org.apache.flink.streaming.api.operators.BatchGroupedReduceOperator 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.streaming.api.operators;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.RuntimeExecutionMode;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.common.state.ValueState;
import org.apache.flink.api.common.state.ValueStateDescriptor;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.state.VoidNamespace;
import org.apache.flink.runtime.state.VoidNamespaceSerializer;
import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
/**
* A {@link StreamOperator} for executing a {@link ReduceFunction} on a {@link
* org.apache.flink.streaming.api.datastream.KeyedStream} in a {@link RuntimeExecutionMode#BATCH}
* mode.
*/
@Internal
public class BatchGroupedReduceOperator
extends AbstractUdfStreamOperator>
implements OneInputStreamOperator, Triggerable {
private static final long serialVersionUID = 1L;
private static final String STATE_NAME = "_op_state";
private transient ValueState values;
private final TypeSerializer serializer;
private InternalTimerService timerService;
public BatchGroupedReduceOperator(ReduceFunction reducer, TypeSerializer serializer) {
super(reducer);
this.serializer = serializer;
}
@Override
public void open() throws Exception {
super.open();
ValueStateDescriptor stateId = new ValueStateDescriptor<>(STATE_NAME, serializer);
values = getPartitionedState(stateId);
timerService =
getInternalTimerService("end-key-timers", new VoidNamespaceSerializer(), this);
}
@Override
public void processElement(StreamRecord element) throws Exception {
IN value = element.getValue();
IN currentValue = values.value();
if (currentValue == null) {
// register a timer for emitting the result at the end when this is the
// first input for this key
timerService.registerEventTimeTimer(VoidNamespace.INSTANCE, Long.MAX_VALUE);
} else {
// otherwise, reduce things
value = userFunction.reduce(currentValue, value);
}
values.update(value);
}
@Override
public void onEventTime(InternalTimer timer) throws Exception {
IN currentValue = values.value();
if (currentValue != null) {
output.collect(new StreamRecord<>(currentValue, Long.MAX_VALUE));
}
}
@Override
public void onProcessingTime(InternalTimer timer) throws Exception {}
}