Skip to main content


Eclipse Community Forums
Forum Search:

Search      Help    Register    Login    Home
Home » Modeling » EMF » [Xcore] What is the advantage of "derived feature" from "operation"
[Xcore] What is the advantage of "derived feature" from "operation" [message #1433879] Mon, 29 September 2014 11:10 Go to next message
Ravi Nallappan is currently offline Ravi NallappanFriend
Messages: 8
Registered: September 2014
Junior Member
Hi,

I like the fact I now able to specify behaviour in more natural way using Xcore on top of ecore. i.e less hacking on generated codes.

Questions based on eclipse wiki , how does this "derived String lastName get {...}" different from say defining an operation - "op String getLastName {..}", initially I was under impression that this works as lazy initialization - but from generated code, it does not have the actual attribute lastName, the calculation is done everytime lastName feature is called.

Additionally, "derived String lastName set {..}" how does this works? how do we access the set parameters?

Thank You.
Re: [Xcore] What is the advantage of "derived feature" from "operation&am [message #1434002 is a reply to message #1433879] Mon, 29 September 2014 14:30 Go to previous messageGo to next message
Ed Merks is currently offline Ed MerksFriend
Messages: 30351
Registered: July 2009
Senior Member
Ravi,

Comments below.

On 29/09/2014 2:49 PM, Ravi Nallappan wrote:
> Hi,
>
> I like the fact I now able to specify behaviour in more natural way
> using Xcore on top of ecore. i.e less hacking on generated codes.
>
> Questions based on
> https://wiki.eclipse.org/Xcore#Specifying_a_Derived_Feature , how does
> this "derived String lastName get {...}" different from say defining
> an operation - "op String getLastName {..}", initially I was under
> impression that this works as lazy initialization - but from generated
> code, it does not have the actual attribute lastName, the calculation
> is done everytime lastName feature is called.
It's certainly not visibly different in the Java API, but reflectively,
it's a property, so you can see it in the properties view, for example.
>
> Additionally, "derived String lastName set {..}" how does this works?
> how do we access the set parameters?
It doesn't really work. I.e., it doesn't work at all, so while it's in
the grammar, there really no proper implementation for it. At some
point I'd like to be able to declare fields for the implementation class
(distinct from features which are reflectively visible)... But that's
not trivial and won't be done anytime soon...
>
> Thank You.
Re: [Xcore] What is the advantage of "derived feature" from "operation&am [message #1434494 is a reply to message #1434002] Tue, 30 September 2014 06:54 Go to previous message
Thomas Schindl is currently offline Thomas SchindlFriend
Messages: 6494
Registered: July 2009
Senior Member
On 29.09.14 07:30, Ed Merks wrote:
> Ravi,
>
> Comments below.
>
> On 29/09/2014 2:49 PM, Ravi Nallappan wrote:
>> Hi,
>>
>> I like the fact I now able to specify behaviour in more natural way
>> using Xcore on top of ecore. i.e less hacking on generated codes.
>>
>> Questions based on
>> https://wiki.eclipse.org/Xcore#Specifying_a_Derived_Feature , how does
>> this "derived String lastName get {...}" different from say defining
>> an operation - "op String getLastName {..}", initially I was under
>> impression that this works as lazy initialization - but from generated
>> code, it does not have the actual attribute lastName, the calculation
>> is done everytime lastName feature is called.
> It's certainly not visibly different in the Java API, but reflectively,
> it's a property, so you can see it in the properties view, for example.

a feature value is observable using Adapters which does not work for
operations.

Tom
Previous Topic:Identify unset/undefined attributes in Entities
Next Topic:[CDO] Postgres Reference List update problem
Goto Forum:
  


Current Time: Sun Aug 18 23:42:06 GMT 2019

Powered by FUDForum. Page generated in 0.01509 seconds
.:: Contact :: Home ::.

Powered by: FUDforum 3.0.2.
Copyright ©2001-2010 FUDforum Bulletin Board Software

Back to the top