned by a module that plays a role of factory
>> for the class. 2) An access import behaves as a traditional package
>> import, whereas extension semantics combines package import and class
>> inheritance paradigm.
>
>
> Is the current behavior correct? Can I make my constructor be owned by
> the class rather than the module?
>
>
> Kind regards,
> Teun

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