/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.apache.beam.runners.flink.translation.wrappers.streaming.state;
import java.io.DataOutputStream;
/**
* This interface is used to checkpoint key-groups state.
*/
public interface KeyGroupCheckpointedOperator extends KeyGroupRestoringOperator{
/**
* Snapshots the state for a given {@code keyGroupIdx}.
*
* <p>AbstractStreamOperator would call this hook in
* AbstractStreamOperator.snapshotState() while iterating over the key groups.
* @param keyGroupIndex the id of the key-group to be put in the snapshot.
* @param out the stream to write to.
*/
void snapshotKeyGroupState(int keyGroupIndex, DataOutputStream out) throws Exception;
}