[hibernate-dev] IndexReader caching second pair of eyes

[Emmanuel Bernard]

For Hibernate Search, I did introduce the IndexReaders caching.
My tests shows for:
  - a search intensive application,
  - low update ratio
  - in-memory database
  - filesystem based index
a speed increase of 25 to 30%.

It is not the default yet (use 'hibernate.search.reader.strategy  
shared' to enable), but once it's tested, it will be.

It was not a piece of cake (to say the least), I would appreciate a  
couple of pairs of eyes on the code, as it involves locking and JMM  
understanding.
I think I reduced the lock windows as much as possible but if  
someone's got ideas (or think it's unsafe), fell free to share.

The code is here
http://fisheye.jboss.org/browse/Hibernate/trunk/HibernateExt/search/ 
src/java/org/hibernate/search/reader/SharedReaderProvider.java?r=11576