| /* |
| * 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.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.streaming.runtime.streamrecord.StreamRecord; |
| |
| /** |
| * A {@link StreamOperator} for executing a {@link ReduceFunction} on a {@link |
| * org.apache.flink.streaming.api.datastream.KeyedStream}. |
| */ |
| @Internal |
| public class StreamGroupedReduceOperator<IN> |
| extends AbstractUdfStreamOperator<IN, ReduceFunction<IN>> |
| implements OneInputStreamOperator<IN, IN> { |
| |
| private static final long serialVersionUID = 1L; |
| |
| private static final String STATE_NAME = "_op_state"; |
| |
| private transient ValueState<IN> values; |
| |
| private final TypeSerializer<IN> serializer; |
| |
| public StreamGroupedReduceOperator(ReduceFunction<IN> reducer, TypeSerializer<IN> serializer) { |
| super(reducer); |
| this.serializer = serializer; |
| } |
| |
| @Override |
| public void open() throws Exception { |
| super.open(); |
| ValueStateDescriptor<IN> stateId = new ValueStateDescriptor<>(STATE_NAME, serializer); |
| values = getPartitionedState(stateId); |
| } |
| |
| @Override |
| public void processElement(StreamRecord<IN> element) throws Exception { |
| IN value = element.getValue(); |
| IN currentValue = values.value(); |
| |
| if (currentValue != null) { |
| IN reduced = userFunction.reduce(currentValue, value); |
| values.update(reduced); |
| output.collect(element.replace(reduced)); |
| } else { |
| values.update(value); |
| output.collect(element.replace(value)); |
| } |
| } |
| } |