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/*
* 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.
*/
package org.elasticsearch.common.lucene.index;
import org.apache.lucene.index.FilterLeafReader;
import org.apache.lucene.index.LeafReader;
import org.elasticsearch.index.shard.ShardId;
/**
* A {@link org.apache.lucene.index.FilterLeafReader} that exposes
* Elasticsearch internal per shard / index information like the shard ID.
*/
public final class ElasticsearchLeafReader extends FilterLeafReader {
private final ShardId shardId;
/**
* Construct a FilterLeafReader based on the specified base reader.
*
Note that base reader is closed if this FilterLeafReader is closed.
*
* @param in specified base reader.
*/
public ElasticsearchLeafReader(LeafReader in, ShardId shardId) {
super(in);
this.shardId = shardId;
}
/**
* Returns the shard id this segment belongs to.
*/
public ShardId shardId() {
return this.shardId;
}
@Override
public Object getCoreCacheKey() {
return in.getCoreCacheKey();
}
public static ElasticsearchLeafReader getElasticsearchLeafReader(LeafReader reader) {
if (reader instanceof FilterLeafReader) {
if (reader instanceof ElasticsearchLeafReader) {
return (ElasticsearchLeafReader) reader;
} else {
// We need to use FilterLeafReader#getDelegate and not FilterLeafReader#unwrap, because
// If there are multiple levels of filtered leaf readers then with the unwrap() method it immediately
// returns the most inner leaf reader and thus skipping of over any other filtered leaf reader that
// may be instance of ElasticsearchLeafReader. This can cause us to miss the shardId.
return getElasticsearchLeafReader(((FilterLeafReader) reader).getDelegate());
}
}
return null;
}
}