org.opensearch.common.lucene.index.SequentialStoredFieldsLeafReader Maven / Gradle / Ivy
/*
* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*/
package org.opensearch.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());
}
}
}