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Xtext2: Java Beans is standard - but only .ecore generated? [message #754450]

Wed, 02 November 2011 15:07

Johnnyboy

Messages: 39
Registered: September 2011

Member

Hello everyone,

A little question: It was said to me that Java Beans is the standard format for metamodels. I am wondering why Xtext2 than generates the .ecore/.xmi and the genmodel file - but no Java Beans? Or do the generated interfaces and Impl classes are the Java Beans presentation (just wondering - I thought JBeans have to be serializable but I did not found the key word serializable).
And as second question - how can I say that I want to generate JBeans?

Thanks in advance for any answer
Jonnyboy

[Updated on: Wed, 02 November 2011 15:35]

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Re: Xtext2: Java Beans = standard but only .ecore generated? [message #754470 is a reply to message #754450]

Wed, 02 November 2011 16:01

Ed Merks

Messages: 33216
Registered: July 2009

Senior Member

Comments below.

On 02/11/2011 4:07 PM, Johnnyboy wrote:
> Hello everyone,
>
> A little question: It was said to me that Java Beans is the standard
> format for metamodels.
Who said that? Beans on their own don't specify sufficient interesting
metadata. I.e., there's no notion of containment nor of bidirectional
references.
> I am wondering why Xtext2 than generates the .ecore/.xmi and the
> genmodel file - but no Java Beans?
Because EMF models are far more powerful than plain old Java Beans.
> Or do the generated interfaces and Impl classes are the Java Beans
> presentation
In a sense, yes.
> (just wondering - I thought JBeans have to be serializable but I did
> not found the key word serializable).
No, EMF models aren't generally java.io.Serializeable. But then can be
serialized as XMI/XML, binary, or of course in any arbitrary textual way
by defining an Xtext grammar.
>
> Thanks in advance for any answer
> Jonnyboy

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

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Re: Xtext2: Java Beans = standard but only .ecore generated? [message #754935 is a reply to message #754470]

Sat, 05 November 2011 12:59

Johnnyboy

Messages: 39
Registered: September 2011

Member

Hello,

Thank you for the answer.

An active member of this forum told me that. But "there's no notion of containment nor of bidirectional references" is truely a know out criteria. That is why I will decide to use ecore instead and the thread can be closed.

Thanks again
Jonnyboy

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Re: Xtext2: Java Beans = standard but only .ecore generated? [message #754936 is a reply to message #754935]

Sat, 05 November 2011 13:03

Christian Dietrich

Messages: 14716
Registered: July 2009

Senior Member

Hi,

you are mixing Xtext and the good old Xtend(1)/Xpand. Xpand supports different kinds of metamodels. E.g. the EMFMetamodel (which uses EMF reflective) or the "JavaBeans Metamodel" which uses Java Classes (aka Java Beans). => For Ecore Based Stuff the Java Interfaces.
Xpands Generator Component uses the "JavaBeans Metamodel" as default.

~Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

[Updated on: Sat, 05 November 2011 13:12]

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Re: Xtext2: Java Beans = standard but only .ecore generated? [message #755093 is a reply to message #754936]

Mon, 07 November 2011 11:14

Johnnyboy

Messages: 39
Registered: September 2011

Member

Hello Christian
Thanks for your answer. I asked that because I wanted to use the EMFMetamodel (.ecore) but after you said to me that JavaBeans would be the standard It was told me to get to know more about this.

Ok, XPand use Java Beans as default. But what is with the disadvantage "there's no notion of containment nor of bidirectional references"?

Thanks again for any answer
Jonnyboy

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Re: Xtext2: Java Beans = standard but only .ecore generated? [message #755097 is a reply to message #755093]

Mon, 07 November 2011 11:20

Christian Dietrich

Messages: 14716
Registered: July 2009

Senior Member

I still do not understand what your problem is.
Noone is forced to use JavaBeans Metamodel in Xpand. If you have just JavaClasses and no ecore you have to use it Wink

or built your own Metamodel Contributor for Xpand. If you have ecore it is no problemto use JavaBeans since the ecore java classes have Conainer/Contents relations explicitely.

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Xtext2: Java Beans = standard but only .ecore generated? [message #755108 is a reply to message #755097]

Mon, 07 November 2011 12:27

Johnnyboy

Messages: 39
Registered: September 2011

Member

THX again for your answer Smile

My last problem was that "there's no notion of containment nor of bidirectional
references" for JavaBeans" (which was said above).
If you say that this is no problem because "JavaBeans since the ecore java classes have Conainer/Contents relations explicitely" than that should be ok. My team leader says that we should use the standard if there is no problem. With model annotaion and type/containment attributes you can specify the containment relationship I think.

Ok, that should be it for now and thanks again
Jonnyboy

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