Lucene example source code file (IndexMergeTool.java)

This example Lucene source code file (IndexMergeTool.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

directory, directory, file, file, fsdirectory, indexmergetool, indexwriter, indexwriter, indexwriterconfig, io, ioexception, ioexception

The Lucene IndexMergeTool.java source code

package org.apache.lucene.misc;

/**
  * Copyright 2005 The Apache Software Foundation
  *
  * Licensed 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.
  */

import org.apache.lucene.analysis.WhitespaceAnalyzer;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

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

/**
 * Merges indices specified on the command line into the index
 * specified as the first command line argument.
 */
public class IndexMergeTool {
  public static void main(String[] args) throws IOException {
    if (args.length < 3) {
      System.err.println("Usage: IndexMergeTool <mergedIndex>   [index3] ...");
      System.exit(1);
    }
    FSDirectory mergedIndex = FSDirectory.open(new File(args[0]));

    IndexWriter writer = new IndexWriter(mergedIndex, new IndexWriterConfig(
        Version.LUCENE_CURRENT, new WhitespaceAnalyzer(Version.LUCENE_CURRENT))
        .setOpenMode(OpenMode.CREATE));

    Directory[] indexes = new Directory[args.length - 1];
    for (int i = 1; i < args.length; i++) {
      indexes[i  - 1] = FSDirectory.open(new File(args[i]));
    }

    System.out.println("Merging...");
    writer.addIndexes(indexes);

    System.out.println("Optimizing...");
    writer.optimize();
    writer.close();
    System.out.println("Done.");
  }
}