plugins {
   // Apply the application plugin to add support for building a CLI application in Java.
   id 'application'
}

repositories {
   // Use Maven Central for resolving dependencies.
   mavenCentral()
}

dependencies {
    // Fluvio Java client
    implementation 'com.infinyon:fluvio:0.12.16'
}

application {
   // Define the main class for the application.
   mainClass = 'fluvio.App'
}

package fluvio;

import com.infinyon.fluvio.Fluvio;
import com.infinyon.fluvio.TopicProducer;
import com.infinyon.fluvio.PartitionConsumer;
import com.infinyon.fluvio.PartitionConsumerStream;
import com.infinyon.fluvio.Offset;
import com.infinyon.fluvio.Record;
import java.text.MessageFormat;
import java.util.*;

/**
* This is an example of a basic Fluvio workflow in Java 
*
* 1. Create a topic to store data in via CLI
* 2. Establish a connection to the Fluvio cluster
* 3. Create a producer and send some bytes
* 4. Create a consumer, and stream the data back
*/
public class App {
   public static final String TOPIC_NAME = "hello-java";
   public static final int PARTITION = 0;
   public static final int NUM_MESSAGES = 1;

   public static void main(String[] args) throws Exception {
       // Currently the Java client does not support creating topics
       // Using the fluvio CLI
       final String cmd = String.format("fluvio topic create %s", TOPIC_NAME);
       try {
           Process process = Runtime.getRuntime().exec(cmd);
       } catch (Exception e) {
           e.printStackTrace(System.err);
       }

       // Connect to cluster
       Fluvio fluvio = Fluvio.connect();

       // Produce to topic
       TopicProducer producer = fluvio.producer(TOPIC_NAME);

       for (int i = 0; i < NUM_MESSAGES; i++) {
           producer.send(String.valueOf(i).getBytes(), MessageFormat.format("Hello World! - Time is {0,time}", new Date()).getBytes());
       }

       // Consume from topic
       PartitionConsumer consumer = fluvio.consumer(TOPIC_NAME, PARTITION);
       PartitionConsumerStream stream = consumer.stream(Offset.from_end(NUM_MESSAGES - 1));
       for (int i = 0; i < NUM_MESSAGES; i++) {
           Record record = stream.next();
           System.out.printf("Consumed record, key=%s, value=%s\n", record.key_string(), record.value_string());
       }
   }
}

$ gradle run