org.neo4j.index.impl.lucene.legacy.WritableIndexReferenceFactory.java Source code

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Here is the source code for org.neo4j.index.impl.lucene.legacy.WritableIndexReferenceFactory.java

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/*
 * Copyright (c) 2002-2016 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.index.impl.lucene.legacy;

import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.similarities.Similarity;
import org.apache.lucene.store.Directory;

import java.io.File;
import java.io.IOException;

class WritableIndexReferenceFactory extends IndexReferenceFactory {
    WritableIndexReferenceFactory(LuceneDataSource.LuceneFilesystemFacade filesystemFacade, File baseStorePath,
            IndexTypeCache typeCache) {
        super(filesystemFacade, baseStorePath, typeCache);
    }

    @Override
    IndexReference createIndexReference(IndexIdentifier identifier) throws IOException {
        IndexWriter writer = newIndexWriter(identifier);
        IndexReader reader = DirectoryReader.open(writer, true);
        IndexSearcher indexSearcher = newIndexSearcher(identifier, reader);
        return new WritableIndexReference(identifier, indexSearcher, writer);
    }

    /**
     * If nothing has changed underneath (since the searcher was last created
     * or refreshed) {@code searcher} is returned. But if something has changed a
     * refreshed searcher is returned. It makes use if the
     * {@link DirectoryReader#openIfChanged(DirectoryReader, IndexWriter, boolean)} which faster than opening an index
     * from
     * scratch.
     *
     * @param indexReference the {@link IndexReference} to refresh.
     * @return a refreshed version of the searcher or, if nothing has changed,
     *         {@code null}.
     * @throws RuntimeException if there's a problem with the index.
     */
    @Override
    IndexReference refresh(IndexReference indexReference) {
        try {
            DirectoryReader reader = (DirectoryReader) indexReference.getSearcher().getIndexReader();
            IndexWriter writer = indexReference.getWriter();
            IndexReader reopened = DirectoryReader.openIfChanged(reader, writer);
            if (reopened != null) {
                IndexSearcher newSearcher = newIndexSearcher(indexReference.getIdentifier(), reopened);
                indexReference.detachOrClose();
                return new WritableIndexReference(indexReference.getIdentifier(), newSearcher, writer);
            }
            return indexReference;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private IndexWriter newIndexWriter(IndexIdentifier identifier) {
        try {
            Directory indexDirectory = getIndexDirectory(identifier);
            IndexType type = getType(identifier);
            IndexWriterConfig writerConfig = new IndexWriterConfig(type.analyzer);
            writerConfig.setIndexDeletionPolicy(new MultipleBackupDeletionPolicy());
            Similarity similarity = type.getSimilarity();
            if (similarity != null) {
                writerConfig.setSimilarity(similarity);
            }
            return new IndexWriter(indexDirectory, writerConfig);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}