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Re: [] RE: [cross-project-issues-dev] Feedback on the europa update site

I would like to try to shed some light on two relationships supported by
Update Manager: 'includes' and 'requires':

   When a feature 'includes' another feature, it makes it part of its
   hierarchy. Including represents aggregation - included features are
   building blocks of the root feature. If only the root feature is
   interesting to the end-users, only the root feature should be exposed in
   A feature may also 'require' another feature, which implies
   precondition. The required feature is not part of the depending feature
   hierarchy but is a precondition for the feature to be installed.

Here is how 'Select Required' works: it will try to find the required
feature listed explicitly in site.xml. If that fails, it will try to find
the explicitly listed feature that INCLUDES the desired feature and select
it instead. If more than one candidate is found, 'Select Required' will
pick one that is smaller.

When only a few features are listed in site.xml, the effect is similar to
option bundles when car shopping - in order to get the sunroof, you must
buy the 'luxury' package with leather and alloy wheels :-). On the other
hand, listing ALL the features in site.xml may be too confusing to people.

I recommend to focus on what most people will want from Europa - pick some
high-value feature combinations and expose them in site.xml. If my feature
Foo requires something from EMF that is not explicitly listed in site.xml,
it will pick the smallest EMF 'root' feature that includes it. The overhead
(additional features I didn't ask for) is not a problem as long as it is
not significant.


Dejan Glozic, Ph.D.
Manager, Eclipse Development 1A
IBM Canada Ltd.
Tel. 905 413-2745  T/L 969-2745
Fax. 905 413-4850

             06/04/2007 01:18          ""      
             PM                        < 
                                       "Cross project issues"              
                                       rg>, Dejan Glozic/Toronto/IBM@IBMCA 
                                       Re: []  
                                       RE: [cross-project-issues-dev]      
                                       Feedback on the europa update site  
                                       (Document link: Dejan Glozic)       

As an example, the EMF-QTV components are contributed to Europa as a pair
of features:

    Eclipse Modeling Framework Data Integrity Frameworks Extender SDK
    Eclipse Modeling Framework Data Integrity Frameworks End-User Features

Both of these comprise, respectively, the SDK and Run-time features of
these three distinct components, to roll them into one.

Each component individually has two run-time features, so that the
all-in-one run-time Europa feature contains:

       - org.eclipse.emf.query
       - org.eclipse.emf.query.ocl
       - org.eclipse.emf.transaction
       - org.eclipse.emf.workspace
       - org.eclipse.emf.validation
       - org.eclipse.emf.validation.ocl

where nesting shows <include>ed features.  None of these six included
features is listed in the Europa site.xml.  If these features had, instead,
been prereqed via <requires> at either the feature or plug-in level, then I
think it may have been necessary to expose them in the site.xml.

AFAIK, update manager has no problem with multiple features <include>ing
the same features, so perhaps <include> can be used more extensively to
avoid filling up the site.xml.

Hope that helps to clarify,


Christian W. Damus
Component Lead, Eclipse OCL and EMF-QTV
IBM Rational Software

             <Martin.Oberhuber                                          To 
   >           "Cross project issues"              
             Sent by:                  <cross-project-issues-dev@eclipse.o 
             ing-council-bounc                                          cc 
             es@xxxxxxxxxxx            Dejan Glozic/Toronto/IBM@IBMCA,     
             06/04/07 12:44 PM>                             
                                       [] RE:  
             Please respond to         [cross-project-issues-dev]          
             "         Feedback on the europa update site  

My memory might fool me, but I think that my experience has shown me so
far, that
"Select Required" does NOT work for features which are available on the
site but not
listed on site.xml . After all, UM would not be able to display a selection
for such
features, would it? And, how would it know that these features exist after
all? I don't
think it scans the remote directory, I even don't think it would be capable
of doing that
through the http: protocol.

I have no time to verify this again now, but I'd recommend Bjorn to wait
with changes
to the build system until someone has verified what "Select Required" does.

Perhaps Dejan knows off the top of his head?

Martin Oberhuber
Wind River Systems, Inc.
Target Management Project Lead, DSDP PMC Member

 From: cross-project-issues-dev-bounces@xxxxxxxxxxx
 [mailto:cross-project-issues-dev-bounces@xxxxxxxxxxx] On Behalf Of Jeff
 Sent: Monday, June 04, 2007 4:30 PM
 To: Cross project issues
 Cc: cross-project-issues-dev-bounces@xxxxxxxxxxx; Cross project issues;
 Subject: Re: [cross-project-issues-dev] Feedback on the europa update site

 Note that I said,
         " Of course, there may well be a reality issue blocking this
 theory... "
 Please confirm that this all works as described, expected, desired before
 going off and doing Europa-wide changes.


 Bjorn Freeman-Benson                                                      
 <bjorn.freeman-benson@ec                                          >                                                                
 Sent by:                                                               To 
 cross-project-issues-dev       Cross project issues                       
 -bounces@xxxxxxxxxxx           <cross-project-issues-dev@xxxxxxxxxxx>,    
 06/04/2007 10:15 AM                                                    cc 
     Please respond to          Re: [cross-project-issues-dev] Feedback on 
   Cross project issues         the europa update site                     

 Hmm, I learn something new every day... Ok, I will modify the Europa build
 tool not to require that all features be listed in site.xml. I will send
 email to the list after I have done that so that any project who wishes to
 modify their portion of the site.xml may do so. Please do not modify the
 Europa site.xml until after I have fixed the Europa build tool. Thanks.

 Jeff McAffer wrote:

 Just to clarify something, to have a feature be available an installable
 from an update site it does NOT have to be listed in the site.xml.  The
 site.xml is used to show users what is available for them to select and
 download.  Depending on the workflow the features that are used by other
 projects could be put on the Europa site but not in the site.xml.  People
 should then be able to tell update manager to get the required features as
 well.  Of course, there may well be a reality issue blocking this

 Jeff _______________________________________________
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