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Home » Modeling » EMF » Getting started with EMF
Getting started with EMF [message #420520] Tue, 01 July 2008 22:00 Go to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Hi,

I am starting a java project, I am willing to use EMF in order to design
a persistent support for my application data. I am not sure that I've
fully understood what can do and what cannot do EMF, that's why i'd like
to ask you a sequence of newbie questions regarding both features and
the way to use them.

First of all, am I right using EMF in order to :
- Modeling my objects data and relationship in an UML way
- Support persistence first in a simple way using XMI then later
Hibernate (or any fitting solution)
- Generate my data layer source code in an MDA way

Is it a good idea to use EMF out of a pure eclipse context ? It is say
that is possible to use it in a standalone context, there is maybe a
more convenient way to use it through a framework maybe ?
My genmodel removes edit and editor classes since that's really eclipse
related features, am I right ?

I am planning to store large amount of data. I fear that the standard
XMI serialization may lead to long loading/saving times ? Is EMF
accessing lazily to stored object ? Is Hibernate (or any database driven
solution) better for large amount of data ?

Should I limit the use of EMF for my pure-data layer or is it
recommended to generalize the usage to the whole project ?

I also miss newcomer friendly blogs or tutorials out of the eclipse
documentation. Beside of this newsgroup, where should I search for
proper coding/usage standards or examples for EMF ?

How will EMF react if I try to load serialized data from a previous
model with a newly generated source code ? Both with minor updates (new
properties) to major changes (new object relationship, interfaces,
removed objets...) What is the standard way to work in order to support
data model upgrade ?

I'd like to generate my data objects from xml configuration using
factory patterns. I'd also like to update existing object from new
configuration features from one public code release to another. Should I
extend the emf package factory class content or define factory/updater
object outside of emf ?

Is anyone knows if the Maven team is going to support (up to date)
eclipse jars (emf mainly) rather than forcing me to use the
(undocumented) emf repository ?

I guess that's enough for my first post. I don't expect complete
explanations for all of this but general indications for me to getting
started with that beautiful tool.

Thanks in advance for your help !

Guillaume
Re: Getting started with EMF [message #420521 is a reply to message #420520] Tue, 01 July 2008 22:03 Go to previous messageGo to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Furthermore, I may need some good literacy. Is there any must-have
reference book around the casual EMF usage ?

Guillaume

Guillaume Boddaert a écrit :
> Hi,
>
> I am starting a java project, I am willing to use EMF in order to design
> a persistent support for my application data. I am not sure that I've
> fully understood what can do and what cannot do EMF, that's why i'd like
> to ask you a sequence of newbie questions regarding both features and
> the way to use them.
>
> First of all, am I right using EMF in order to :
> - Modeling my objects data and relationship in an UML way
> - Support persistence first in a simple way using XMI then later
> Hibernate (or any fitting solution)
> - Generate my data layer source code in an MDA way
>
> Is it a good idea to use EMF out of a pure eclipse context ? It is say
> that is possible to use it in a standalone context, there is maybe a
> more convenient way to use it through a framework maybe ?
> My genmodel removes edit and editor classes since that's really eclipse
> related features, am I right ?
>
> I am planning to store large amount of data. I fear that the standard
> XMI serialization may lead to long loading/saving times ? Is EMF
> accessing lazily to stored object ? Is Hibernate (or any database driven
> solution) better for large amount of data ?
>
> Should I limit the use of EMF for my pure-data layer or is it
> recommended to generalize the usage to the whole project ?
>
> I also miss newcomer friendly blogs or tutorials out of the eclipse
> documentation. Beside of this newsgroup, where should I search for
> proper coding/usage standards or examples for EMF ?
>
> How will EMF react if I try to load serialized data from a previous
> model with a newly generated source code ? Both with minor updates (new
> properties) to major changes (new object relationship, interfaces,
> removed objets...) What is the standard way to work in order to support
> data model upgrade ?
>
> I'd like to generate my data objects from xml configuration using
> factory patterns. I'd also like to update existing object from new
> configuration features from one public code release to another. Should I
> extend the emf package factory class content or define factory/updater
> object outside of emf ?
>
> Is anyone knows if the Maven team is going to support (up to date)
> eclipse jars (emf mainly) rather than forcing me to use the
> (undocumented) emf repository ?
>
> I guess that's enough for my first post. I don't expect complete
> explanations for all of this but general indications for me to getting
> started with that beautiful tool.
>
> Thanks in advance for your help !
>
> Guillaume
Re: Getting started with EMF [message #420524 is a reply to message #420521] Tue, 01 July 2008 23:35 Go to previous messageGo to next message
Will Horn is currently offline Will HornFriend
Messages: 265
Registered: July 2009
Senior Member
I think this book will be helpful (when it finally is released)
http://www.amazon.com/EMF-Eclipse-Modeling-Framework-2nd/dp/ 0321331885/ref=pd_bbs_1?ie=UTF8&s=books&qid=12149551 15&sr=8-1

In the meantime there is an older version that is still more or less applicable. Also, my friend
has a Safari subscription and was able to view a pre-release online version.

Have you been to http://www.eclipse.org/modeling/emf/docs/? That's where I started.

I would at least start with using EMF in Eclipse, but I know it can be used standalone.

Hopefully someone else with more experience/knowledge will respond to your other questions :)

Guillaume Boddaert wrote:
> Furthermore, I may need some good literacy. Is there any must-have
> reference book around the casual EMF usage ?
>
> Guillaume
>
> Guillaume Boddaert a écrit :
>> Hi,
>>
>> I am starting a java project, I am willing to use EMF in order to design
>> a persistent support for my application data. I am not sure that I've
>> fully understood what can do and what cannot do EMF, that's why i'd like
>> to ask you a sequence of newbie questions regarding both features and
>> the way to use them.
>>
>> First of all, am I right using EMF in order to :
>> - Modeling my objects data and relationship in an UML way
>> - Support persistence first in a simple way using XMI then later
>> Hibernate (or any fitting solution)
>> - Generate my data layer source code in an MDA way
>>
>> Is it a good idea to use EMF out of a pure eclipse context ? It is say
>> that is possible to use it in a standalone context, there is maybe a
>> more convenient way to use it through a framework maybe ?
>> My genmodel removes edit and editor classes since that's really eclipse
>> related features, am I right ?
>>
>> I am planning to store large amount of data. I fear that the standard
>> XMI serialization may lead to long loading/saving times ? Is EMF
>> accessing lazily to stored object ? Is Hibernate (or any database driven
>> solution) better for large amount of data ?
>>
>> Should I limit the use of EMF for my pure-data layer or is it
>> recommended to generalize the usage to the whole project ?
>>
>> I also miss newcomer friendly blogs or tutorials out of the eclipse
>> documentation. Beside of this newsgroup, where should I search for
>> proper coding/usage standards or examples for EMF ?
>>
>> How will EMF react if I try to load serialized data from a previous
>> model with a newly generated source code ? Both with minor updates (new
>> properties) to major changes (new object relationship, interfaces,
>> removed objets...) What is the standard way to work in order to support
>> data model upgrade ?
>>
>> I'd like to generate my data objects from xml configuration using
>> factory patterns. I'd also like to update existing object from new
>> configuration features from one public code release to another. Should I
>> extend the emf package factory class content or define factory/updater
>> object outside of emf ?
>>
>> Is anyone knows if the Maven team is going to support (up to date)
>> eclipse jars (emf mainly) rather than forcing me to use the
>> (undocumented) emf repository ?
>>
>> I guess that's enough for my first post. I don't expect complete
>> explanations for all of this but general indications for me to getting
>> started with that beautiful tool.
>>
>> Thanks in advance for your help !
>>
>> Guillaume
Re: Getting started with EMF [message #420531 is a reply to message #420521] Wed, 02 July 2008 07:38 Go to previous messageGo to next message
Martin Taal is currently offline Martin TaalFriend
Messages: 5468
Registered: July 2009
Senior Member
Hi Guillaume,
I can only react on part of your post. For EMF and Hibernate you can use the EMF Teneo component.
This component supports automatic mapping of your model to a relational store (using hibernate) and
supports EMF-Hibernate at runtime.

A few reasons for using a relational store compared to xmi/xml is when you have larger datasets
which need to be available centrally. Also when you require relational-like querying functionality
then it can make sense to use a rdb/hibernate: paging, joining, grouping/aggregation etc. and
ofcourse if you require other rdb functionality such as acid behavior.

If you work with distributed clients then it can make sense to look at the EMF CDO project also.
Eike can say more about this.

You can use EMF standalone (outside of Eclipse), the minimal setup requires 3 of the EMF jar files.

Regarding loading large datasets, EMF has a strong proxy concept which makes it possible to work
with large datasets in xml/xmi also. But there are others here who can tell you much more about this.

gr. Martin

Guillaume Boddaert wrote:
> Furthermore, I may need some good literacy. Is there any must-have
> reference book around the casual EMF usage ?
>
> Guillaume
>
> Guillaume Boddaert a écrit :
>> Hi,
>>
>> I am starting a java project, I am willing to use EMF in order to design
>> a persistent support for my application data. I am not sure that I've
>> fully understood what can do and what cannot do EMF, that's why i'd like
>> to ask you a sequence of newbie questions regarding both features and
>> the way to use them.
>>
>> First of all, am I right using EMF in order to :
>> - Modeling my objects data and relationship in an UML way
>> - Support persistence first in a simple way using XMI then later
>> Hibernate (or any fitting solution)
>> - Generate my data layer source code in an MDA way
>>
>> Is it a good idea to use EMF out of a pure eclipse context ? It is say
>> that is possible to use it in a standalone context, there is maybe a
>> more convenient way to use it through a framework maybe ?
>> My genmodel removes edit and editor classes since that's really eclipse
>> related features, am I right ?
>>
>> I am planning to store large amount of data. I fear that the standard
>> XMI serialization may lead to long loading/saving times ? Is EMF
>> accessing lazily to stored object ? Is Hibernate (or any database driven
>> solution) better for large amount of data ?
>>
>> Should I limit the use of EMF for my pure-data layer or is it
>> recommended to generalize the usage to the whole project ?
>>
>> I also miss newcomer friendly blogs or tutorials out of the eclipse
>> documentation. Beside of this newsgroup, where should I search for
>> proper coding/usage standards or examples for EMF ?
>>
>> How will EMF react if I try to load serialized data from a previous
>> model with a newly generated source code ? Both with minor updates (new
>> properties) to major changes (new object relationship, interfaces,
>> removed objets...) What is the standard way to work in order to support
>> data model upgrade ?
>>
>> I'd like to generate my data objects from xml configuration using
>> factory patterns. I'd also like to update existing object from new
>> configuration features from one public code release to another. Should I
>> extend the emf package factory class content or define factory/updater
>> object outside of emf ?
>>
>> Is anyone knows if the Maven team is going to support (up to date)
>> eclipse jars (emf mainly) rather than forcing me to use the
>> (undocumented) emf repository ?
>>
>> I guess that's enough for my first post. I don't expect complete
>> explanations for all of this but general indications for me to getting
>> started with that beautiful tool.
>>
>> Thanks in advance for your help !
>>
>> Guillaume


--

With Regards, Martin Taal

Springsite/Elver.org
Office: Hardwareweg 4, 3821 BV Amersfoort
Postal: Nassaulaan 7, 3941 EC Doorn
The Netherlands
Cell: +31 (0)6 288 48 943
Tel: +31 (0)84 420 2397
Fax: +31 (0)84 225 9307
Mail: mtaal@springsite.com - mtaal@elver.org
Web: www.springsite.com - www.elver.org
Re: Getting started with EMF [message #420533 is a reply to message #420521] Wed, 02 July 2008 07:49 Go to previous messageGo to next message
Eike Stepper is currently offline Eike StepperFriend
Messages: 6682
Registered: July 2009
Senior Member
Hi Guillaume,

CDO aims to be a complete model repository solution and an extensible
framework for distributed, shared, transaction and persistent models.
It covers the whole stack from the client (possibly) over the network
down to a central model repository with exchangeable back-end support.
Hibernate and Martin's Teneo for automatic mapping is also supported on
the server side.

Please have a look at the wiki http://wiki.eclipse.org/CDO and check out
my EclipseCon presentation:
http://www.eclipsecon.org/2008/index.php?page=sub/&id=58

Of course you're also welcome to ask more detailed questions here ;-)

Cheers
/Eike



Guillaume Boddaert schrieb:
> Furthermore, I may need some good literacy. Is there any must-have
> reference book around the casual EMF usage ?
>
> Guillaume
>
> Guillaume Boddaert a écrit :
>
>> Hi,
>>
>> I am starting a java project, I am willing to use EMF in order to design
>> a persistent support for my application data. I am not sure that I've
>> fully understood what can do and what cannot do EMF, that's why i'd like
>> to ask you a sequence of newbie questions regarding both features and
>> the way to use them.
>>
>> First of all, am I right using EMF in order to :
>> - Modeling my objects data and relationship in an UML way
>> - Support persistence first in a simple way using XMI then later
>> Hibernate (or any fitting solution)
>> - Generate my data layer source code in an MDA way
>>
>> Is it a good idea to use EMF out of a pure eclipse context ? It is say
>> that is possible to use it in a standalone context, there is maybe a
>> more convenient way to use it through a framework maybe ?
>> My genmodel removes edit and editor classes since that's really eclipse
>> related features, am I right ?
>>
>> I am planning to store large amount of data. I fear that the standard
>> XMI serialization may lead to long loading/saving times ? Is EMF
>> accessing lazily to stored object ? Is Hibernate (or any database driven
>> solution) better for large amount of data ?
>>
>> Should I limit the use of EMF for my pure-data layer or is it
>> recommended to generalize the usage to the whole project ?
>>
>> I also miss newcomer friendly blogs or tutorials out of the eclipse
>> documentation. Beside of this newsgroup, where should I search for
>> proper coding/usage standards or examples for EMF ?
>>
>> How will EMF react if I try to load serialized data from a previous
>> model with a newly generated source code ? Both with minor updates (new
>> properties) to major changes (new object relationship, interfaces,
>> removed objets...) What is the standard way to work in order to support
>> data model upgrade ?
>>
>> I'd like to generate my data objects from xml configuration using
>> factory patterns. I'd also like to update existing object from new
>> configuration features from one public code release to another. Should I
>> extend the emf package factory class content or define factory/updater
>> object outside of emf ?
>>
>> Is anyone knows if the Maven team is going to support (up to date)
>> eclipse jars (emf mainly) rather than forcing me to use the
>> (undocumented) emf repository ?
>>
>> I guess that's enough for my first post. I don't expect complete
>> explanations for all of this but general indications for me to getting
>> started with that beautiful tool.
>>
>> Thanks in advance for your help !
>>
>> Guillaume
>>


Re: Getting started with EMF [message #420535 is a reply to message #420531] Wed, 02 July 2008 09:24 Go to previous messageGo to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Thanks for your answer.

I have my reply : EMF support Hibernate backend through Teneo component
(I also read things about Elver). But as i don't wan't to open too many
doors at once, i'll keep on using XMI in a first time. I'll migrate
toward other store engine later. As EMF support proxy concept, i am
quite confident for a first run with XMI only.

I already deployed the 3 emf core jars to my project, it seems to run
correctly.

I'll also answer concerning CDO here (thanks Eike for your answer). This
is a really great framework but I don't think we'll need this for our
projet. Although we are serving data to clients, we are not wishing
people to access the whole dataset but personnal subsets. We choiced to
send XML dataset through webservices.

I am now aware about XMI performance and alternate store engines
availibility. I'll wait for others answers concerning my others
questions and come back with more accurate topics (that's hard to get
back to the good old newsgroup after thoses bulletin-boards. :) )

Thanks people !

Martin Taal a écrit :
> Hi Guillaume,
> I can only react on part of your post. For EMF and Hibernate you can use
> the EMF Teneo component. This component supports automatic mapping of
> your model to a relational store (using hibernate) and supports
> EMF-Hibernate at runtime.
>
> A few reasons for using a relational store compared to xmi/xml is when
> you have larger datasets which need to be available centrally. Also when
> you require relational-like querying functionality then it can make
> sense to use a rdb/hibernate: paging, joining, grouping/aggregation etc.
> and ofcourse if you require other rdb functionality such as acid behavior.
>
> If you work with distributed clients then it can make sense to look at
> the EMF CDO project also. Eike can say more about this.
>
> You can use EMF standalone (outside of Eclipse), the minimal setup
> requires 3 of the EMF jar files.
>
> Regarding loading large datasets, EMF has a strong proxy concept which
> makes it possible to work with large datasets in xml/xmi also. But there
> are others here who can tell you much more about this.
>
> gr. Martin
>
> Guillaume Boddaert wrote:
Re: Getting started with EMF [message #420536 is a reply to message #420524] Wed, 02 July 2008 09:31 Go to previous messageGo to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Ok, i'll try to keep an eye on this book. I don't want to buy an sightly
outdated one.

Yes I already overviewed the documentation project for EMF. That's a lot
of information for sure, but I may need a more friendly book. As the
book release date is not known and that I want to progress I'll be
forced to read the whole thing. That's a lot to learn with a steep
learning curve. :)

I'll managed to make my way through it.

Thanks for your answer Will.

Guillaume

Will Horn a écrit :
> I think this book will be helpful (when it finally is released)
> http://www.amazon.com/EMF-Eclipse-Modeling-Framework-2nd/dp/ 0321331885/ref=pd_bbs_1?ie=UTF8&s=books&qid=12149551 15&sr=8-1
>
>
> In the meantime there is an older version that is still more or less
> applicable. Also, my friend has a Safari subscription and was able to
> view a pre-release online version.
>
> Have you been to http://www.eclipse.org/modeling/emf/docs/? That's where
> I started.
>
> I would at least start with using EMF in Eclipse, but I know it can be
> used standalone.
>
> Hopefully someone else with more experience/knowledge will respond to
> your other questions :)
Re: Getting started with EMF [message #420538 is a reply to message #420535] Wed, 02 July 2008 09:57 Go to previous messageGo to next message
Eike Stepper is currently offline Eike StepperFriend
Messages: 6682
Registered: July 2009
Senior Member
Hi Guillaume,

Comments below...


Guillaume Boddaert schrieb:
> Thanks for your answer.
>
> I have my reply : EMF support Hibernate backend through Teneo
> component (I also read things about Elver). But as i don't wan't to
> open too many doors at once, i'll keep on using XMI in a first time.
> I'll migrate toward other store engine later. As EMF support proxy
> concept, i am quite confident for a first run with XMI only.
>
> I already deployed the 3 emf core jars to my project, it seems to run
> correctly.
>
> I'll also answer concerning CDO here (thanks Eike for your answer).
> This is a really great framework but I don't think we'll need this for
> our projet. Although we are serving data to clients, we are not
> wishing people to access the whole dataset but personnal subsets. We
> choiced to send XML dataset through webservices.
Of course I respect any choice you meet but, just for my understanding,
why do you think that CDO is restricted to providing access to whole
data sets?
You may have other criteria to decide against CDO. Again, no problem.
But the reason you give here seems to mis-judge CDO ;-)

Cheers
/Eike

>
> I am now aware about XMI performance and alternate store engines
> availibility. I'll wait for others answers concerning my others
> questions and come back with more accurate topics (that's hard to get
> back to the good old newsgroup after thoses bulletin-boards. :) )
>
> Thanks people !
>
> Martin Taal a écrit :
>> Hi Guillaume,
>> I can only react on part of your post. For EMF and Hibernate you can
>> use the EMF Teneo component. This component supports automatic
>> mapping of your model to a relational store (using hibernate) and
>> supports EMF-Hibernate at runtime.
>>
>> A few reasons for using a relational store compared to xmi/xml is
>> when you have larger datasets which need to be available centrally.
>> Also when you require relational-like querying functionality then it
>> can make sense to use a rdb/hibernate: paging, joining,
>> grouping/aggregation etc. and ofcourse if you require other rdb
>> functionality such as acid behavior.
>>
>> If you work with distributed clients then it can make sense to look
>> at the EMF CDO project also. Eike can say more about this.
>>
>> You can use EMF standalone (outside of Eclipse), the minimal setup
>> requires 3 of the EMF jar files.
>>
>> Regarding loading large datasets, EMF has a strong proxy concept
>> which makes it possible to work with large datasets in xml/xmi also.
>> But there are others here who can tell you much more about this.
>>
>> gr. Martin
>>
>> Guillaume Boddaert wrote:


Re: Getting started with EMF [message #420543 is a reply to message #420538] Wed, 02 July 2008 10:27 Go to previous messageGo to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Eike Stepper a écrit :
> Hi Guillaume,
>
> Of course I respect any choice you meet but, just for my understanding,
> why do you think that CDO is restricted to providing access to whole
> data sets?
> You may have other criteria to decide against CDO. Again, no problem.
> But the reason you give here seems to mis-judge CDO ;-)
>
> Cheers
> /Eike

Thanks for this correction. Indeed I didn't verified this precisely.
This is indeed a great feature, I understand your need to correct my
misjudgment. Would be a shame to defame the project features.
Good Job, Eike.

Guillaume
Re: Getting started with EMF [message #420547 is a reply to message #420524] Wed, 02 July 2008 10:50 Go to previous messageGo to next message
gary s thompson is currently offline gary s thompsonFriend
Messages: 92
Registered: July 2009
Member
Hi

comments below

Will Horn wrote:

> I think this book will be helpful (when it finally is released)
>
http://www.amazon.com/EMF-Eclipse-Modeling-Framework-2nd/dp/ 0321331885/ref=pd_bbs_1?ie=UTF8&s=books&qid=12149551 15&sr=8-1

> In the meantime there is an older version that is still more or less
applicable. Also, my friend
> has a Safari subscription and was able to view a pre-release online version.


There is also a rough cut of the book available at
http://safari.informit.com/9780321331885 this allows you to buy various
bundled versions

Online, PDF and Print Book Bundle USD $67.48
Online and PDF Access USD $34.99
Print Book Pre-Order USD $34.99

This has most of the text but many of the diagrams are missing, however,
it is still informative and more future proof than the first edition ;-)

regards
gary

> Have you been to http://www.eclipse.org/modeling/emf/docs/? That's where I
started.

> I would at least start with using EMF in Eclipse, but I know it can be used
standalone.

> Hopefully someone else with more experience/knowledge will respond to your
other questions :)

> Guillaume Boddaert wrote:
>> Furthermore, I may need some good literacy. Is there any must-have
>> reference book around the casual EMF usage ?
>>
>> Guillaume
>>
>> Guillaume Boddaert a ï¿œcrit :
>>> Hi,
>>>
>>> I am starting a java project, I am willing to use EMF in order to design
>>> a persistent support for my application data. I am not sure that I've
>>> fully understood what can do and what cannot do EMF, that's why i'd like
>>> to ask you a sequence of newbie questions regarding both features and
>>> the way to use them.
>>>
>>> First of all, am I right using EMF in order to :
>>> - Modeling my objects data and relationship in an UML way
>>> - Support persistence first in a simple way using XMI then later
>>> Hibernate (or any fitting solution)
>>> - Generate my data layer source code in an MDA way
>>>
>>> Is it a good idea to use EMF out of a pure eclipse context ? It is say
>>> that is possible to use it in a standalone context, there is maybe a
>>> more convenient way to use it through a framework maybe ?
>>> My genmodel removes edit and editor classes since that's really eclipse
>>> related features, am I right ?
>>>
>>> I am planning to store large amount of data. I fear that the standard
>>> XMI serialization may lead to long loading/saving times ? Is EMF
>>> accessing lazily to stored object ? Is Hibernate (or any database driven
>>> solution) better for large amount of data ?
>>>
>>> Should I limit the use of EMF for my pure-data layer or is it
>>> recommended to generalize the usage to the whole project ?
>>>
>>> I also miss newcomer friendly blogs or tutorials out of the eclipse
>>> documentation. Beside of this newsgroup, where should I search for
>>> proper coding/usage standards or examples for EMF ?
>>>
>>> How will EMF react if I try to load serialized data from a previous
>>> model with a newly generated source code ? Both with minor updates (new
>>> properties) to major changes (new object relationship, interfaces,
>>> removed objets...) What is the standard way to work in order to support
>>> data model upgrade ?
>>>
>>> I'd like to generate my data objects from xml configuration using
>>> factory patterns. I'd also like to update existing object from new
>>> configuration features from one public code release to another. Should I
>>> extend the emf package factory class content or define factory/updater
>>> object outside of emf ?
>>>
>>> Is anyone knows if the Maven team is going to support (up to date)
>>> eclipse jars (emf mainly) rather than forcing me to use the
>>> (undocumented) emf repository ?
>>>
>>> I guess that's enough for my first post. I don't expect complete
>>> explanations for all of this but general indications for me to getting
>>> started with that beautiful tool.
>>>
>>> Thanks in advance for your help !
>>>
>>> Guillaume
Re: Getting started with EMF [message #420577 is a reply to message #420520] Wed, 02 July 2008 16:30 Go to previous messageGo to next message
Ed Merks is currently offline Ed MerksFriend
Messages: 33113
Registered: July 2009
Senior Member
This is a multi-part message in MIME format.
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Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Guillaume,

It's gratifying to see lots of folks helped answer your questions. I
think this gives you a sense of what a great community has built up in
the modeling space at Eclipse. More comments below.

Guillaume Boddaert wrote:
> Hi,
>
> I am starting a java project, I am willing to use EMF in order to design
> a persistent support for my application data. I am not sure that I've
> fully understood what can do and what cannot do EMF, that's why i'd like
> to ask you a sequence of newbie questions regarding both features and
> the way to use them.
>
> First of all, am I right using EMF in order to :
> - Modeling my objects data and relationship in an UML way
>
I suppose so, but you could model them using XML Schema instead, though
XML Schema is deficient in a number of important ways, including the
ability to specify strongly typed non-containment references; EMF
support schema annotations to overcome these limitations.
> - Support persistence first in a simple way using XMI then later
> Hibernate (or any fitting solution)
>
Yes, persistence format is a separate issue from the design of your mmodel.
> - Generate my data layer source code in an MDA way
>
You left out the "TM" in MDA. :-P
> Is it a good idea to use EMF out of a pure eclipse context ?
Yes.
> It is say
> that is possible to use it in a standalone context, there is maybe a
> more convenient way to use it through a framework maybe ?
>
The core runtime and edit support are designed such that the plugin jars
can be used as jars on the classpath with no other Eclipse dependencies
on the classpath.
> My genmodel removes edit and editor classes since that's really eclipse
> related features, am I right ?
>
The edit stuff is independent of Eclipse and might be used to build a
swing-based application (someone is writing an article about having done
that) or it might be used in a web-based context. The editor is tied to
Eclipse; there's also an RCP flavor of it that doesn't rely on there
being a workspace.
> I am planning to store large amount of data. I fear that the standard
> XMI serialization may lead to long loading/saving times ?
Massively large files as opposed to a larger number of smaller files are
generally something to avoid. I.e., it's better to decompose your data
into reasonable size units. This is true no matter what technology you
use, i.e., even DOM will not be happy with massively large files.
> Is EMF
> accessing lazily to stored object ? Is Hibernate (or any database driven
> solution) better for large amount of data ?
>
Even purely XMI-based loading is lazy in the sense of only loading a
single resource and not loading referenced resources until you need to
access the data in them.
> Should I limit the use of EMF for my pure-data layer or is it
> recommended to generalize the usage to the whole project ?
>
I can't imagine somewhere that it would not (and I usually have a pretty
good imagination)
> I also miss newcomer friendly blogs or tutorials out of the eclipse
> documentation. Beside of this newsgroup, where should I search for
> proper coding/usage standards or examples for EMF ?
>
All things EMF are on the documentation page accessible from the
navigation bar on the home page. I love reading the blogs on the planet:
> How will EMF react if I try to load serialized data from a previous
> model with a newly generated source code ?
You mean after the model as changed? If the changes are binary
compatible, it should be fine. There even load options to support
forward compatibility, i.e., that would allow an older model to read a
newer serialization.
> Both with minor updates (new
> properties) to major changes (new object relationship, interfaces,
> removed objets...) What is the standard way to work in order to support
> data model upgrade ?
>
The additions are easy to handle so that won't be a problem. Removal is
obviously tricky, but, as I said, there is a load option to help:

/**
* This options allows you to record unknown features during
deserialization/loading.
* The default is <code>Boolean.FALSE</code> unless set to
<code>Boolean.TRUE</code> explicitly.
* The unknown features and their values can be accessed via
getEObjectToExtensionMap().
* @see #getEObjectToExtensionMap()
*/
String OPTION_RECORD_UNKNOWN_FEATURE = "RECORD_UNKNOWN_FEATURE";

The recorded information can be post processed to throw it away if
that's the desired effect.
> I'd like to generate my data objects from xml configuration using
> factory patterns. I'd also like to update existing object from new
> configuration features from one public code release to another. Should I
> extend the emf package factory class content or define factory/updater
> object outside of emf ?
>
I'm not sure what this question is driving at. EMF is a merging
generator, so when you change the model, you just regenerate and what
you need shows up.
> Is anyone knows if the Maven team is going to support (up to date)
> eclipse jars (emf mainly) rather than forcing me to use the
> (undocumented) emf repository ?
>
I believe Nick is already producing maven results for each build, but I
don't know where he's "hiding" them.

> I guess that's enough for my first post. I don't expect complete
> explanations for all of this but general indications for me to getting
> started with that beautiful tool.
>
> Thanks in advance for your help !
>
> Guillaume
>

--------------000402010105070700050903
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Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
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Guillaume,<br>
<br>
It's gratifying to see lots of folks helped answer your questions.&nbsp; I
think this gives you a sense of what a great community has built up in
the modeling space at Eclipse.&nbsp; More comments below.<br>
<br>
Guillaume Boddaert wrote:
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">Hi,

I am starting a java project, I am willing to use EMF in order to design
a persistent support for my application data. I am not sure that I've
fully understood what can do and what cannot do EMF, that's why i'd like
to ask you a sequence of newbie questions regarding both features and
the way to use them.

First of all, am I right using EMF in order to :
- Modeling my objects data and relationship in an UML way
</pre>
</blockquote>
I suppose so, but you could model them using XML Schema instead, though
XML Schema is deficient in a number of important ways, including the
ability to specify strongly typed non-containment references; EMF
support schema annotations to overcome these limitations.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap=""> - Support persistence first in a simple way using XMI then later
Hibernate (or any fitting solution)
</pre>
</blockquote>
Yes, persistence format is a separate issue from the design of your
mmodel.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap=""> - Generate my data layer source code in an MDA way
</pre>
</blockquote>
You left out the "TM" in MDA. :-P<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
Is it a good idea to use EMF out of a pure eclipse context ?</pre>
</blockquote>
Yes.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap=""> It is say
that is possible to use it in a standalone context, there is maybe a
more convenient way to use it through a framework maybe ?
</pre>
</blockquote>
The core runtime and edit support are designed such that the plugin
jars can be used as jars on the classpath with no other Eclipse
dependencies on the classpath.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">My genmodel removes edit and editor classes since that's really eclipse
related features, am I right ?
</pre>
</blockquote>
The edit stuff is independent of Eclipse and might be used to build a
swing-based application (someone is writing an article about having
done that) or it might be used in a web-based context.&nbsp; The editor is
tied to Eclipse; there's also an RCP flavor of it that doesn't rely on
there being a workspace.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
I am planning to store large amount of data. I fear that the standard
XMI serialization may lead to long loading/saving times ?</pre>
</blockquote>
Massively large files as opposed to a larger number of smaller files
are generally something to avoid.&nbsp; I.e., it's better to decompose your
data into reasonable size units.&nbsp; This is true no matter what
technology you use, i.e., even DOM will not be happy with massively
large files.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap=""> Is EMF
accessing lazily to stored object ? Is Hibernate (or any database driven
solution) better for large amount of data ?
</pre>
</blockquote>
Even purely XMI-based loading is lazy in the sense of only loading a
single resource and not loading referenced resources until you need to
access the data in them.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
Should I limit the use of EMF for my pure-data layer or is it
recommended to generalize the usage to the whole project ?
</pre>
</blockquote>
I can't imagine somewhere that it would not (and I usually have a
pretty good imagination)<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
I also miss newcomer friendly blogs or tutorials out of the eclipse
documentation. Beside of this newsgroup, where should I search for
proper coding/usage standards or examples for EMF ?
</pre>
</blockquote>
All things EMF are on the documentation page accessible from the
navigation bar on the home page.&nbsp; I love reading the blogs on the
planet:
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
How will EMF react if I try to load serialized data from a previous
model with a newly generated source code ?</pre>
</blockquote>
You mean after the model as changed?&nbsp; If the changes are binary
compatible, it should be fine.&nbsp; There even load options to support
forward compatibility, i.e., that would allow an older model to read a
newer serialization.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap=""> Both with minor updates (new
properties) to major changes (new object relationship, interfaces,
removed objets...) What is the standard way to work in order to support
data model upgrade ?
</pre>
</blockquote>
The additions are easy to handle so that won't be a problem.&nbsp; Removal
is obviously tricky, but, as I said, there is a load option to help:<br>
<blockquote><small>&nbsp; /**<br>
&nbsp;&nbsp; * This options allows you to record unknown features during
deserialization/loading.<br>
&nbsp;&nbsp; * The default is &lt;code&gt;Boolean.FALSE&lt;/code&gt; unless set
to &lt;code&gt;Boolean.TRUE&lt;/code&gt; explicitly. <br>
&nbsp;&nbsp; * The unknown features and their values can be accessed via
getEObjectToExtensionMap().<br>
&nbsp;&nbsp; * @see #getEObjectToExtensionMap()&nbsp; <br>
&nbsp;&nbsp; */<br>
&nbsp; String OPTION_RECORD_UNKNOWN_FEATURE = "RECORD_UNKNOWN_FEATURE";</small><br>
</blockquote>
The recorded information can be post processed to throw it away if
that's the desired effect.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
I'd like to generate my data objects from xml configuration using
factory patterns. I'd also like to update existing object from new
configuration features from one public code release to another. Should I
extend the emf package factory class content or define factory/updater
object outside of emf ?
</pre>
</blockquote>
I'm not sure what this question is driving at.&nbsp; EMF is a merging
generator, so when you change the model, you just regenerate and what
you need shows up.<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
Is anyone knows if the Maven team is going to support (up to date)
eclipse jars (emf mainly) rather than forcing me to use the
(undocumented) emf repository ?
</pre>
</blockquote>
I believe Nick is already producing maven results for each build, but&nbsp;
I don't know where he's "hiding" them.<br>
<br>
<blockquote cite="mid:g4e9d5$ben$1@build.eclipse.org" type="cite">
<pre wrap="">
I guess that's enough for my first post. I don't expect complete
explanations for all of this but general indications for me to getting
started with that beautiful tool.

Thanks in advance for your help !

Guillaume
</pre>
</blockquote>
</body>
</html>

--------------000402010105070700050903--


Ed Merks
Professional Support: https://www.macromodeling.com/
Re: Getting started with EMF [message #420587 is a reply to message #420577] Wed, 02 July 2008 19:40 Go to previous messageGo to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Ed Merks a écrit :
> Guillaume,
>
> It's gratifying to see lots of folks helped answer your questions. I
> think this gives you a sense of what a great community has built up in
> the modeling space at Eclipse. More comments below.

Yes that's really enjoyable ! I thank you all for this first discussion.

>> - Modeling my objects data and relationship in an UML way
>>
> I suppose so, but you could model them using XML Schema instead, though
> XML Schema is deficient in a number of important ways, including the
> ability to specify strongly typed non-containment references; EMF
> support schema annotations to overcome these limitations.

In fact I only used the EMF ecore editor and genmodels so far. Is that
enough ?

>> It is say
>> that is possible to use it in a standalone context, there is maybe a
>> more convenient way to use it through a framework maybe ?
>>
> The core runtime and edit support are designed such that the plugin jars
> can be used as jars on the classpath with no other Eclipse dependencies
> on the classpath.

My project uses (excerpt from my POM) :
<artifactId>ecore-xmi</artifactId>
<artifactId>ecore-change</artifactId> <artifactId>ecore</artifactId>
<artifactId>common</artifactId>

/home/guibod/.m2/repository/org/eclipse/emf/ecore-xmi/2.3.2/ ecore-xmi-2.3.2.jar
/home/guibod/.m2/repository/org/eclipse/emf/ecore-change/2.3 .0/ecore-change-2.3.0.jar
/home/guibod/.m2/repository/org/eclipse/emf/ecore/2.3.2/ecor e-2.3.2.jar
/home/guibod/.m2/repository/org/eclipse/emf/common/2.3.2/com mon-2.3.2.jar

That's enough I guess.

>> Is anyone knows if the Maven team is going to support (up to date)
>> eclipse jars (emf mainly) rather than forcing me to use the
>> (undocumented) emf repository ?
>>
> I believe Nick is already producing maven results for each build, but
> don't know where he's "hiding" them.

No he's not. I already have a word about this with Nick. That's quite a
mess regarding Eclipse packages at Maven. Nick files are neat and I use
them with GREAT pleasure.

>> My genmodel removes edit and editor classes since that's really eclipse
>> related features, am I right ?
>>
> The edit stuff is independent of Eclipse and might be used to build a
> swing-based application (someone is writing an article about having done
> that) or it might be used in a web-based context. The editor is tied to
> Eclipse; there's also an RCP flavor of it that doesn't rely on there
> being a workspace.

Good to know that. I'll look forward using the "edit" source generation.

>> Should I limit the use of EMF for my pure-data layer or is it
>> recommended to generalize the usage to the whole project ?
>>
> I can't imagine somewhere that it would not (and I usually have a pretty
> good imagination)

This is the main point of this conversation for me. I already coded the
basis of my server and looking forward adding data support. You suggest
me that I should go to a fully EMF driven project ?

>> Both with minor updates (new
>> properties) to major changes (new object relationship, interfaces,
>> removed objets...) What is the standard way to work in order to support
>> data model upgrade ?
>>
> The additions are easy to handle so that won't be a problem. Removal is
> obviously tricky, but, as I said, there is a load option to help:
>
> /**
> * This options allows you to record unknown features during
> deserialization/loading.
> * The default is <code>Boolean.FALSE</code> unless set to
> <code>Boolean.TRUE</code> explicitly.
> * The unknown features and their values can be accessed via
> getEObjectToExtensionMap().
> * @see #getEObjectToExtensionMap()
> */
> String OPTION_RECORD_UNKNOWN_FEATURE = "RECORD_UNKNOWN_FEATURE";
>
> The recorded information can be post processed to throw it away if
> that's the desired effect.

Great. Thanks for the tip.

>> I'd like to generate my data objects from xml configuration using
>> factory patterns. I'd also like to update existing object from new
>> configuration features from one public code release to another. Should I
>> extend the emf package factory class content or define factory/updater
>> object outside of emf ?
>>
> I'm not sure what this question is driving at. EMF is a merging
> generator, so when you change the model, you just regenerate and what
> you need shows up.

Well to be honest I both discover the pleasure to develop in Java
language. I am not used with proper code organization in this language.
Of course I was aware of the @generated keywords and the ability to
merge both human code from automatically generated sources.

This is a direct effect from my reluctance from applying EMF for my
whole project. I don't really know if i should both handle in EMF my
pure data objects and my server or controllers classes. That's maybe a
conceptual error from my side.
In my head, I only define a data model in EMF and use it with controller
methods.

I guess it is not difficult to use EMF to create an ecore from my actual
sources or something like this ?

Guillaume
Re: Getting started with EMF [message #420588 is a reply to message #420587] Wed, 02 July 2008 20:28 Go to previous messageGo to next message
Ed Merks is currently offline Ed MerksFriend
Messages: 33113
Registered: July 2009
Senior Member
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Guillaume,

Comments below.


Guillaume Boddaert wrote:
> Ed Merks a


Ed Merks
Professional Support: https://www.macromodeling.com/
Re: Getting started with EMF (what about CDO) [message #420589 is a reply to message #420533] Wed, 02 July 2008 20:34 Go to previous messageGo to next message
Eclipse UserFriend
Originally posted by: guibod.users.sf.net

Eike Stepper a écrit :
> Hi Guillaume,
>
> CDO aims to be a complete model repository solution and an extensible
> framework for distributed, shared, transaction and persistent models.
> It covers the whole stack from the client (possibly) over the network
> down to a central model repository with exchangeable back-end support.
> Hibernate and Martin's Teneo for automatic mapping is also supported on
> the server side.
>
> Please have a look at the wiki http://wiki.eclipse.org/CDO and check out
> my EclipseCon presentation:
> http://www.eclipsecon.org/2008/index.php?page=sub/&id=58
>
> Of course you're also welcome to ask more detailed questions here ;-)
>
> Cheers
> /Eike

I took the time to read CDO presentation slides. That's really exciting
! However I have some questions regarding some facts from the the slides.

1- The powerpoint states that there is no Lazy loading of instances on
standard EMF and a bad lazy management of lists. Furthermore, it pretend
that there are garbage collector issues.
Is it true or exaggerated in any way ?

2- Does CDO provide Maven packages as EMF project does ?

3- Is CDO stable (for standard features and -say- HSQLDB/MySQL
serialization) ? Is it popular, will it continue to evolve ?

4- Dynamic model support means that i can create a repository, send a
ecore to the server and run it ?

5- An embedded CDO server can serve itself but also clients on the network ?

6- How CDO reacts with model changes ? With both new elements and
elements removed. Ed Merks introduced me to the
OPTION_RECORD_UNKNOWN_FEATURE feature from EMF, is it supported ?


In fact I like the transaction and the multi resource capabilities. It
fit my project needs where a game server serves multiples game instances
with serialized data from one round to another. It would allow me to
start a single CDO data server for all instance (and not one independant
EMF resourceset by game instance).
I don't want to choice the bad serialization/modeling tool for my
project. I need both a tool that i can overcome quickly, that fit my
needs and that is promised to a bright future.

Guillaume
Re: Getting started with EMF (what about CDO) [message #420598 is a reply to message #420589] Thu, 03 July 2008 10:03 Go to previous messageGo to next message
Andre Dietisheim is currently offline Andre DietisheimFriend
Messages: 131
Registered: July 2009
Senior Member
Hi Guillaume

I started using CDO in May, so Im no big expert yet, but I might hand
out some of my limited experiences:

Guillaume Boddaert wrote:
> 1- The powerpoint states that there is no Lazy loading of instances on
> standard EMF and a bad lazy management of lists. Furthermore, it pretend
> that there are garbage collector issues.
> Is it true or exaggerated in any way ?

I did not dig this issue yet, but I can share some of my thoughts on this:
I experienced proxy-resolution when executing ECoreUtil#equals on
instances and I assume this is the limited proxy resolution Eike talks of.
Currently you have to load the whole model in the client to manipulate
the object graph. Performance improvements are expected with a
server-side query mechanism for CDO 2.0. This allows you to load parts
of the model only. The queries may then be formulated in OCL, HSQL, etc.

233273: [QUERY] Develop Query mechanism
https://bugs.eclipse.org/bugs/show_bug.cgi?id=233273

>
> 2- Does CDO provide Maven packages as EMF project does ?
>

I did not find any yet, but I offered our help here (we might join efforts?)

> 3- Is CDO stable (for standard features and -say- HSQLDB/MySQL
> serialization) ? Is it popular, will it continue to evolve ?
>

We implemented a proof-of-concept in a client-server (standalone
CDO-server, RCP client) and we experienced big issues (we could solve
all of them with affordable efforts). We were very pleased to see how
far things are ready already, even up to locking issues etc. The only
part which needs some serious efforts (although things already work out
of the box) is - in my opinion - the client.

> 4- Dynamic model support means that i can create a repository, send a
> ecore to the server and run it ?

I'm no big connaisseur yet but as far as I understand this dynamic means
dynamic/static EMF models here. You may use generated EMF-models and
dynamically built ones.
We focussed on generated ones and there is no need to rebuild nor
restart the server in this scenario. The new model(-plugin) just has to
be accessible to the (generic) client. You just register the new model
in a new session and there you are. I assume that you don't even have to
restart the client if you use a proper OSIG-Service-consumer/provider
scheme with static models or if you use dynamically created models.
It looks like there's the necessity to migrate the db after any model
change. We did not try this yet, we simply dropped the existing db.

>
> 5- An embedded CDO server can serve itself but also clients on the network ?
>

absolutely.

> 6- How CDO reacts with model changes ? With both new elements and
> elements removed. Ed Merks introduced me to the
> OPTION_RECORD_UNKNOWN_FEATURE feature from EMF, is it supported ?
>

I don't have a clue what this feature is, sorry... ;-(

>
> In fact I like the transaction and the multi resource capabilities. It
> fit my project needs where a game server serves multiples game instances
> with serialized data from one round to another. It would allow me to
> start a single CDO data server for all instance (and not one independant
> EMF resourceset by game instance).
> I don't want to choice the bad serialization/modeling tool for my
> project. I need both a tool that i can overcome quickly, that fit my
> needs and that is promised to a bright future.
>
> Guillaume


Cheers
André
Re: Getting started with EMF (what about CDO) [message #420601 is a reply to message #420598] Thu, 03 July 2008 11:36 Go to previous message
Andre Dietisheim is currently offline Andre DietisheimFriend
Messages: 131
Registered: July 2009
Senior Member
sorry, mistyped... we experienced not big issue at all :-)

André Dietisheim wrote:
> Hi Guillaume
>
> I started using CDO in May, so Im no big expert yet, but I might hand
> out some of my limited experiences:
>
> Guillaume Boddaert wrote:
>> 1- The powerpoint states that there is no Lazy loading of instances on
>> standard EMF and a bad lazy management of lists. Furthermore, it pretend
>> that there are garbage collector issues.
>> Is it true or exaggerated in any way ?
>
> I did not dig this issue yet, but I can share some of my thoughts on this:
> I experienced proxy-resolution when executing ECoreUtil#equals on
> instances and I assume this is the limited proxy resolution Eike talks of.
> Currently you have to load the whole model in the client to manipulate
> the object graph. Performance improvements are expected with a
> server-side query mechanism for CDO 2.0. This allows you to load parts
> of the model only. The queries may then be formulated in OCL, HSQL, etc.
>
> 233273: [QUERY] Develop Query mechanism
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=233273
>
>>
>> 2- Does CDO provide Maven packages as EMF project does ?
>>
>
> I did not find any yet, but I offered our help here (we might join
> efforts?)
>
>> 3- Is CDO stable (for standard features and -say- HSQLDB/MySQL
>> serialization) ? Is it popular, will it continue to evolve ?
>>
>
> We implemented a proof-of-concept in a client-server (standalone
> CDO-server, RCP client) and we experienced big issues (we could solve
> all of them with affordable efforts). We were very pleased to see how
> far things are ready already, even up to locking issues etc. The only
> part which needs some serious efforts (although things already work out
> of the box) is - in my opinion - the client.
>
>> 4- Dynamic model support means that i can create a repository, send a
>> ecore to the server and run it ?
>
> I'm no big connaisseur yet but as far as I understand this dynamic means
> dynamic/static EMF models here. You may use generated EMF-models and
> dynamically built ones.
> We focussed on generated ones and there is no need to rebuild nor
> restart the server in this scenario. The new model(-plugin) just has to
> be accessible to the (generic) client. You just register the new model
> in a new session and there you are. I assume that you don't even have to
> restart the client if you use a proper OSIG-Service-consumer/provider
> scheme with static models or if you use dynamically created models.
> It looks like there's the necessity to migrate the db after any model
> change. We did not try this yet, we simply dropped the existing db.
>
>>
>> 5- An embedded CDO server can serve itself but also clients on the
>> network ?
>>
>
> absolutely.
>
>> 6- How CDO reacts with model changes ? With both new elements and
>> elements removed. Ed Merks introduced me to the
>> OPTION_RECORD_UNKNOWN_FEATURE feature from EMF, is it supported ?
>>
>
> I don't have a clue what this feature is, sorry... ;-(
>
>>
>> In fact I like the transaction and the multi resource capabilities. It
>> fit my project needs where a game server serves multiples game instances
>> with serialized data from one round to another. It would allow me to
>> start a single CDO data server for all instance (and not one independant
>> EMF resourceset by game instance).
>> I don't want to choice the bad serialization/modeling tool for my
>> project. I need both a tool that i can overcome quickly, that fit my
>> needs and that is promised to a bright future.
>>
>> Guillaume
>
>
> Cheers
> André
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