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Lucene example source code file (UpgradeIndexMergePolicy.java)
The Lucene UpgradeIndexMergePolicy.java source codepackage 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 org.apache.lucene.util.Constants; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.HashMap; /** This {@link MergePolicy} is used for upgrading all existing segments of * an index when calling {@link IndexWriter#optimize()}. * All other methods delegate to the base {@code MergePolicy} given to the constructor. * This allows for an as-cheap-as possible upgrade of an older index by only upgrading segments that * are created by previous Lucene versions. Optimize does no longer really optimize * it is just used to "optimize" older segment versions away. * <p>In general one would use {@link IndexUpgrader}, but for a fully customizeable upgrade, * you can use this like any other {@code MergePolicy} and call {@link IndexWriter#optimize()}: * <pre class="prettyprint lang-java"> * IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_XX, new KeywordAnalyzer()); * iwc.setMergePolicy(new UpgradeIndexMergePolicy(iwc.getMergePolicy())); * IndexWriter w = new IndexWriter(dir, iwc); * w.optimize(); * w.close(); * </pre> * <p>Warning: This merge policy may reorder documents if the index was partially * upgraded before calling optimize (e.g., documents were added). If your application relies * on "monotonicity" of doc IDs (which means that the order in which the documents * were added to the index is preserved), do a full optimize instead. Please note, the * delegate {@code MergePolicy} may also reorder documents. * @lucene.experimental * @see IndexUpgrader */ public class UpgradeIndexMergePolicy extends MergePolicy { protected final MergePolicy base; /** Wrap the given {@link MergePolicy} and intercept optimize requests to * only upgrade segments written with previous Lucene versions. */ public UpgradeIndexMergePolicy(MergePolicy base) { this.base = base; } /** Returns if the given segment should be upgraded. The default implementation * will return {@code !Constants.LUCENE_MAIN_VERSION.equals(si.getVersion())}, * so all segments created with a different version number than this Lucene version will * get upgraded. */ protected boolean shouldUpgradeSegment(SegmentInfo si) { return !Constants.LUCENE_MAIN_VERSION.equals(si.getVersion()); } @Override public void setIndexWriter(IndexWriter writer) { super.setIndexWriter(writer); base.setIndexWriter(writer); } @Override public MergeSpecification findMerges(SegmentInfos segmentInfos) throws CorruptIndexException, IOException { return base.findMerges(segmentInfos); } @Override public MergeSpecification findMergesForOptimize(SegmentInfos segmentInfos, int maxSegmentCount, Map<SegmentInfo,Boolean> segmentsToOptimize) throws CorruptIndexException, IOException { // first find all old segments final Map<SegmentInfo,Boolean> oldSegments = new HashMap Other Lucene examples (source code examples)Here is a short list of links related to this Lucene UpgradeIndexMergePolicy.java source code file: |
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