org.elasticsearch.index.shard.ShardUtils Maven / Gradle / Ivy
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* 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.index.shard;
import org.apache.lucene.index.AtomicReader;
import org.apache.lucene.index.SegmentReader;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.lucene.SegmentReaderUtils;
import org.elasticsearch.index.store.DirectoryUtils;
import org.elasticsearch.index.store.Store;
/**
*/
public class ShardUtils {
/**
* Tries to extract the shard id from a reader if possible, when its not possible,
* will return null. This method requires the reader to be a {@link SegmentReader}
* and the directory backing it to be {@link org.elasticsearch.index.store.Store.StoreDirectory}.
* This will be the case in almost all cases, except for percolator currently.
*/
@Nullable
public static ShardId extractShardId(AtomicReader reader) {
return extractShardId(SegmentReaderUtils.segmentReaderOrNull(reader));
}
@Nullable
private static ShardId extractShardId(SegmentReader reader) {
if (reader != null) {
assert reader.getRefCount() > 0 : "SegmentReader is already closed";
// reader.directory doesn't call ensureOpen for internal reasons.
Store.StoreDirectory storeDir = DirectoryUtils.getStoreDirectory(reader.directory());
if (storeDir != null) {
return storeDir.shardId();
}
}
return null;
}
}