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[QVTo] Adding a new element [message #653366]

Wed, 09 February 2011 14:37

Haffi

Messages: 39
Registered: November 2010

Member

Hi, I'm sorry for asking such a simple question but how do I create a new element in QVTo? I've got this code:

var newActivity : UML::ActivityNode;
newActivity.name := "someName";

But the variable is always null even though I change it's properties. I guess it's something simple I'm missing but I haven't found any examples of how this is done properly.

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Re: [QVTo] Adding a new element [message #653375 is a reply to message #653366]

Wed, 09 February 2011 15:08

Dennis Hendriks

Messages: 74
Registered: January 2010
Location: The Netherlands

Member

Hi Haffi,

I assume this is some sort of local variable. You have to create a new
object (instance of UML::ActivityNode). Declaring a variable of a certain
type doesn't automatically create a new instance of such a type.

You could change your code to:

var newActivity : UML::ActivityNode;
newActivity := object UML:ActivityNode {
name := "someName";
}

Best regards,
Dennis

Haffi wrote:
> Hi, I'm sorry for asking such a simple question but how do I create a
> new element in QVTo? I've got this code:
>
> var newActivity : UML::ActivityNode;
> newActivity.name := "someName";
>
> But the variable is always null even though I change it's properties. I
> guess it's something simple I'm missing but I haven't found any examples
> of how this is done properly.

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Re: [QVTo] Adding a new element [message #653651 is a reply to message #653375]

Thu, 10 February 2011 14:36

Haffi

Messages: 39
Registered: November 2010

Member

Hi, thank you for your detailed answer. I got a new problem though, an error message says: "Can't instantiate abstract type 'uml::ActivityNode'" Do you have any idea what's going on?

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Re: [QVTo] Adding a new element [message #653782 is a reply to message #653651]

Fri, 11 February 2011 07:10

Dennis Hendriks

Messages: 74
Registered: January 2010
Location: The Netherlands

Member

If a class is abstract, you cannot create an instance of it. That is kind
of the whole point of having an abstract class. You have to create an
instance of one of its derived classes. This is all standard object
oriented programming, and it is exactly the way that any object oriented
programming language works, like Java, C#, etc.

Dennis

Haffi wrote:
> Hi, thank you for your detailed answer. I got a new problem though, an
> error message says: "Can't instantiate abstract type
> 'uml::ActivityNode'" Do you have any idea what's going on?

Report message to a moderator