org.olat.search.service.indexer.IndexWriterHolder.java Source code

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Here is the source code for org.olat.search.service.indexer.IndexWriterHolder.java

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/**
 * <a href="http://www.openolat.org">
 * OpenOLAT - Online Learning and Training</a><br>
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); <br>
 * you may not use this file except in compliance with the License.<br>
 * You may obtain a copy of the License at the
 * <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache homepage</a>
 * <p>
 * Unless required by applicable law or agreed to in writing,<br>
 * software distributed under the License is distributed on an "AS IS" BASIS, <br>
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
 * See the License for the specific language governing permissions and <br>
 * limitations under the License.
 * <p>
 * Initial code contributed and copyrighted by<br>
 * frentix GmbH, http://www.frentix.com
 * <p>
 */
package org.olat.search.service.indexer;

import java.io.IOException;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.Directory;
import org.olat.core.logging.OLog;
import org.olat.core.logging.Tracing;
import org.olat.core.util.CodeHelper;

/**
 * 
 * Initial date: 05.03.2013<br>
 * @author srosse, stephane.rosse@frentix.com, http://www.frentix.com
 *
 */
public class IndexWriterHolder {
    private static final OLog log = Tracing.createLoggerFor(IndexWriterHolder.class);

    private Directory indexPath;
    private JmsIndexer indexer;

    private AtomicInteger counter = new AtomicInteger(0);
    private IndexWriter writerRef;

    public IndexWriterHolder(Directory indexPath, JmsIndexer indexer) throws IOException {
        this.indexPath = indexPath;
        this.indexer = indexer;
    }

    /**
     * @return true if it has created the index
     */
    public synchronized boolean ensureIndexExists() {
        boolean created = false;
        IndexWriter writer = null;
        try {
            if (!DirectoryReader.indexExists(indexPath)) {
                writer = getAndLock();
                created = true;
            }
        } catch (IOException e) {
            log.error("", e);
        } finally {
            release(writer);
        }
        return created;
    }

    public synchronized IndexWriter getAndLock() throws IOException {
        if (writerRef == null) {
            long start = System.nanoTime();
            IndexWriter indexWriter = new IndexWriter(indexPath, indexer.newIndexWriterConfig());
            if (!DirectoryReader.indexExists(indexPath)) {
                indexWriter.commit();//make sure it exists
            }
            log.info("Opening writer takes (ms): " + CodeHelper.nanoToMilliTime(start));
            writerRef = indexWriter;
        }
        counter.incrementAndGet();
        return writerRef;
    }

    public synchronized void release(IndexWriter indexWriter) {
        if (indexWriter != null) {
            try {
                int used = counter.decrementAndGet();
                if (used == 0) {
                    long start = System.nanoTime();
                    indexWriter.commit();
                    indexWriter.close();
                    writerRef = null;
                    log.info("Close writer takes (ms): " + CodeHelper.nanoToMilliTime(start));
                }
            } catch (Exception e) {
                log.error("", e);
            }
        }
    }

    public synchronized void close() {
        IndexWriter indexWriter = writerRef;
        if (indexWriter != null) {
            try {
                indexWriter.commit();
                indexWriter.close();
            } catch (IOException e) {
                log.error("", e);
            }
        }
    }
}