org.apache.flink.streaming.api.functions.windowing.AggregateApplyWindowFunction 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.streaming.api.functions.windowing;
import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.functions.AggregateFunction;
import org.apache.flink.api.java.operators.translation.WrappingFunction;
import org.apache.flink.streaming.api.windowing.windows.Window;
import org.apache.flink.util.Collector;
import java.util.Collections;
/**
* A {@link WindowFunction} that composes an {@link AggregateFunction} and {@link WindowFunction}.
* Upon invocation, this first applies {@code AggregateFunction} to the input, and then
* finally the {@code WindowFunction} to the single result element.
*
* @param The key type
* @param The window type
* @param The type of the input to the AggregateFunction
* @param The type of the AggregateFunction's accumulator
* @param The type of the AggregateFunction's result, and the input to the WindowFunction
* @param The result type of the WindowFunction
*/
@Internal
public class AggregateApplyWindowFunction
extends WrappingFunction>
implements WindowFunction {
private static final long serialVersionUID = 1L;
private final AggregateFunction aggFunction;
public AggregateApplyWindowFunction(AggregateFunction aggFunction, WindowFunction windowFunction) {
super(windowFunction);
this.aggFunction = aggFunction;
}
@Override
public void apply(K key, W window, Iterable values, Collector out) throws Exception {
ACC acc = aggFunction.createAccumulator();
for (T val : values) {
acc = aggFunction.add(val, acc);
}
wrappedFunction.apply(key, window, Collections.singletonList(aggFunction.getResult(acc)), out);
}
}