Cache Lucene IndexReader with Apache Commons Pool

• IndexReaderFactory.java

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  package org.ostree.module.lucene;   import org.apache.commons.pool.KeyedPoolableObjectFactory; import org.apache.lucene.index.IndexReader; import org.apache.lucene.store.FSDirectory; import org.slf4j.Logger; import org.slf4j.LoggerFactory;   import java.io.File; import java.util.NoSuchElementException;   public class IndexReaderFactory implements KeyedPoolableObjectFactory<String, IndexReader> {      private String baseIndexDir= "/var/data/ostree/index" ;      private static final Logger logger = LoggerFactory              .getLogger(IndexReaderFactory. class );        public IndexReaderFactory(String baseIndexDir) {          this .baseIndexDir = baseIndexDir;      }        @Override      public IndexReader makeObject(String key) throws Exception {          logger.info( "open index: " + key);          File file= new File(baseIndexDir,key);          if (!file.exists()){              throw new NoSuchElementException(key + " index doesn't exist!" );          }          FSDirectory dir =FSDirectory.open(file);          return  IndexReader.open(dir, true );      }        @Override      public void destroyObject(String key, IndexReader reader) throws Exception {          logger.info( "destroy index: " + key);          reader.close();      }        @Override      public boolean validateObject(String key, IndexReader reader) {          logger.info( "validate index: " + key);          if (reader!= null ){              return true ;          }          return false ;      }        @Override      public void activateObject(String key, IndexReader reader) throws Exception {          logger.debug( "activate index: " + key);      }        @Override      public void passivateObject(String key, IndexReader reader) throws Exception {          logger.debug( "passivate index: " + key);      } }

• Usage

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  import org.apache.commons.pool.KeyedObjectPool; import org.apache.commons.pool.impl.GenericKeyedObjectPool; import org.apache.commons.pool.impl.GenericKeyedObjectPoolFactory; import org.apache.lucene.document.Document; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.Term; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.NGramPhraseQuery; import org.apache.lucene.search.ScoreDoc; import org.apache.lucene.search.TopDocs;     public class LuceneSearcherPool {        public static void main(String[] args) {          GenericKeyedObjectPool.Config config = new GenericKeyedObjectPool.Config();          GenericKeyedObjectPoolFactory<String, IndexReader> poolFactory = new GenericKeyedObjectPoolFactory<String, IndexReader>( new IndexReaderFactory( "/var/data/ostree/index" ), config);          KeyedObjectPool<String, IndexReader> pool = poolFactory.createPool();          try {              String[] dates = { "2012-01-01" , "2011-01-04" , "2012-01-05" };              for (String date : dates) {                  for ( int i = 0 ; i < 10 ; i++) {                      long start = System.currentTimeMillis();                      IndexReader reader = pool.borrowObject(date);                      test(reader);                      pool.returnObject(date, reader);                      System.out.println(date + ":" + i + ";" + (System.currentTimeMillis() - start));                  }              }              pool.close();          } catch (Exception ex) {            }      }        public static void test(IndexReader reader) throws Exception {            String input = "java" ;          int num = 5 ;            IndexSearcher searcher = new IndexSearcher(reader);            //build your query here         //Query query =          TopDocs hits = searcher.search(query, num);          for (ScoreDoc scoreDoc : hits.scoreDocs) {              Document doc = searcher.doc(scoreDoc.doc);            // handle the Document          }          searcher.close();      } }