org.apache.jena.larq.IndexBuilderBase.java Source code

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Here is the source code for org.apache.jena.larq.IndexBuilderBase.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.larq;

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

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.RAMDirectory;

/** Root class for index creation. */

public class IndexBuilderBase implements IndexBuilder {
    private Directory dir = null;
    private boolean avoid_duplicates = true;

    // Use this for incremental indexing?
    //private IndexModifier modifier ;

    private IndexWriter indexWriter = null;
    //private IndexReader indexReader = null ;

    //private boolean isClosed ;

    /** Create an in-memory index */

    public IndexBuilderBase() {
        dir = new RAMDirectory();
        makeIndex();
    }

    /** Manage a Lucene index that has already been created */

    public IndexBuilderBase(IndexWriter existingWriter) {
        dir = existingWriter.getDirectory();
        indexWriter = existingWriter;
    }

    /** Create an on-disk index */

    public IndexBuilderBase(File fileDir) {
        try {
            dir = FSDirectory.open(fileDir);
            makeIndex();
        } catch (Exception ex) {
            throw new ARQLuceneException("IndexBuilderLARQ", ex);
        }

    }

    /** Create an on-disk index */

    public IndexBuilderBase(String fileDir) {
        try {
            dir = FSDirectory.open(new File(fileDir));
            makeIndex();
        } catch (Exception ex) {
            throw new ARQLuceneException("IndexBuilderLARQ", ex);
        }
    }

    private void makeIndex() {
        try {
            indexWriter = IndexWriterFactory.create(dir);
        } catch (Exception ex) {
            throw new ARQLuceneException("IndexBuilderLARQ", ex);
        }
    }

    public boolean avoidDuplicates() {
        return avoid_duplicates;
    }

    public void setAvoidDuplicates(boolean avoidDuplicates) {
        avoid_duplicates = avoidDuplicates;
    }

    protected IndexWriter getIndexWriter() {
        return indexWriter;
    }

    protected IndexReader getIndexReader() {
        try {
            flushWriter();
            if (indexWriter != null) {
                return IndexReader.open(indexWriter, true); // Let's use the Near Real Time (NRT) 
            } else {
                return IndexReader.open(dir);
            }
        } catch (Exception e) {
            throw new ARQLuceneException("getIndexReader", e);
        }
    }

    /** Close the writing index permanently.  Optimizes the index. */

    @Override
    public void closeWriter() {
        closeWriter(true);
    }

    /** Close the writing index permanently.
     * @param optimize  Run Lucene optimize on the index before closing.
     */

    public void closeWriter(boolean optimize) {
        if (optimize)
            flushWriter();
        try {
            if (indexWriter != null)
                indexWriter.close();
        } catch (IOException ex) {
            throw new ARQLuceneException("closeIndex", ex);
        }
        indexWriter = null;
    }

    @Override
    @SuppressWarnings("deprecation")
    public void flushWriter() {
        try {
            if (indexWriter != null)
                indexWriter.optimize();
        } catch (IOException ex) {
            throw new ARQLuceneException("flushWriter", ex);
        }
    }

    /** Get a search index used by LARQ */

    @Override
    public IndexLARQ getIndex() {
        //ARQ 2.2 : no longer close the index.  closeForWriting() ;
        return new IndexLARQ(getIndexReader());
    }

}