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Lucene example source code file (OpenReaderTask.java)

This example Lucene source code file (OpenReaderTask.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

collection, config, indexcommit, indexreader, io, ioexception, ioexception, openreadertask, openreadertask, override, override, perftask, string, string, user_data, util

The Lucene OpenReaderTask.java source code

package org.apache.lucene.benchmark.byTask.tasks;

 * 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,
 * See the License for the specific language governing permissions and
 * limitations under the License.

import java.io.IOException;
import java.util.Collection;
import java.util.Map;

import org.apache.lucene.benchmark.byTask.PerfRunData;
import org.apache.lucene.benchmark.byTask.utils.Config;
import org.apache.lucene.index.IndexCommit;
import org.apache.lucene.index.IndexDeletionPolicy;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.store.Directory;

 * Open an index reader.
 * <br>Other side effects: index reader object in perfRunData is set.
 * <br> Optional params readOnly,commitUserData eg. OpenReader(false,commit1)
public class OpenReaderTask extends PerfTask {
  public static final String USER_DATA = "userData";
  private boolean readOnly = true;
  private String commitUserData = null;

  public OpenReaderTask(PerfRunData runData) {

  public int doLogic() throws IOException {
    Directory dir = getRunData().getDirectory();
    Config config = getRunData().getConfig();
    IndexReader r = null;
    final IndexDeletionPolicy deletionPolicy;
    if (readOnly) {
      deletionPolicy = null;
    } else {
      deletionPolicy = CreateIndexTask.getIndexDeletionPolicy(config);
    if (commitUserData != null) {
      r = IndexReader.open(OpenReaderTask.findIndexCommit(dir, commitUserData),
    } else {
      r = IndexReader.open(dir,
    // We transfer reference to the run data
    return 1;
  public void setParams(String params) {
    if (params != null) {
      String[] split = params.split(",");
      if (split.length > 0) {
        readOnly = Boolean.valueOf(split[0]).booleanValue();
      if (split.length > 1) {
        commitUserData = split[1];

  public boolean supportsParams() {
    return true;

  public static IndexCommit findIndexCommit(Directory dir, String userData) throws IOException {
    Collection<IndexCommit> commits = IndexReader.listCommits(dir);
    for (final IndexCommit ic : commits) {
      Map<String,String> map = ic.getUserData();
      String ud = null;
      if (map != null) {
        ud = map.get(USER_DATA);
      if (ud != null && ud.equals(userData)) {
        return ic;

    throw new IOException("index does not contain commit with userData: " + userData);

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene OpenReaderTask.java source code file:

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