org.apache.flink.streaming.api.operators.sorted.state.BatchExecutionKeyReducingState Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.streaming.api.operators.sorted.state;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.common.state.ReducingState;
import org.apache.flink.api.common.state.ReducingStateDescriptor;
import org.apache.flink.api.common.state.State;
import org.apache.flink.api.common.state.StateDescriptor;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.state.internal.InternalReducingState;
import java.io.IOException;
/** A {@link ReducingState} which keeps value for a single key at a time. */
class BatchExecutionKeyReducingState
extends MergingAbstractBatchExecutionKeyState
implements InternalReducingState {
private final ReduceFunction reduceFunction;
public BatchExecutionKeyReducingState(
T defaultValue,
ReduceFunction reduceFunction,
TypeSerializer keySerializer,
TypeSerializer namespaceSerializer,
TypeSerializer stateSerializer) {
super(defaultValue, keySerializer, namespaceSerializer, stateSerializer);
this.reduceFunction = reduceFunction;
}
@Override
public T get() {
return getOrDefault();
}
@Override
public void add(T value) throws IOException {
if (value == null) {
clear();
return;
}
try {
T currentNamespaceValue = getCurrentNamespaceValue();
if (currentNamespaceValue != null) {
setCurrentNamespaceValue(reduceFunction.reduce(currentNamespaceValue, value));
} else {
setCurrentNamespaceValue(value);
}
} catch (Exception e) {
throw new IOException("Exception while applying ReduceFunction in reducing state", e);
}
}
@SuppressWarnings("unchecked")
static IS create(
TypeSerializer keySerializer,
TypeSerializer namespaceSerializer,
StateDescriptor stateDesc) {
return (IS)
new BatchExecutionKeyReducingState<>(
stateDesc.getDefaultValue(),
((ReducingStateDescriptor) stateDesc).getReduceFunction(),
keySerializer,
namespaceSerializer,
stateDesc.getSerializer());
}
@Override
protected T merge(T target, T source) throws Exception {
return reduceFunction.reduce(target, source);
}
}