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Defining 'equals'-operation on custom datatype [message #512955]

Mon, 08 February 2010 12:40

Messages: 19
Registered: October 2009
Location: Eindhoven, The Netherland...

Junior Member

Hi all,

I created a custom datatype to represent String, let's call it XString. I did this so that I could put a constraints on the allowed characters in the XString. So I added a datatype to my Ecore model, and set the Instance Class Name to java.lang.String

However, now I get an error when I want to compare XStrings:

Could find operation '==(Model::XString)' for type 'Model:XString'

While it is true that I did not define this operation, I kind of hoped it was implied by setting the instance class to java.lang.String. But apparently this is not the case.

So my question now is, what to do? Where do I define the equals operation? Or do I have to link my datatype to the standard String datatype in another way?

Thanks in advance,

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Re: Defining 'equals'-operation on custom datatype [message #512983 is a reply to message #512955]

Mon, 08 February 2010 13:46

Ed Merks

Messages: 33140
Registered: July 2009

Senior Member

RJ,

Comments below.

RJ wrote:
> Hi all,
>
> I created a custom datatype to represent String, let's call it
> XString. I did this so that I could put a constraints on the allowed
> characters in the XString. So I added a datatype to my Ecore model,
> and set the Instance Class Name to java.lang.String
>
> However, now I get an error when I want to compare XStrings:
>
> Could find operation '==(Model::XString)' for type 'Model:XString'
Where are you seeing this error?
>
>
> While it is true that I did not define this operation, I kind of hoped
> it was implied by setting the instance class to java.lang.String. But
> apparently this is not the case.
>
> So my question now is, what to do? Where do I define the equals
> operation? Or do I have to link my datatype to the standard String
> datatype in another way?
I get the sense this is an OCL question or belongs somewhere else. I
don't know how this issue arises purely with EMF itself...
>
> Thanks in advance,

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

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Re: Defining 'equals'-operation on custom datatype [message #513002 is a reply to message #512955]

Mon, 08 February 2010 14:46

Messages: 19
Registered: October 2009
Location: Eindhoven, The Netherland...

Junior Member

Maybe you're right about that. I get the error in .chk files (which are indeed OCL) and in extension files for Xpand (which is I guess also (a form of) OCL).

But then again, it is a problem that occurs in different parts of the Framework, that's why I figured I'd post it in the general EMF forum.

Furthermore, the problem (I think) is caused by the fact that I can't link the XString datatype correctly to the original Java String datatype, which is an Ecore related question.

But if you feel that this question is in the wrong section, by all means, move it to a correct one. I'm just hoping to get an answer to my question.

[Updated on: Mon, 08 February 2010 14:46]

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Re: Defining 'equals'-operation on custom datatype [message #513013 is a reply to message #513002]

Mon, 08 February 2010 10:24

Ed Merks

Messages: 33140
Registered: July 2009

Senior Member

RJ,

I'm really not sure what the correct place is. If it's about OCL, then
yes, ask on the OCL newsgroup/forum. If it's about Xpand, ask there.
There's nothing in Ecore itself to help or hinder this.

RJ wrote:
> Maybe you're right about that. I get the error in .chk files (which
> are indeed OCL) and in extension files for Xpand (which is I guess
> also (a form of) OCL).
>
> But then again, it is a problem that occurs in different parts of the
> Framework, that's why I figured I'd post it in the general EMF forum.
>
> Furthermore, the problem (I thinks) is caused by the fact that I can't
> link the XString datatype correctly to the original Java String
> datatype, which is an Ecore related question.
>
> But if you feel that this question is in the wrong section, by all
> means, move it to a correct one. I'm just hoping to get an answer to
> my question.

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

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Re: Defining 'equals'-operation on custom datatype [message #513043 is a reply to message #513002]

Mon, 08 February 2010 16:12

Christian Damus

Messages: 1270
Registered: July 2009
Location: Canada

Senior Member

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Hi, RJ,

The Check language is not OCL, though its syntax borrows heavily from
OCL. It is maintained in the M2T XPand project, so you should ask about
how to define the == operation for datatypes in Xpand in the
modeling.m2t newsgroup.

Cheers,

Christian

On Mon, 2010-02-08 at 15:46 +0100, RJ wrote:

> Maybe you're right about that. I get the error in .chk files (which are indeed OCL) and in extension files for Xpand (which is I guess also (a form of) OCL).
>
> But then again, it is a problem that occurs in different parts of the Framework, that's why I figured I'd post it in the general EMF forum.
>
> Furthermore, the problem (I thinks) is caused by the fact that I can't link the XString datatype correctly to the original Java String datatype, which is an Ecore related question.
>
> But if you feel that this question is in the wrong section, by all means, move it to a correct one. I'm just hoping to get an answer to my question.

--=-Epyf9Ju6eJ5SldiGXhXN
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<HTML>
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8">
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Hi, RJ, 
 
The Check language is not OCL, though its syntax borrows heavily from OCL.  It is maintained in the M2T XPand project, so you should ask about how to define the == operation for datatypes in Xpand in the modeling.m2t newsgroup. 
 
Cheers, 
 
Christian 
 
 
On Mon, 2010-02-08 at 15:46 +0100, RJ wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
Maybe you're right about that. I get the error in .chk files (which are indeed OCL) and in extension files for Xpand (which is I guess also (a form of) OCL).

But then again, it is a problem that occurs in different parts of the Framework, that's why I figured I'd post it in the general EMF forum.

Furthermore, the problem (I thinks) is caused by the fact that I can't link the XString datatype correctly to the original Java String datatype, which is an Ecore related question.

But if you feel that this question is in the wrong section, by all means, move it to a correct one. I'm just hoping to get an answer to my question.
</PRE>
</BLOCKQUOTE>
</BODY>
</HTML>

--=-Epyf9Ju6eJ5SldiGXhXN--

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