inponomarev commented on a change in pull request #9107: URL: https://github.com/apache/kafka/pull/9107#discussion_r548503824
########## File path: streams/src/main/java/org/apache/kafka/streams/kstream/Branched.java ########## @@ -0,0 +1,150 @@ +/* + * 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 java.util.function.Consumer; +import java.util.function.Function; + +/** + * The {@code Branched} class is used to define the optional parameters when building branches with + * {@link BranchedKStream}. + * + * @param <K> type of record key + * @param <V> type of record value + */ +public class Branched<K, V> implements NamedOperation<Branched<K, V>> { + + protected final String name; + protected final Function<? super KStream<K, V>, + ? extends KStream<K, V>> chainFunction; + protected final Consumer<? super KStream<K, V>> chainConsumer; + + protected Branched(final String name, + final Function<? super KStream<K, V>, ? extends KStream<K, V>> chainFunction, + final Consumer<? super KStream<K, V>> chainConsumer) { + this.name = name; + this.chainFunction = chainFunction; + this.chainConsumer = chainConsumer; + } + + /** + * Create an instance of {@link Branched} from an existing instance. + * + * @param branched the instance of {@link Branched} to copy + */ + protected Branched(final Branched<K, V> branched) { + this(branched.name, branched.chainFunction, branched.chainConsumer); + } + + /** + * Configure the instance of {@link Branched} with a branch name postfix. + * + * @param name the branch name postfix to be used. If {@code null} a default branch name postfix will be generated (see + * {@link BranchedKStream} description for details) + * @return {@code this} + */ + @Override + public Branched<K, V> withName(final String name) { + return new Branched<>(name, chainFunction, chainConsumer); + } + + /** + * Create an instance of {@link Branched} with provided branch name postfix. + * + * @param name the branch name postfix to be used. If {@code null}, a default branch name postfix will be generated + * (see {@link BranchedKStream} description for details) + * @param <K> key type + * @param <V> value type + * @return a new instance of {@link Branched} + */ + public static <K, V> Branched<K, V> as(final String name) { + return new Branched<>(name, null, null); + } + + /** + * Create an instance of {@link Branched} with provided chain function. + * + * @param chain A function that will be applied to the branch. If {@code null}, the identity + * {@code kStream -> kStream} function will be supposed. If this function returns Review comment: See my reply below, where we discuss `null` consumers: https://github.com/apache/kafka/pull/9107#discussion_r548515181 (in short: I agree, I think we shouldn't) ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
