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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.index.translog;
import org.apache.lucene.store.AlreadyClosedException;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.common.lease.Releasables;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* A snapshot composed out of multiple snapshots
*/
final class MultiSnapshot implements Translog.Snapshot {
private final Translog.Snapshot[] translogs;
private AtomicBoolean closed = new AtomicBoolean(false);
private final int estimatedTotalOperations;
private int index;
/**
* Creates a new point in time snapshot of the given snapshots. Those snapshots are always iterated in-order.
*/
MultiSnapshot(Translog.Snapshot[] translogs) {
this.translogs = translogs;
int ops = 0;
for (Translog.Snapshot translog : translogs) {
final int tops = translog.estimatedTotalOperations();
if (tops == TranslogReader.UNKNOWN_OP_COUNT) {
ops = TranslogReader.UNKNOWN_OP_COUNT;
break;
}
assert tops >= 0 : "tops must be positive but was: " + tops;
ops += tops;
}
estimatedTotalOperations = ops;
index = 0;
}
@Override
public int estimatedTotalOperations() {
return estimatedTotalOperations;
}
@Override
public Translog.Operation next() throws IOException {
ensureOpen();
for (; index < translogs.length; index++) {
final Translog.Snapshot current = translogs[index];
Translog.Operation op = current.next();
if (op != null) { // if we are null we move to the next snapshot
return op;
}
}
return null;
}
protected void ensureOpen() {
if (closed.get()) {
throw new AlreadyClosedException("snapshot already closed");
}
}
@Override
public void close() throws ElasticsearchException {
if (closed.compareAndSet(false, true)) {
Releasables.close(translogs);
}
}
}