org.apache.flink.runtime.state.StateEntry 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;
/**
* Interface of entries in a state backend. Entries are triple of key, namespace, and state.
*
* @param type of key.
* @param type of namespace.
* @param type of state.
*/
public interface StateEntry {
/** Returns the key of this entry. */
K getKey();
/** Returns the namespace of this entry. */
N getNamespace();
/** Returns the state of this entry. */
S getState();
default StateEntry filterOrTransform(StateSnapshotTransformer transformer) {
S newState = transformer.filterOrTransform(getState());
if (newState != null) {
return new SimpleStateEntry<>(getKey(), getNamespace(), newState);
} else {
return null;
}
}
class SimpleStateEntry implements StateEntry {
private final K key;
private final N namespace;
private final S value;
public SimpleStateEntry(K key, N namespace, S value) {
this.key = key;
this.namespace = namespace;
this.value = value;
}
@Override
public K getKey() {
return key;
}
@Override
public N getNamespace() {
return namespace;
}
@Override
public S getState() {
return value;
}
}
}