[STANBOL-1440] Support SolrCore swap like feature

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.12.0
• Fix Version/s: 1.0.0, 0.12.1
• Component/s: Commons, Enhancement Engines
• Assignee: Rupert Westenthaler
• Reporter: Rupert Westenthaler
• Created: 02/Sep/15 06:23
• Updated: 09/Oct/15 06:31
• Resolved: 04/Sep/15 13:38

Description

The SolrServerAdapter warps a Solr CoreContainer and makes it and its cores available as OSGI services so that they can be used with the whiteboard pattern.

Currently when one updates a SolrCore (e.g. registering a core with the same name but a different core directory) with the SolrServerAdapter the old core is removed first and the new one only added later. This means that while on the Solr side both cores could be used simultaneously it is not possible on the OSGI side because of the order of the unregistration and registration.

This issue is about changing this so that on a SolrCore registration of an existing core the workflow is as follows

1. update the SolrCore on the CoreContainer
2. register the new SolrCore as OSGI service
3. unregister the old SolrCore as OSGI service

This issue will also update the FstLinkingEngineComponent so that the initialization can make used of the new Feature. This will avoid any EntityLinking service interruption of the SolrCore used for linking is updated.

Issue Links

• breaks: STANBOL-1442 SolrCore swap support of FSTLinkingEngine does not free old SolrCore