org.elasticsearch.common.lucene.index.SequentialStoredFieldsLeafReader Maven / Gradle / Ivy
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Elasticsearch subproject :server
/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.common.lucene.index;
import org.apache.lucene.codecs.StoredFieldsReader;
import org.apache.lucene.index.CodecReader;
import org.apache.lucene.index.FilterLeafReader;
import org.apache.lucene.index.LeafReader;
import java.io.IOException;
/**
* A {@link FilterLeafReader} that exposes a {@link StoredFieldsReader}
* optimized for sequential access. This class should be used by custom
* {@link FilterLeafReader} that are used at search time in order to
* leverage sequential access when retrieving stored fields in queries,
* aggregations or during the fetch phase.
*/
public abstract class SequentialStoredFieldsLeafReader extends FilterLeafReader {
/**
* Construct a StoredFieldsFilterLeafReader based on the specified base reader.
*
Note that base reader is closed if this FilterLeafReader is closed.
*
* @param in specified base reader.
*/
public SequentialStoredFieldsLeafReader(LeafReader in) {
super(in);
}
/**
* Implementations should return a {@link StoredFieldsReader} that wraps the provided reader
* that is optimized for sequential access (adjacent doc ids).
*/
protected abstract StoredFieldsReader doGetSequentialStoredFieldsReader(StoredFieldsReader reader);
/**
* Returns a {@link StoredFieldsReader} optimized for sequential access (adjacent doc ids).
*/
public StoredFieldsReader getSequentialStoredFieldsReader() throws IOException {
if (in instanceof CodecReader) {
CodecReader reader = (CodecReader) in;
return doGetSequentialStoredFieldsReader(reader.getFieldsReader().getMergeInstance());
} else if (in instanceof SequentialStoredFieldsLeafReader) {
SequentialStoredFieldsLeafReader reader = (SequentialStoredFieldsLeafReader) in;
return doGetSequentialStoredFieldsReader(reader.getSequentialStoredFieldsReader());
} else {
throw new IOException("requires a CodecReader or a SequentialStoredFieldsLeafReader, got " + in.getClass());
}
}
}