org.elasticsearch.index.shard.ShardUtils Maven / Gradle / Ivy
/*
* Licensed to ElasticSearch and Shay Banon 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.index.shard;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.SegmentReader;
import org.elasticsearch.common.Nullable;
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(IndexReader reader) {
if (reader instanceof SegmentReader) {
SegmentReader sReader = (SegmentReader) reader;
if (sReader.directory() instanceof Store.StoreDirectory) {
return ((Store.StoreDirectory) sReader.directory()).shardId();
}
}
return null;
}
}