initial commit

natsio/docker-compose.yaml

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+version: "3.8"
+
+services:
+  nats:
+    image: nats:2.10
+    ports:
+      - "4222:4222"
+
+  subscriber:
+    build: ./subscriber
+    depends_on:
+      - nats
+
+  publisher:
+    build: ./publisher
+    depends_on:
+      - nats

natsio/publisher/Dockerfile

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+FROM eclipse-temurin:21-jdk
+
+WORKDIR /app
+
+ADD https://repo1.maven.org/maven2/io/nats/jnats/2.16.14/jnats-2.16.14.jar nats.jar
+
+COPY Publisher.java .
+
+RUN javac -cp nats.jar Publisher.java
+
+CMD ["java", "-cp", ".:nats.jar", "Publisher"]

natsio/publisher/Publisher.java

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+import io.nats.client.Connection;
+import io.nats.client.Nats;
+import java.time.Duration;
+
+public class Publisher {
+  public static void main(String[] args) throws Exception {
+    Connection nc = Nats.connect("nats://nats:4222");
+
+    int counter = 0;
+
+    while (true) {
+      long sendTime = System.currentTimeMillis();
+      String msg = counter + "," + sendTime;
+      nc.publish("demo.subject", msg.getBytes());
+      nc.flush(Duration.ofSeconds(1));
+
+      System.out.println("Sent: " + counter);
+      counter++;
+      Thread.sleep(1000);
+    }
+  }
+}

natsio/subscriber/Dockerfile

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+FROM eclipse-temurin:21-jdk
+
+WORKDIR /app
+
+ADD https://repo1.maven.org/maven2/io/nats/jnats/2.16.14/jnats-2.16.14.jar nats.jar
+
+COPY Subscriber.java .
+
+RUN javac -cp nats.jar Subscriber.java
+
+CMD ["java", "-cp", ".:nats.jar", "Subscriber"]

natsio/subscriber/Subscriber.java

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+import io.nats.client.Connection;
+import io.nats.client.Dispatcher;
+import io.nats.client.Nats;
+
+public class Subscriber {
+  public static void main(String[] args) throws Exception {
+    Connection nc = Nats.connect("nats://nats:4222");
+
+    Dispatcher dispatcher = nc.createDispatcher(msg -> {
+      String received = new String(msg.getData()).trim();
+      String[] parts = received.split(",");
+      if (parts.length >= 2) {
+        int counter = Integer.parseInt(parts[0].trim());
+        long sendTime = Long.parseLong(parts[1].trim());
+        long latency = System.currentTimeMillis() - sendTime;
+
+        System.out.printf("Received: %d | Latency: %d ms%n", counter, latency);
+      }
+    });
+
+    dispatcher.subscribe("demo.subject");
+
+    Thread.sleep(Long.MAX_VALUE);
+  }
+}