org.apache.lucene.codecs.compressing.CompressingTermVectorsFormat Maven / Gradle / Ivy
/*
* COPIED FROM APACHE LUCENE 4.7.2
*
* Git URL: [email protected]:apache/lucene.git, tag: releases/lucene-solr/4.7.2, path: lucene/core/src/java
*
* (see https://issues.apache.org/jira/browse/OAK-10786 for details)
*/
package org.apache.lucene.codecs.compressing;
/*
* 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 org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.codecs.StoredFieldsFormat;
import org.apache.lucene.codecs.TermVectorsFormat;
import org.apache.lucene.codecs.TermVectorsReader;
import org.apache.lucene.codecs.TermVectorsWriter;
import org.apache.lucene.index.FieldInfos;
import org.apache.lucene.index.SegmentInfo;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IOContext;
/**
* A {@link TermVectorsFormat} that compresses chunks of documents together in
* order to improve the compression ratio.
* @lucene.experimental
*/
public class CompressingTermVectorsFormat extends TermVectorsFormat {
private final String formatName;
private final String segmentSuffix;
private final CompressionMode compressionMode;
private final int chunkSize;
/**
* Create a new {@link CompressingTermVectorsFormat}.
*
* formatName is the name of the format. This name will be used
* in the file formats to perform
* {@link CodecUtil#checkHeader(org.apache.lucene.store.DataInput, String, int, int) codec header checks}.
*
* The compressionMode parameter allows you to choose between
* compression algorithms that have various compression and decompression
* speeds so that you can pick the one that best fits your indexing and
* searching throughput. You should never instantiate two
* {@link CompressingTermVectorsFormat}s that have the same name but
* different {@link CompressionMode}s.
*
* chunkSize is the minimum byte size of a chunk of documents.
* Higher values of chunkSize should improve the compression
* ratio but will require more memory at indexing time and might make document
* loading a little slower (depending on the size of your OS cache compared
* to the size of your index).
*
* @param formatName the name of the {@link StoredFieldsFormat}
* @param segmentSuffix a suffix to append to files created by this format
* @param compressionMode the {@link CompressionMode} to use
* @param chunkSize the minimum number of bytes of a single chunk of stored documents
* @see CompressionMode
*/
public CompressingTermVectorsFormat(String formatName, String segmentSuffix,
CompressionMode compressionMode, int chunkSize) {
this.formatName = formatName;
this.segmentSuffix = segmentSuffix;
this.compressionMode = compressionMode;
if (chunkSize < 1) {
throw new IllegalArgumentException("chunkSize must be >= 1");
}
this.chunkSize = chunkSize;
}
@Override
public final TermVectorsReader vectorsReader(Directory directory,
SegmentInfo segmentInfo, FieldInfos fieldInfos, IOContext context)
throws IOException {
return new CompressingTermVectorsReader(directory, segmentInfo, segmentSuffix,
fieldInfos, context, formatName, compressionMode);
}
@Override
public final TermVectorsWriter vectorsWriter(Directory directory,
SegmentInfo segmentInfo, IOContext context) throws IOException {
return new CompressingTermVectorsWriter(directory, segmentInfo, segmentSuffix,
context, formatName, compressionMode, chunkSize);
}
@Override
public String toString() {
return getClass().getSimpleName() + "(compressionMode=" + compressionMode
+ ", chunkSize=" + chunkSize + ")";
}
}