RE: [sca-assembly] ISSUE 8: SCDL artifact resolution underspecified

["Blohm, Henning" <henning.blohm@sap.com>]

Mike,

 

  as you point out, retrieval is fast. Scanning artefacts and updating indexes often create performance problems. Many technologies therefore try to limit the scope they have to introspect by starting from some well defined scan roots (actually one of the downsides of EJB3 is the effort needed to scan classes for EJB annotations).

 

  It would be interesting to learn about what the EEG is coming up with.

 

Thanks,

  Henning

 

 

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From: Mike Edwards [mailto:mike_edwards@uk.ibm.com]
Sent: Montag, 8. Oktober 2007 17:26
To: sca-assembly@lists.oasis-open.org
Subject: RE: [sca-assembly] ISSUE 8: SCDL artifact resolution underspecified

Folks,

I tend to agree with Michael Rowley.  The assumption that artifacts are somewhere in the contribution seems a reasonable
way of limiting the search time.  

If the contribution is large and complex, it will still have to be scanned by the runtime to discover all the artifacts that need
dealing with - implementation artifacts as well as SCA metadata.   There are various techniques for handling large
contributions and making them more manageable.  Examples include Registries and Repositories which can store
the information in such a way as to make retrieval very fast.  There is an argument for saying that in any complex SCA
installation, a Registry/Repository solution is very desirable.

As for dealing with OSGi bundles and Java EE applications, well there is a group in OSGi looking at that little issue right now
in the Enterprise Expert Group....

Yours,  Mike.

Strategist - Emerging Technologies, SCA & SDO.
Co Chair OASIS SCA Assembly TC.
IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.
Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431  
Email:  mike_edwards@uk.ibm.com

"Michael Rowley" <mrowley@bea.com>

08/10/2007 16:12

To	<sca-assembly@lists.oasis-open.org>
cc
Subject	RE: [sca-assembly] ISSUE 8: SCDL artifact resolution underspecified

 
The key concern here seems to be w.r.t. performance.  In my opinion, if there is only one definition of an artifact within a contribution (as I think _should_ be the case), then it should not be necessary for a human to point at it.  Searching is one of the things that computers are good at.  Quite a large body of data can be searched in a very short time.
 
Michael
 

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From: Martin Chapman [mailto:martin.chapman@oracle.com]
Sent: Monday, October 08, 2007 9:48 AM
To: sca-assembly@lists.oasis-open.org
Subject: [sca-assembly] ISSUE 8: SCDL artifact resolution underspecified
 
Logged: http://www.osoa.org/jira/browse/ASSEMBLY-8
-----Original Message-----
From: Blohm, Henning [mailto:henning.blohm@sap.com]
Sent: Friday, October 05, 2007 8:01 PM
To: sca-assembly@lists.oasis-open.org
Subject: [sca-assembly] NEW ISSUE: SCDL artifact resolution underspecified

TARGET: Assembly specification, section "SCA Artifact Resolution" (1.10.2.1)

DESCRIPTION: Resolution of SCDL artifacts is currently specified only as far as cross-contribution export/import is concerned. As far as QName to SCDL artifact resolution within a contribution is concerned the specification does not say what is the exact scope of such resolution nor how to extend/modify that scope.

Choosing the whole contribution as resolution scope may be prohibitive considering that contributions may be large and distributed (across different execution environments) so that deep traversal of all contribution resources for scdl artifacts may easily introduce a severe performance problem and easily get out of control from a developer perspective.

As an analogy, suppose the group would perceive a contribution format that would encompass java ee applications together with OSGi bundles. Chosing a contribution wide resolution scope would correspond to chosing a contribution wide class loading scheme (which I assume all agree is highly undesirable).

On the other hand, if the resolution scope is not the whole contribution, it is necessary to allow specification of locations within a contribution.

PROPOSAL:

- use sca-contribution / import as a means to implement a namespace -> location mapping also for contribution-local artifacts

- support an scaLocation attribute to be used for namespace -> location mapping from within SCDL artifacts

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