Apache Lucene 3.1.0

[Grant Ingersoll <gs...@apache.org>]

March 2011, Apache Lucene 3.1 available
The Lucene PMC is pleased to announce the release of Apache Lucene 3.1.

This release contains numerous bug fixes, optimizations, and
improvements, some of which are highlighted below.  The release
is available for immediate download at http://www.apache.org/dyn/closer.cgi/lucene/java (see note below).
See the CHANGES.txt
file included with the release for a full list of details.

Lucene 3.1 Release Highlights

* Numerous performance improvements: faster exact PhraseQuery; merging
 favors segments with deletions; primary key lookup is faster;
 IndexWriter.addIndexes(Directory[]) uses file copy instead of
 merging; various Directory performance improvements; compound file
 is dynamically turned off for large segments; fully deleted segments
 are dropped on commit; faster snowball analyzers (in contrib);
 ConcurrentMergeScheduler is more careful about setting priority of
 merge threads.

* ReusableAnalyzerBase makes it easier to reuse TokenStreams
 correctly.

* Improved Analysis capabilities: Improved Unicode support, including
 Unicode 4, more friendly term handling (CharTermAttribute), easier
 object reuse and better support for protected words in lossy token
 filters (e.g. stemmers).

* ConstantScoreQuery now allows directly wrapping a Query.

* IndexWriter is now configured with a new separate builder API,
 IndexWriterConfig.  You can now control IndexWriter's previously
 fixed internal thread limit by calling setMaxThreadStates.

* IndexWriter.getReader is replaced by IndexReader.open(IndexWriter).
 In addition you can now specify whether deletes should be resolved
 when you open an NRT reader.

* MultiSearcher is deprecated; ParallelMultiSearcher has been
 absorbed directly into IndexSearcher.

* On 64bit Windows and Solaris JVMs, MMapDirectory is now the
 default implementation (returned by FSDirectory.open).
 MMapDirectory also enables unmapping if the JVM supports it.

* New TotalHitCountCollector just counts total number of hits.

* ReaderFinishedListener API enables external caches to evict entries
 once a segment is finished.

Note: The Apache Software Foundation uses an extensive mirroring network for distributing releases.  It is possible that the mirror you are using may not have replicated the release yet.  If that is the case, please try another mirror.  This also goes for Maven access.

--------------------------
Grant Ingersoll
Lucene Revolution -- Lucene and Solr User Conference
May 25-26 in San Francisco
www.lucenerevolution.org