content: /*
   * 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.integration;
  
  import org.apache.kafka.common.serialization.Serdes;
  import org.apache.kafka.common.serialization.StringDeserializer;
  import org.apache.kafka.common.serialization.StringSerializer;
  import org.apache.kafka.streams.KeyValue;
  import org.apache.kafka.streams.StreamsBuilder;
  import org.apache.kafka.streams.StreamsConfig;
  import org.apache.kafka.streams.TestInputTopic;
  import org.apache.kafka.streams.TestOutputTopic;
  import org.apache.kafka.streams.TopologyTestDriver;
  import org.apache.kafka.streams.kstream.GlobalKTable;
  import org.apache.kafka.streams.kstream.JoinWindows;
  import org.apache.kafka.streams.kstream.KStream;
  import org.apache.kafka.streams.kstream.ValueJoiner;
  
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import java.time.Duration;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Properties;
  
  import static org.apache.kafka.streams.kstream.JoinWindows.ofTimeDifferenceAndGrace;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  public class RelaxedNullKeyRequirementJoinTest {
  
      private static final JoinWindows WINDOW = ofTimeDifferenceAndGrace(Duration.ofSeconds(60), Duration.ofSeconds(10));
      private static final ValueJoiner<String, String, String> JOINER = (lv, rv) -> lv + "|" + rv;
      private static final String LEFT = "left";
      private static final String RIGHT = "right";
      private static final String OUT = "out";
      private TopologyTestDriver testDriver;
      private StreamsBuilder builder;
      private KStream<String, String> leftStream;
      private KStream<String, String> rightStream;
      private TestInputTopic<String, String> left;
      private TestInputTopic<String, String> right;
      private TestOutputTopic<String, String> out;
  
      @BeforeEach
      void beforeEach() {
          builder = new StreamsBuilder();
          leftStream = builder.<String, String>stream(LEFT).repartition();
          rightStream = builder.<String, String>stream(RIGHT).repartition();
      }
  
      @AfterEach
      void afterEach() {
          testDriver.close();
      }
  
      @Test
      void testRelaxedLeftStreamStreamJoin() {
          leftStream
              .leftJoin(rightStream, JOINER, WINDOW)
              .to(OUT);
          initTopology();
          left.pipeInput(null, "leftValue", 1);
          assertEquals(Collections.singletonList(new KeyValue<>(null, "leftValue|null")), out.readKeyValuesToList());
      }
  
      @Test
      void testRelaxedLeftStreamTableJoin() {
          leftStream
              .leftJoin(rightStream.toTable(), JOINER)
              .to(OUT);
          initTopology();
          left.pipeInput(null, "leftValue", 1);
          assertEquals(Collections.singletonList(new KeyValue<>(null, "leftValue|null")), out.readKeyValuesToList());
      }
  
      @Test
      void testRelaxedOuterStreamStreamJoin() {
          leftStream
              .outerJoin(rightStream, JOINER, WINDOW)
              .to(OUT);
          initTopology();
          right.pipeInput(null, "rightValue", 1);
          left.pipeInput(null, "leftValue");
          assertEquals(
              Arrays.asList(new KeyValue<>(null, "null|rightValue"), new KeyValue<>(null, "leftValue|null")),
              out.readKeyValuesToList()
          );
      }
  
      @Test
      void testRelaxedLeftStreamGlobalTableJoin() {
          final GlobalKTable<String, String> global = builder.globalTable("global");
          leftStream
              .leftJoin(global, (key, value) -> null, JOINER)
              .to(OUT);
          initTopology();
          left.pipeInput(null, "leftValue", 1);
          assertEquals(Collections.singletonList(new KeyValue<>(null, "leftValue|null")), out.readKeyValuesToList());
      }
  
      @Test
      void testDropNullKeyRecordsForRepartitionNodesWithNoRelaxedJoinDownstream() {
          leftStream
              .repartition()
              .to(OUT);
          initTopology();
          left.pipeInput(null, "leftValue", 1);
          assertEquals(Collections.emptyList(), out.readKeyValuesToList());
      }
  
      private void initTopology() {
          testDriver = new TopologyTestDriver(builder.build(), props());
          left = testDriver.createInputTopic(
              LEFT,
              new StringSerializer(),
              new StringSerializer()
          );
          right = testDriver.createInputTopic(
              RIGHT,
              new StringSerializer(),
              new StringSerializer()
          );
          out = testDriver.createOutputTopic(
              OUT,
              new StringDeserializer(),
              new StringDeserializer()
          );
      }
  
      private static Properties props() {
          final Properties props = new Properties();
          props.setProperty(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
          props.setProperty(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
          return props;
      }
  }
  