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https://issues.apache.org/jira/browse/STANBOL-996?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rupert Westenthaler resolved STANBOL-996.
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Resolution: Fixed
marking as fixed as all sub-tasks are resolved.
> Seperate OSGI Services and Components for the Entityhub
> -------------------------------------------------------
>
> Key: STANBOL-996
> URL: https://issues.apache.org/jira/browse/STANBOL-996
> Project: Stanbol
> Issue Type: Bug
> Components: Entityhub
> Affects Versions: entityhub-0.11.0
> Reporter: Rupert Westenthaler
> Assignee: Rupert Westenthaler
>
> Currently most Entityhub components are both OSGI services and components
> (meaning that they have both the @Service and @Component annotation).
> Affected:
> * ReferencedSite
> * Cache
> * SolrYard
> Not Affected:
> * ManagedSite: This component uses already the described model
> * ClerezzaYard: No external dependencies
> Why to separate @Component and @Service implementations
> ================================================
> A detailed description of the design can be found in [1].
> The main reason for adopting this model for the Entityhub is not to provide
> its services outside of OSGI, but to solve the problem of registered services
> with missing dependencies (e.g. A SolrYard that is still missing the
> configured SolrServer).
> The new model will allow to
> * check in the activate method of the Component if the user provided
> configuration is valid
> * init and open serviceTracker for the referenced services
> * mark the component as activated
> but only as soon as all tracked services do become available the Service
> would be instantiated and registered with the OSGI environment.
> With this model Entityhub services (e.g. the RESTful API for a
> ReferencedSite) would only become available if the site is ready to use. With
> the current architecture this is the case as soon as the activate method of
> the component completes. Because of this Users do get Exceptions like
> (example taken from [2])
> java.lang.IllegalStateException: Unable to initialize the Cache with Yard
> netzmuehleIndex!
> This is usually caused by Errors while reading the Cache Configuration
> from the Yard.
> at
> org.apache.stanbol.entityhub.core.site.CacheImpl.getCacheYard(CacheImpl.java:214)
> [..]
> Caused by: org.apache.stanbol.entityhub.servicesapi.yard.YardException:
> TheSolrIndex
> 'netzmuehle' for SolrYard 'netzmuehle Index' is currently not active!
> at
> org.apache.stanbol.entityhub.yard.solr.impl.SolrYard.getServer(SolrYard.java:512)
> [..]
> Backward Compatibility
> ==================
> The new design will require to add new '{service}Component' classes (e.g.
> SolrYardComponent, ReferencedSiteComponent). Why those will take the same
> configurations as the current {service}s OSGI would - by default - assume the
> configuration files to be named after the Class name. This would mean that
> current configuration files would no longer be considered by the new
> '{service}Component's.
> To avoid this and provide full backward compatibility the 'name' parameter of
> the new '{service}Component's need to be set to the 'name' used of the old
> {service} classes.
>
> [1] http://markmail.org/thread/yw6l5pnk6djovcjy
> [2] http://markmail.org/message/7etfzzhicsuh26m4
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