The best option is to:
* fix the system bundle capabilities
* use a dependency feature as you did
To fix the system bundle capabilities, depending on the framework used, you
can do something along the following:
org.osgi.framework.system.capabilities=\
...\
${${framework}-capabilities}
felix-capabilities=
equinox-capabilities=\
osgi.service;effective:=active;objectClass=javax.xml.parsers.
SAXParserFactory
I haven't tested the above, but hopefully you'll get the idea. It's
similar to what's done for the ${jre-${java.specification.version}}...
2017-02-06 9:16 GMT+01:00 Markus Rathgeb <maggu2...@gmail.com>:
> Hi Guillaume,
> thank you for your reply.
>
> In this special case it is about an implementation for
> "javax.xml.parsers.SAXParserFactory" and a service for that.
> The bundle "org.eclipse.equinox.registry" (I need to use to satisfy
> third party dependencies) is using a tracker to find an implementation
> and prints errors to stdout if there is no one.
> To prevent that messages on every Karaf start I would like to have
> such a service in the Karaf instance.
>
> The Equinox OSGi framework provides that service itself. Without any
> provide capability in its manifest.
> The Apache Felix OSGi framework doesn't provide such a service.
>
> So, what are the options:
>
> add it to "org.osgi.framework.system.capabilities"
> IMHO this will be not correct, because the service is present if
> Equinox is used and not present if Felix is used.
>
> Use "conditionals" in a feature to install another bundle that
> provides a "javax.xml.parsers.SAXParserFactory" service if Felix is
> used (and so the conditional will skip the installation if Equinox is
> used).
> If my reading has been correct, conditionals could be used for
> installed features and not for the special OSGi framework
> implementation.
>
> I can install another bundle / feature that provides that service
> implementation for both frameworks.
> This is okay, but if it is not necessary...
>
> So, is there a simple method to leave it up to the user to switch
> between "karaf.framework" Felix or Equinox and handle that in some
> way, so another implementation is installed only if not Equinox is
> choosen?
>
> Best regards,
> Markus
>
> 2017-02-06 8:45 GMT+01:00 Guillaume Nodet <gno...@apache.org>:
> > You can modify the etc/config.properties file, in particular the
> > org.osgi.framework.system.capabilities
> > configuration. If some service are provided by default by the framework
> and
> > are missing,
> > you may want to raise a JIRA issue and provide a patch / pull request.
> >
> > 2017-02-05 12:05 GMT+01:00 Markus Rathgeb <maggu2...@gmail.com>:
> >>
> >> Ah, okay, I assume it is caused by the missing
> >> Provide-Capability of the Equinox bundle that it provides that service.
> >> Could this information be added by some configuration file without
> >> modify the Equinox bundle itself?
> >>
> >> 2017-02-05 11:49 GMT+01:00 Markus Rathgeb <maggu2...@gmail.com>:
> >> > Hello,
> >> >
> >> > I thought I understand how the dependency flag is working for features
> >> > and bundles, but at least it seems to be different.
> >> > Perhaps someone could explain me the following scenario:
> >> >
> >> > Feature file:
> >> > ===
> >> > <?xml version="1.0" encoding="UTF-8"?>
> >> > <features name="saxparserfactory"
> >> > xmlns="http://karaf.apache.org/xmlns/features/v1.4.0";>
> >> >
> >> > <feature name="saxparserfactory" version="1.0-SNAPSHOT">
> >> >
> >> > <requirement>osgi.service;filter:="(objectClass=javax.
> xml.parsers.SAXParserFactory)";effective:=active</requirement>
> >> > <feature dependency="true">jboss-xerces</feature>
> >> > </feature>
> >> >
> >> > <feature name="jboss-xerces" description="JBoss Xerces"
> >> > version="1.0-SNAPSHOT">
> >> > <details>OSGi service for
> >> > 'javax.xml.parsers.SAXParserFactory'</details>
> >> >
> >> > <!-- Maven repository:
> >> > https://repository.jboss.org/nexus/content/repositories/releases/ -->
> >> > <!-- <bundle
> >> >
> >> > start-level="30">mvn:org.jboss.osgi.xerces/jbosgi-
> xerces/3.1.0.Final</bundle>
> >> > -->
> >> > <bundle
> >> > start-level="30">https://repository.jboss.org/nexus/
> content/repositories/releases/org/jboss/osgi/xerces/jbosgi-
> xerces/3.1.0.Final/jbosgi-xerces-3.1.0.Final.jar</bundle>
> >> >
> >> > <capability>osgi.service;objectClass=javax.xml.parsers.
> SAXParserFactory</capability>
> >> >
> >> > <bundle dependency="true"
> >> > start-level="30">mvn:org.osgi/org.osgi.util.xml/1.0.1</bundle>
> >> > <bundle dependency="true"
> >> > start-level="8">mvn:org.ops4j.pax.logging/pax-logging-api/1.
> 9.1</bundle>
> >> > </feature>
> >> >
> >> > </features>
> >> > ===
> >> >
> >> > I would expect if I install the feature "saxparserfactory" the feature
> >> > jboss-xerces is installed only if the requirements are not already
> >> > fulfilled.
> >> > The only requirement the feature drops in should be to ensure that
> >> > there is a SAXParserFactory service available.
> >> > Should this be possible?
> >> >
> >> >
> >> > Test
> >> > ===
> >> >
> >> > I used the current Karaf 4.1.0 form the second voting round.
> >> >
> >> > Start a clean instance:
> >> > $ bin/karaf clean
> >> >
> >> > As expected Apache Felix is the used OSGi framework
> >> >
> >> > karaf@root()> bundle:list -t 0 -s 0 | grep Active
> >> > 0 │ Active │ 0 │ 5.6.1 │ org.apache.felix.framework
> >> >
> >> > I added the feature repository file.
> >> >
> >> > karaf@root()> feature:repo-add
> >> > file:///home/maggu2810/tmp/saxparserfactory-feature.xml
> >> > Adding feature url
> >> > file:///home/maggu2810/tmp/saxparserfactory-feature.xml
> >> >
> >> > After that let's look if there is already a SAXParserFactory present:
> >> >
> >> > karaf@root()> service:list javax.xml.parsers.SAXParserFactory
> >> >
> >> > No output, so as expected, no service found.
> >> >
> >> > Check what will be done if the feature is installed:
> >> >
> >> > karaf@root()> feature:install -t -v saxparserfactory
> >> > Adding features: saxparserfactory/[1.0.0.SNAPSHOT,1.0.0.SNAPSHOT]
> >> > Changes to perform:
> >> > Region: root
> >> > Bundles to install:
> >> >
> >> > https://repository.jboss.org/nexus/content/repositories/
> releases/org/jboss/osgi/xerces/jbosgi-xerces/3.1.0.
> Final/jbosgi-xerces-3.1.0.Final.jar
> >> > mvn:org.osgi/org.osgi.util.xml/1.0.1
> >> >
> >> > This is as I expect what should be done.
> >> >
> >> > Let's exit the Karaf container.
> >> >
> >> > karaf@root()> shutdown -f
> >> >
> >> >
> >> >
> >> > After that I used the Equinox framework
> >> >
> >> > $ echo 'karaf.framework=equinox' >> etc/custom.properties
> >> >
> >> > and started again a clean isntance.
> >> >
> >> > $ bin/karaf clean
> >> >
> >> > Ensure the feature repository is available:
> >> >
> >> > karaf@root()> feature:repo-add
> >> > file:///home/maggu2810/tmp/saxparserfactory-feature.xml
> >> > Adding feature url
> >> > file:///home/maggu2810/tmp/saxparserfactory-feature.xml
> >> >
> >> > The Equinox OSGi framework bundle already provides a SAXParserFactory
> >> > service.
> >> >
> >> > karaf@root()> service:list javax.xml.parsers.SAXParserFactory
> >> > [javax.xml.parsers.SAXParserFactory]
> >> > ------------------------------------
> >> > service.pid =
> >> > 0.org.eclipse.osgi.internal.framework.XMLParsingServiceFactory
> >> > service.vendor = Eclipse.org - Equinox
> >> > service.id = 20
> >> > service.bundleid = 0
> >> > service.scope = bundle
> >> > Provided by :
> >> > OSGi System Bundle (0)
> >> >
> >> > Now I would expect that the installation of the saxparserfactory
> >> > feature will not trigger an installation of the jboss-xerces feature,
> >> > because all requirements should be already satisfied.
> >> > But it looks like:
> >> >
> >> > karaf@root()> feature:install -t -v saxparserfactory
> >> > Adding features: saxparserfactory/[1.0.0.SNAPSHOT,1.0.0.SNAPSHOT]
> >> > Changes to perform:
> >> > Region: root
> >> > Bundles to install:
> >> >
> >> > https://repository.jboss.org/nexus/content/repositories/
> releases/org/jboss/osgi/xerces/jbosgi-xerces/3.1.0.
> Final/jbosgi-xerces-3.1.0.Final.jar
> >> > mvn:org.osgi/org.osgi.util.xml/1.0.1
> >> >
> >> > What am I doing wrong?
> >> >
> >> > Best regards,
> >> > Markus Rathgeb
> >
> >
> >
> >
> > --
> > ------------------------
> > Guillaume Nodet
> >
>
--
------------------------
Guillaume Nodet
