org.apache.flink.streaming.api.functions.windowing.AggregateApplyWindowFunction Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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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);
}
}