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Lucene example source code file (NoMergePolicy.java)

This example Lucene source code file (NoMergePolicy.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

compound_files, corruptindexexception, corruptindexexception, io, ioexception, map, mergepolicy, mergespecification, mergespecification, no_compound_files, nomergepolicy, nomergepolicy, override, override, string, util

The Lucene NoMergePolicy.java source code

package org.apache.lucene.index;

/**
 * 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.
 */

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

/**
 * A {@link MergePolicy} which never returns merges to execute (hence it's
 * name). It is also a singleton and can be accessed through
 * {@link NoMergePolicy#NO_COMPOUND_FILES} if you want to indicate the index
 * does not use compound files, or through {@link NoMergePolicy#COMPOUND_FILES}
 * otherwise. Use it if you want to prevent an {@link IndexWriter} from ever
 * executing merges, without going through the hassle of tweaking a merge
 * policy's settings to achieve that, such as changing its merge factor.
 */
public final class NoMergePolicy extends MergePolicy {

  /**
   * A singleton {@link NoMergePolicy} which indicates the index does not use
   * compound files.
   */
  public static final MergePolicy NO_COMPOUND_FILES = new NoMergePolicy(false);

  /**
   * A singleton {@link NoMergePolicy} which indicates the index uses compound
   * files.
   */
  public static final MergePolicy COMPOUND_FILES = new NoMergePolicy(true);

  private final boolean useCompoundFile;
  
  private NoMergePolicy(boolean useCompoundFile) {
    // prevent instantiation
    this.useCompoundFile = useCompoundFile;
  }

  @Override
  public void close() {}

  @Override
  public MergeSpecification findMerges(SegmentInfos segmentInfos)
      throws CorruptIndexException, IOException { return null; }

  @Override
  public MergeSpecification findMergesForOptimize(SegmentInfos segmentInfos,
             int maxSegmentCount, Map<SegmentInfo,Boolean> segmentsToOptimize)
      throws CorruptIndexException, IOException { return null; }

  @Override
  public MergeSpecification findMergesToExpungeDeletes(SegmentInfos segmentInfos)
      throws CorruptIndexException, IOException { return null; }

  @Override
  public boolean useCompoundFile(SegmentInfos segments, SegmentInfo newSegment) { return useCompoundFile; }

  @Override
  public void setIndexWriter(IndexWriter writer) {}

  @Override
  public String toString() {
    return "NoMergePolicy";
  }
}

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



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