Cache Lucene IndexReader with Apache Commons Pool

IndexReaderFactory.java

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

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();

}