org.apache.flink.runtime.state.StateSnapshotRestore Maven / Gradle / Ivy
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* 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.flink.runtime.state;
import org.apache.flink.annotation.Internal;
import javax.annotation.Nonnull;
/**
* Interface to deal with state snapshot and restore of state.
* TODO find better name?
*/
@Internal
public interface StateSnapshotRestore {
/**
* Returns a snapshot of the state.
*/
@Nonnull
StateSnapshot stateSnapshot();
/**
* This method returns a {@link StateSnapshotKeyGroupReader} that can be used to restore the state on a
* per-key-group basis. This method tries to return a reader for the given version hint.
*
* @param readVersionHint the required version of the state to read.
* @return a reader that reads state by key-groups, for the given read version.
*/
@Nonnull
StateSnapshotKeyGroupReader keyGroupReader(int readVersionHint);
}