Can I use a single Lucene Analyzer instance for the whole search application?

Question

I'm using the latest Lucene version 5.4.

I'm curious to know if an Analyzer is stateless and a single instance can be reused by the search application instead of instantiating an Analyzer every time I need it?

I'm currently using the EnglishAnalyzer:

Analyzer analyzer = new EnglishAnalyzer();

Answer 1

Analyzers are not stateless but the reuse of an instance is intended.

Analysers are mainly the factory class for TokenStreams and in particular the EnglishAnalyzer is thread-safe. Solr loads his analysers for each SolrCore only once. So the solr-folk have trust in thread-safety of their analysers.

From the JavaDoc of tokenStream-Method :

Subsequent calls to this method will reuse the previously stored components after resetting them...

Be aware that Analysers implements "Closeable". You can not call tokenStream-Method after the close-Method was called.

PS lucene good practice and thread safety

PPS QueryParser are not threadsafe