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I have a class. How do I get it's structural features? [message #495088]

Tue, 03 November 2009 17:51

Tamar Cohen

Messages: 103
Registered: July 2009

Senior Member

Hello --

I'm using reflection to do all sorts of cool automated things which I am HOPING I can contribute back to the open source world. However, I have one bit of ugliness:

I have a class. Not an EClass, just a plain class. I need to get its EStructuralFeatures. How do I do that? How can I look up a factory if I just have a class? Is there a way for me to get an EClass from a class? Mind you, I don't have an instance of the class, I just have the class itself.

thanks much

Tamar

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Re: I have a class. How do I get it's structural features? [message #495095 is a reply to message #495088]

Tue, 03 November 2009 18:12

Eike Stepper

Messages: 6680
Registered: July 2009

Senior Member

Hi Tamar,

Comments below...

Tamar Cohen schrieb:
> Hello --
>
> I'm using reflection to do all sorts of cool automated things which I
> am HOPING I can contribute back to the open source world.
I'm curious, what are you doing?

> However, I have one bit of ugliness:
> I have a class. Not an EClass, just a plain class.
Why don't you use EMF reflection?

> I need to get its EStructuralFeatures. How do I do that? How can I
> look up a factory if I just have a class?
What factory do you mean?

> Is there a way for me to get an EClass from a class? Mind you, I
> don't have an instance of the class, I just have the class itself.
I assume that you could determine the EClass of a java.lang.Class if you
have the GenModel of that EClass at hand. You'd have to traverse all
GenModels.

Cheers
/Eike

----
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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Re: I have a class. How do I get it's structural features? [message #495100 is a reply to message #495095]

Tue, 03 November 2009 18:29

Tamar Cohen

Messages: 103
Registered: July 2009

Senior Member

Hi Eike -- thanks for answering --
this is what I'm doing: Since 3.6 is not out and I couldn't get Tom's UFacekit to work I've made a simple widget generation framework. It uses introspection to generate widgets either for generic Java classes or for EMF EObjects, and you can customize the layout via Java Annotations or with code / extension points (customization includes validation and conversion and grouping and layout and read/only and and and)...

So my particular EObject instances have public constructors and it all works simply. I know that this is not always how the EMF code is generated, however, and I want to support the case where I have to look up EStructuralFeatures.

As some of these widgets will be created from classes that the developer did not write, I cannot rely on having the genmodel. How might I use EMF reflection? How can I get an EClass from a class? right now the class just implements EObject.

hopefully I will be permitted to publish my work, it's really nice for the low hanging fruit / simple UI generation.

Tamar

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Re: I have a class. How do I get it's structural features? [message #495116 is a reply to message #495100]

Tue, 03 November 2009 20:05

Ed Merks

Messages: 32937
Registered: July 2009

Senior Member

Tamar,

You generally can't get an EClass given only a java.lang.Class. If you
assume there a public constructors---EMF has an option for generating
that--then you might create an instance, cast it to EObject, and ask for
the eClass(). Alternatively, if you know the collection of possible
packages that might define the corresponding EClass, you might walk all
those package's classifiers and check if the getInstanceClass() matches.

Tamar Cohen wrote:
> Hi Eike -- thanks for answering -- this is what I'm doing: Since 3.6
> is not out and I couldn't get Tom's UFacekit to work I've made a
> simple widget generation framework. It uses introspection to generate
> widgets either for generic Java classes or for EMF EObjects, and you
> can customize the layout via Java Annotations or with code / extension
> points (customization includes validation and conversion and grouping
> and layout and read/only and and and)...
>
> So my particular EObject instances have public constructors and it all
> works simply. I know that this is not always how the EMF code is
> generated, however, and I want to support the case where I have to
> look up EStructuralFeatures.
>
> As some of these widgets will be created from classes that the
> developer did not write, I cannot rely on having the genmodel. How
> might I use EMF reflection? How can I get an EClass from a class?
> right now the class just implements EObject.
>
> hopefully I will be permitted to publish my work, it's really nice for
> the low hanging fruit / simple UI generation.
>
> Tamar

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

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Re: I have a class. How do I get it's structural features? [message #495120 is a reply to message #495116]

Tue, 03 November 2009 20:14

Tamar Cohen

Messages: 103
Registered: July 2009

Senior Member

Hi Ed --

yes, thanks, that's exactly what I was doing (instantiating a temporary EObject and looking up what I want from that), and what I want to handle is the case where there is no public constructor. Hmm, looks like I may have to add support for looking up by EClass.

thank you!

Tamar

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Re: I have a class. How do I get it's structural features? [message #495512 is a reply to message #495100]

Thu, 05 November 2009 07:48

Eike Stepper

Messages: 6680
Registered: July 2009

Senior Member

Hi Tamar,

I would not invest into own frameworks just because an upcoming
technology at Eclipse (or elsewhere) is not yet GA. Better collaborate
with the providing team to ensure that it goes into a direction that
suits your need and help stabilizing.

Cheers
/Eike

----
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Tamar Cohen schrieb:
> Hi Eike -- thanks for answering -- this is what I'm doing: Since 3.6
> is not out and I couldn't get Tom's UFacekit to work I've made a
> simple widget generation framework. It uses introspection to generate
> widgets either for generic Java classes or for EMF EObjects, and you
> can customize the layout via Java Annotations or with code / extension
> points (customization includes validation and conversion and grouping
> and layout and read/only and and and)...
>
> So my particular EObject instances have public constructors and it all
> works simply. I know that this is not always how the EMF code is
> generated, however, and I want to support the case where I have to
> look up EStructuralFeatures.
>
> As some of these widgets will be created from classes that the
> developer did not write, I cannot rely on having the genmodel. How
> might I use EMF reflection? How can I get an EClass from a class?
> right now the class just implements EObject.
>
> hopefully I will be permitted to publish my work, it's really nice for
> the low hanging fruit / simple UI generation.
>
> Tamar

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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