kafka Reducer 源码
kafka Reducer 代码
文件路径：/streams/src/main/java/org/apache/kafka/streams/kstream/Reducer.java
/*
* 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.kafka.streams.kstream;
import org.apache.kafka.streams.KeyValue;
/**
* The {@code Reducer} interface for combining two values of the same type into a new value.
* In contrast to {@link Aggregator} the result type must be the same as the input type.
* <p>
* The provided values can be either original values from input {@link KeyValue} pair records or be a previously
* computed result from {@link Reducer#apply(Object, Object)}.
* <p>
* {@code Reducer} can be used to implement aggregation functions like sum, min, or max.
*
* @param <V> value type
* @see KGroupedStream#reduce(Reducer)
* @see KGroupedStream#reduce(Reducer, Materialized)
* @see TimeWindowedKStream#reduce(Reducer)
* @see TimeWindowedKStream#reduce(Reducer, Materialized)
* @see SessionWindowedKStream#reduce(Reducer)
* @see SessionWindowedKStream#reduce(Reducer, Materialized)
* @see Aggregator
*/
public interface Reducer<V> {
/**
* Aggregate the two given values into a single one.
*
* @param value1 the first value for the aggregation
* @param value2 the second value for the aggregation
* @return the aggregated value
*/
V apply(final V value1, final V value2);
}
相关信息
相关文章
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
7、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦