org.apache.flink.runtime.state.heap.StateMapSnapshot Maven / Gradle / Ivy
/*
* 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.heap;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.core.memory.DataOutputView;
import org.apache.flink.runtime.state.StateSnapshotTransformer;
import org.apache.flink.util.Preconditions;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.IOException;
/**
* Base class for snapshots of a {@link StateMap}.
*
* @param type of key
* @param type of namespace
* @param type of state
*/
public abstract class StateMapSnapshot> {
/**
* The {@link StateMap} from which this snapshot was created.
*/
protected final T owningStateMap;
public StateMapSnapshot(T stateMap) {
this.owningStateMap = Preconditions.checkNotNull(stateMap);
}
/**
* Returns true iff the given state map is the owner of this snapshot object.
*/
public boolean isOwner(T stateMap) {
return owningStateMap == stateMap;
}
/**
* Release the snapshot.
*/
public void release() {
}
/**
* Writes the state in this snapshot to output. The state need to be transformed
* with the given transformer if the transformer is non-null.
*
* @param keySerializer the key serializer.
* @param namespaceSerializer the namespace serializer.
* @param stateSerializer the state serializer.
* @param dov the output.
* @param stateSnapshotTransformer state transformer, and can be null.
* @throws IOException on write-related problems.
*/
public abstract void writeState(
TypeSerializer keySerializer,
TypeSerializer namespaceSerializer,
TypeSerializer stateSerializer,
@Nonnull DataOutputView dov,
@Nullable StateSnapshotTransformer stateSnapshotTransformer) throws IOException;
}