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https://issues.apache.org/jira/browse/SLING-5041?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15070964#comment-15070964
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Konrad Windszus commented on SLING-5041:
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This is my proposal on how to fix this:
# Deprecate {{ServiceUtil.getComparableForServiceRankings()}} and instead add
two methods {{ServiceUtil.getComparableForServiceRankingsHighestFirst()}} and
{{ServiceUtil.getComparableForServiceRankingsLowestFirst()}}. The latter is
also called by the deprecated method
{{ServiceUtil.getComparableForServiceRankings()}}.
The javadoc of both methods should clarify, when to use which comparable. The
former is useful for implementing an order similar to what is used by
{{BundleContext.getServiceReference()}}, i.e. highest rank first. I am not
quite sure for what purpose you would need the latter though but we need it to
be backwards-compatible (lowest rank first).
# For {{RankedServices}} itself I would rather go for incrementing the package
version to 3.0 and just fix the iterator order from ascending to descending
(i.e. highest first) by internally relying on the new
{{ServiceUtil.getComparableForServiceRankingsHighestFirst()}}. The way it is
implemented right now is really not that useful and rather contradicts OSGi
rules.
The alternative would be to deprecate {{RankedServices}} and introduce a new
interface {{OSGiCompliantRankedServices}} which inverts the order.
[[email protected]][~cziegeler][[~bdelacretaz] WDYT? Which way would you
prefer?
> Clarify the order of the iterator given by RankedServices
> ---------------------------------------------------------
>
> Key: SLING-5041
> URL: https://issues.apache.org/jira/browse/SLING-5041
> Project: Sling
> Issue Type: Improvement
> Components: Commons
> Affects Versions: Commons OSGi 2.3.0
> Reporter: Konrad Windszus
>
> Currently the iterator in {{RankedServices}} returns the services in the
> ascending order from lowest to highest ranking. This is a different order
> then being used by OSGi internally [1]. Usually you are only interested in an
> iterator which gives you the service with the highest ranking first (because
> that would also be the one being returned by
> {{BundleContext.getServiceReference(...)}}).
> If we don't change the iterator logic we should at least make it clearer in
> the Javadoc that the iterator really gives the services in ascending order of
> their service ranking property and we should probably add a more useful
> iterator which gives back the services with the highest ranking first.
> The issue came up in the context of SLING-5035.
> [1] -
> https://osgi.org/javadoc/r4v42/org/osgi/framework/BundleContext.html#getServiceReference(java.lang.String)
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