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/*
* 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.repositories;
import org.elasticsearch.common.UUIDs;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshots;
import org.elasticsearch.snapshots.SnapshotsService;
import org.elasticsearch.xcontent.ToXContentFragment;
import org.elasticsearch.xcontent.XContentBuilder;
import org.elasticsearch.xcontent.XContentParser;
import java.io.IOException;
import java.util.Objects;
import java.util.Random;
/**
* The generation ID of a shard, used to name the shard-level {@code index-$SHARD_GEN} file that represents a {@link
* BlobStoreIndexShardSnapshots} instance. Before 7.6 ({@link SnapshotsService#SHARD_GEN_IN_REPO_DATA_VERSION}) these generations were
* numeric, but recent versions use a UUID instead.
*/
public final class ShardGeneration implements Writeable, ToXContentFragment {
private final String rawGeneration;
/**
* @return a new (fresh) shard generation.
*/
public static ShardGeneration newGeneration() {
return new ShardGeneration(UUIDs.randomBase64UUID());
}
/**
* @return a new (fresh) shard generation generated using the given {@link Random} for repeatability in tests.
*/
public static ShardGeneration newGeneration(Random random) {
return new ShardGeneration(UUIDs.randomBase64UUID(random));
}
/**
* Construct a specific {@link ShardGeneration}. Doing this is generally a mistake, you should either create a new fresh one with {@link
* #newGeneration} or else read one from the wire with {@link #ShardGeneration(StreamInput)} or {@link #fromXContent(XContentParser)}.
*/
public ShardGeneration(String rawGeneration) {
this.rawGeneration = Objects.requireNonNull(rawGeneration);
}
/**
* Construct a specific {@link ShardGeneration} for a repository using the legacy numeric format.
*/
public ShardGeneration(long legacyGeneration) {
rawGeneration = String.valueOf(legacyGeneration);
}
public ShardGeneration(StreamInput in) throws IOException {
rawGeneration = in.readString();
}
public static ShardGeneration fromXContent(XContentParser parser) throws IOException {
final String generationString = parser.textOrNull();
// it's null iff using legacy generations that aren't tracked in the RepositoryData
return generationString == null ? null : new ShardGeneration(generationString);
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeString(rawGeneration);
}
/**
* Convert to a {@link String} for use in naming the {@code index-$SHARD_GEN} blob containing a {@link BlobStoreIndexShardSnapshots}.
*/
public String toBlobNamePart() {
return rawGeneration;
}
@Override
public String toString() {
return rawGeneration;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ShardGeneration that = (ShardGeneration) o;
return rawGeneration.equals(that.rawGeneration);
}
@Override
public int hashCode() {
return Objects.hash(rawGeneration);
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.value(rawGeneration);
return builder;
}
}