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.Set;
/**
* 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, Set<SegmentInfo> segmentsToOptimize)
throws CorruptIndexException, IOException { return null; }
@Override
public MergeSpecification findMergesToExpungeDeletes(SegmentInfos segmentInfos)
throws CorruptIndexException, IOException { return null; }
@Override
public boolean useCompoundDocStore(SegmentInfos segments) { return useCompoundFile; }
@Override
public boolean useCompoundFile(SegmentInfos segments, SegmentInfo newSegment) { return useCompoundFile; }
@Override
public void setIndexWriter(IndexWriter writer) {}
@Override
public String toString() {
return "NoMergePolicy";
}
}