[jira] [Commented] (OAK-2273) Export Lucene packages

["Felix Meschberger (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/OAK-2273?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14219385#comment-14219385 ] 

Felix Meschberger commented on OAK-2273:
----------------------------------------

I had a quick chat with [~chetanm] on this topic.

Considering:

* oak-lucene provides its own Codec implementation for Lucene
* Lucene loads the Codecs using Java Service Loader (and never unloads)
* thus a separate Lucene bundle would not see the oak-lucene Codec since the Lucene bundle Service Loader does not know about OSGi
* thus Lucene better be embedded in oak-lucene such that the Lucene Service Loader sees the oak-lucene codec and code loading is bound to the livecycle of oak-lucene
* another bundle in the framework could export Lucene as well but oak-lucene must use its own version and not wire to that other bundle

I suggest to

* export the org.apache.lucene packages with just the version number of the lucene library; e.g.
{noformat}
Export-Package:
    org.apache.lucene.*; version=4.7.1
{noformat}
* not import org.apache.lucene packages. This guarantess that oak-lucene itself always only uses the embedded lucene packages; e.g.
{noformat}
Import-Package:
    !org.apache.lucene.*,
    *
{noformat}

The worst thing that could happen in this scenario is that an importer of a lucene package and providing an Analyzer is not wired to oak-lucene and thus oak-lucene cannot use that Analyzer service

> Export Lucene packages 
> -----------------------
>
>                 Key: OAK-2273
>                 URL: https://issues.apache.org/jira/browse/OAK-2273
>             Project: Jackrabbit Oak
>          Issue Type: Sub-task
>          Components: oak-lucene
>            Reporter: Chetan Mehrotra
>            Assignee: Chetan Mehrotra
>             Fix For: 1.2
>
>
> As discussed in [1] for enabling custom analyzers in Oak we intend make use of OSGi ServiceRegistry. This would require other bundles to create custom analyzer instance and register it with SR from where oak-lucene would look them up
> Further export would make use of Mandatory Attributes so as to prevent Oak usage of Lucene affecting other bundles in the OSGi runtime. The Lucene packages would be exported like
> {noformat}
> Export-Package: org.apache.lucene;provider="oak";mandatory=:provider
> {noformat}
> And any bundle which wish to make use of Lucene related packages
> {noformat}
> Import-Package : org.apache.lucene;provider="oak"
> {noformat}
> [1] http://markmail.org/thread/xsmg3tjjbkhtyhpk#query:+page:1+mid:jmip66k43l2qxc6a+state:results
> [2] http://www.osgi.org/download/r4v41/r4.core.pdf (Sec 3.6.6 pg 45)



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