Bael 1421 (#3312)

* BAEL-1421 live test of kafka streams

* BAEL-1421 Removed not-needed dependency

* BAEL-1421 rearannge

* BAEL-1421 rearannge

* fix pom

* move to libraries-data

* move to libraries-data

libraries-data/pom.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <parent>
         <groupId>com.baeldung</groupId>
@@ -41,6 +42,29 @@
             <artifactId>ormlite-jdbc</artifactId>
             <version>${ormlite.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.apache.kafka</groupId>
+            <artifactId>kafka-streams</artifactId>
+            <version>${kafka.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.kafka</groupId>
+            <artifactId>kafka-clients</artifactId>
+            <version>${kafka.version}</version>
+            <exclusions>
+                <exclusion>
+                    <groupId>org.slf4j</groupId>
+                    <artifactId>slf4j-log4j12</artifactId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.kafka</groupId>
+            <artifactId>kafka-clients</artifactId>
+            <version>${kafka.version}</version>
+            <classifier>test</classifier>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -143,6 +167,12 @@
         </plugins>
     </build>
 
+    <repositories>
+        <repository>
+            <id>Apache Staging</id>
+            <url>https://repository.apache.org/content/groups/staging</url>
+        </repository>
+    </repositories>
     <properties>
         <kryo.version>4.0.1</kryo.version>
         <h2.version>1.4.196</h2.version>
@@ -150,5 +180,6 @@
         <junit.version>4.12</junit.version>
         <maven-compiler-plugin.version>3.6.2</maven-compiler-plugin.version>
         <ormlite.version>5.0</ormlite.version>
+        <kafka.version>1.0.0</kafka.version>
     </properties>
 </project>

libraries-data/src/test/java/com/baeldung/kafkastreams/KafkaStreamsLiveTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.kafkastreams;
+
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.common.serialization.Serde;
+import org.apache.kafka.common.serialization.Serdes;
+import org.apache.kafka.streams.KafkaStreams;
+import org.apache.kafka.streams.StreamsConfig;
+import org.apache.kafka.streams.kstream.KStream;
+import org.apache.kafka.streams.kstream.KStreamBuilder;
+import org.apache.kafka.streams.kstream.KTable;
+import org.apache.kafka.test.TestUtils;
+import org.junit.Ignore;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Properties;
+import java.util.regex.Pattern;
+
+public class KafkaStreamsLiveTest {
+    private String bootstrapServers = "localhost:9092";
+
+    @Test
+    @Ignore("it needs to have kafka broker running on local")
+    public void shouldTestKafkaStreams() throws InterruptedException {
+        //given
+        String inputTopic = "inputTopic";
+
+        Properties streamsConfiguration = new Properties();
+        streamsConfiguration.put(StreamsConfig.APPLICATION_ID_CONFIG, "wordcount-live-test");
+        streamsConfiguration.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
+        streamsConfiguration.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
+        streamsConfiguration.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass().getName());
+        streamsConfiguration.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 1000);
+        streamsConfiguration.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+        // Use a temporary directory for storing state, which will be automatically removed after the test.
+        streamsConfiguration.put(StreamsConfig.STATE_DIR_CONFIG, TestUtils.tempDirectory().getAbsolutePath());
+
+        //when
+        KStreamBuilder builder = new KStreamBuilder();
+        KStream<String, String> textLines = builder.stream(inputTopic);
+        Pattern pattern = Pattern.compile("\\W+", Pattern.UNICODE_CHARACTER_CLASS);
+
+        KTable<String, Long> wordCounts = textLines
+                .flatMapValues(value -> Arrays.asList(pattern.split(value.toLowerCase())))
+                .groupBy((key, word) -> word)
+                .count();
+
+        wordCounts.foreach((word, count) -> System.out.println("word: " + word + " -> " + count));
+
+        String outputTopic = "outputTopic";
+        final Serde<String> stringSerde = Serdes.String();
+        final Serde<Long> longSerde = Serdes.Long();
+        wordCounts.to(stringSerde, longSerde, outputTopic);
+
+        KafkaStreams streams = new KafkaStreams(builder, streamsConfiguration);
+        streams.start();
+
+        //then
+        Thread.sleep(30000);
+        streams.close();
+    }
+}