content: package org.apache.lucene.index;
  
  import java.io.IOException;
  
  /**
   * 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.
   */
  
  /** This is a {@link LogMergePolicy} that measures size of a
   *  segment as the number of documents (not taking deletions
   *  into account). */
  
  public class LogDocMergePolicy extends LogMergePolicy {
  
    /** Default minimum segment size.  @see setMinMergeDocs */
    public static final int DEFAULT_MIN_MERGE_DOCS = 1000;
  
    public LogDocMergePolicy() {
      minMergeSize = DEFAULT_MIN_MERGE_DOCS;
      
      // maxMergeSize(ForForcedMerge) are never used by LogDocMergePolicy; set
      // it to Long.MAX_VALUE to disable it
      maxMergeSize = Long.MAX_VALUE;
      maxMergeSizeForForcedMerge = Long.MAX_VALUE;
    }
  
    @Override
    protected long size(SegmentInfo info) throws IOException {
      return sizeDocs(info);
    }
  
    /** Sets the minimum size for the lowest level segments.
     * Any segments below this size are considered to be on
     * the same level (even if they vary drastically in size)
     * and will be merged whenever there are mergeFactor of
     * them.  This effectively truncates the "long tail" of
     * small segments that would otherwise be created into a
     * single level.  If you set this too large, it could
     * greatly increase the merging cost during indexing (if
     * you flush many small segments). */
    public void setMinMergeDocs(int minMergeDocs) {
      minMergeSize = minMergeDocs;
    }
  
    /** Get the minimum size for a segment to remain
     *  un-merged.
     *  @see #setMinMergeDocs **/
    public int getMinMergeDocs() {
      return (int) minMergeSize;
    }
  }
  