BAEL-6731: Introduction to JeroMQ (#14412)

jeromq/pom.xml

@@ -0,0 +1,57 @@
+<?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">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>jeromq</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>jeromq</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.zeromq</groupId>
+            <artifactId>jeromq</artifactId>
+            <version>0.5.3</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-engine</artifactId>
+            <version>${junit-platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-console-standalone</artifactId>
+            <version>${junit-platform.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-migrationsupport</artifactId>
+            <version>${junit-jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+            <resource>
+                <directory>src/test/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+</project>
+
+

jeromq/src/test/java/com/baeldung/jeromq/DealerRouterLiveTest.java

@@ -0,0 +1,256 @@
+package com.baeldung.jeromq;
+
+import org.junit.jupiter.api.Test;
+import org.zeromq.SocketType;
+import org.zeromq.ZContext;
+import org.zeromq.ZMQ;
+
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class DealerRouterLiveTest {
+    @Test
+    public void single() throws Exception {
+        Thread brokerThread = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+
+                ZMQ.Socket broker = context.createSocket(SocketType.ROUTER);
+                broker.bind("tcp://*:5555");
+
+                String identity = broker.recvStr();
+                System.out.println(Thread.currentThread().getName() + " - Received identity " + identity);
+
+                broker.recv(0); //  Envelope delimiter
+                System.out.println(Thread.currentThread().getName() + " - Received envelope");
+                String message = broker.recvStr(0); //  Response from worker
+                System.out.println(Thread.currentThread().getName() + " - Received message " + message);
+
+                broker.sendMore(identity);
+                broker.sendMore("xxx");
+                broker.send("Hello back");
+            }
+        });
+        brokerThread.setName("broker");
+
+        Thread workerThread = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+                ZMQ.Socket worker = context.createSocket(SocketType.DEALER);
+                worker.setIdentity(Thread.currentThread().getName().getBytes(ZMQ.CHARSET));
+
+                worker.connect("tcp://localhost:5555");
+                System.out.println(Thread.currentThread().getName() + " - Connected");
+
+                worker.sendMore("");
+                worker.send("Hello " + Thread.currentThread().getName());
+                System.out.println(Thread.currentThread().getName() + " - Sent Hello");
+
+                worker.recvStr(); //  Envelope delimiter
+                System.out.println(Thread.currentThread().getName() + " - Received Envelope");
+                String workload = worker.recvStr();
+                System.out.println(Thread.currentThread().getName() + " - Received " + workload);
+            }
+        });
+        workerThread.setName("worker");
+
+        brokerThread.start();
+        workerThread.start();
+
+        workerThread.join();
+        brokerThread.join();
+    }
+
+    @Test
+    public void asynchronous() throws Exception {
+        Thread brokerThread = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+
+                ZMQ.Socket broker = context.createSocket(SocketType.ROUTER);
+                broker.bind("tcp://*:5555");
+
+                while (true) {
+                    String identity = broker.recvStr(ZMQ.DONTWAIT);
+                    System.out.println(Thread.currentThread().getName() + " - Received identity " + identity);
+
+                    if (identity == null) {
+                        try {
+                            Thread.sleep(100);
+                        } catch (InterruptedException e) {}
+                    } else {
+
+                        broker.recv(0); //  Envelope delimiter
+                        System.out.println(Thread.currentThread().getName() + " - Received envelope");
+                        String message = broker.recvStr(0); //  Response from worker
+                        System.out.println(Thread.currentThread().getName() + " - Received message " + message);
+
+                        broker.sendMore(identity);
+                        broker.sendMore("xxx");
+                        broker.send("Hello back");
+
+                        break;
+                    }
+                }
+            }
+        });
+        brokerThread.setName("broker");
+
+        Thread workerThread = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+                ZMQ.Socket worker = context.createSocket(SocketType.DEALER);
+                worker.setIdentity(Thread.currentThread().getName().getBytes(ZMQ.CHARSET));
+
+                worker.connect("tcp://localhost:5555");
+                System.out.println(Thread.currentThread().getName() + " - Connected");
+
+                worker.sendMore("");
+                worker.send("Hello " + Thread.currentThread().getName());
+                System.out.println(Thread.currentThread().getName() + " - Sent Hello");
+
+                worker.recvStr(); //  Envelope delimiter
+                System.out.println(Thread.currentThread().getName() + " - Received Envelope");
+                String workload = worker.recvStr();
+                System.out.println(Thread.currentThread().getName() + " - Received " + workload);
+            }
+        });
+        workerThread.setName("worker");
+
+        brokerThread.start();
+        workerThread.start();
+
+        workerThread.join();
+        brokerThread.join();
+    }
+
+
+    @Test
+    public void many() throws Exception {
+        Thread brokerThread = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+
+                ZMQ.Socket broker = context.createSocket(SocketType.ROUTER);
+                broker.bind("tcp://*:5555");
+
+                while (!Thread.currentThread().isInterrupted()) {
+                    String identity = broker.recvStr();
+                    System.out.println(Thread.currentThread().getName() + " - Received identity " + identity);
+
+                    broker.recv(0); //  Envelope delimiter
+                    String message = broker.recvStr(0); //  Response from worker
+                    System.out.println(Thread.currentThread().getName() + " - Received message " + message);
+
+                    broker.sendMore(identity);
+                    broker.sendMore("");
+                    broker.send("Hello back to " + identity);
+                }
+            }
+        });
+        brokerThread.setName("broker");
+
+        Set<Thread> workers = IntStream.range(0, 10)
+                .mapToObj(index -> {
+                    Thread workerThread = new Thread(() -> {
+                        try (ZContext context = new ZContext()) {
+                            ZMQ.Socket worker = context.createSocket(SocketType.DEALER);
+                            worker.setIdentity(Thread.currentThread().getName().getBytes(ZMQ.CHARSET));
+
+                            worker.connect("tcp://localhost:5555");
+                            System.out.println(Thread.currentThread().getName() + " - Connected");
+
+                            worker.sendMore("");
+                            worker.send("Hello " + Thread.currentThread().getName());
+                            System.out.println(Thread.currentThread().getName() + " - Sent Hello");
+
+                            worker.recvStr(); //  Envelope delimiter
+                            String workload = worker.recvStr();
+                            System.out.println(Thread.currentThread().getName() + " - Received " + workload);
+                        }
+                    });
+                    workerThread.setName("worker-" + index);
+
+                    return workerThread;
+                })
+                .collect(Collectors.toSet());
+
+        brokerThread.start();
+        workers.forEach(Thread::start);
+
+        for (Thread worker : workers) {
+            worker.join();
+        }
+        brokerThread.interrupt();
+    }
+
+    @Test
+    public void threaded() throws Exception {
+        Thread brokerThread = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+
+                ZMQ.Socket broker = context.createSocket(SocketType.ROUTER);
+                broker.bind("tcp://*:5555");
+
+                ExecutorService threadPool = Executors.newFixedThreadPool(5);
+                Random rng = new Random();
+
+                while (!Thread.currentThread().isInterrupted()) {
+                    String identity = broker.recvStr();
+                    System.out.println(Thread.currentThread().getName() + " - Received identity " + identity);
+
+                    broker.recv(0); //  Envelope delimiter
+                    String message = broker.recvStr(0); //  Response from worker
+                    System.out.println(Thread.currentThread().getName() + " - Received message " + message);
+
+                    threadPool.submit(() -> {
+                        try {
+                            Thread.sleep(rng.nextInt(1000) + 1000 );
+                        } catch (Exception e) {}
+
+                        synchronized(broker) {
+                            broker.sendMore(identity);
+                            broker.sendMore("");
+                            broker.send("Hello back to " + identity + " from " + Thread.currentThread().getName());
+                        }
+                    });
+                }
+
+                threadPool.shutdown();
+            }
+        });
+        brokerThread.setName("broker");
+
+        Set<Thread> workers = IntStream.range(0, 10)
+                .mapToObj(index -> {
+                    Thread workerThread = new Thread(() -> {
+                        try (ZContext context = new ZContext()) {
+                            ZMQ.Socket worker = context.createSocket(SocketType.DEALER);
+                            worker.setIdentity(Thread.currentThread().getName().getBytes(ZMQ.CHARSET));
+
+                            worker.connect("tcp://localhost:5555");
+                            System.out.println(Thread.currentThread().getName() + " - Connected");
+
+                            worker.sendMore("");
+                            worker.send("Hello " + Thread.currentThread().getName());
+                            System.out.println(Thread.currentThread().getName() + " - Sent Hello");
+
+                            worker.recvStr(); //  Envelope delimiter
+                            String workload = worker.recvStr();
+                            System.out.println(Thread.currentThread().getName() + " - Received " + workload);
+                        }
+                    });
+                    workerThread.setName("worker-" + index);
+
+                    return workerThread;
+                })
+                .collect(Collectors.toSet());
+
+        brokerThread.start();
+        workers.forEach(Thread::start);
+
+        for (Thread worker : workers) {
+            worker.join();
+        }
+        brokerThread.interrupt();
+    }
+}

jeromq/src/test/java/com/baeldung/jeromq/PubSubLiveTest.java

@@ -0,0 +1,101 @@
+package com.baeldung.jeromq;
+
+import org.junit.jupiter.api.Test;
+import org.zeromq.SocketType;
+import org.zeromq.ZContext;
+import org.zeromq.ZMQ;
+
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class PubSubLiveTest {
+    @Test
+    public void singleSub() throws Exception {
+        Thread server = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+                ZMQ.Socket pub = context.createSocket(SocketType.PUB);
+                pub.bind("tcp://*:5555");
+
+                try {
+                    Thread.sleep(3000);
+                } catch (InterruptedException e) {}
+
+                System.out.println(Thread.currentThread().getName() + " - Sending");
+                pub.send("Hello");
+            }
+        });
+        server.setName("server");
+
+        Thread client = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+                ZMQ.Socket sub = context.createSocket(SocketType.SUB);
+                sub.connect("tcp://localhost:5555");
+                System.out.println(Thread.currentThread().getName() + " - Connected");
+
+                sub.subscribe("".getBytes());
+                System.out.println(Thread.currentThread().getName() + " - Subscribed");
+
+                String message = sub.recvStr();
+                System.out.println(Thread.currentThread().getName() + " - " + message);
+            }
+        });
+        client.setName("client");
+
+        server.start();
+        client.start();
+
+        client.join();
+        server.join();
+    }
+
+
+    @Test
+    public void manySub() throws Exception {
+        Thread server = new Thread(() -> {
+            try (ZContext context = new ZContext()) {
+                ZMQ.Socket pub = context.createSocket(SocketType.PUB);
+                pub.bind("tcp://*:5555");
+
+                try {
+                    Thread.sleep(3000);
+                } catch (InterruptedException e) {}
+
+                System.out.println(Thread.currentThread().getName() + " - Sending");
+                pub.send("Hello");
+            }
+        });
+        server.setName("server");
+
+        Set<Thread> clients = IntStream.range(0, 10)
+                .mapToObj(index -> {
+                    Thread client = new Thread(() -> {
+                        try (ZContext context = new ZContext()) {
+                            ZMQ.Socket sub = context.createSocket(SocketType.SUB);
+                            sub.connect("tcp://localhost:5555");
+                            System.out.println(Thread.currentThread().getName() + " - Connected");
+
+                            sub.subscribe("".getBytes());
+                            System.out.println(Thread.currentThread().getName() + " - Subscribed");
+
+                            String message = sub.recvStr();
+                            System.out.println(Thread.currentThread().getName() + " - " + message);
+                        }
+                    });
+                    client.setName("client-" + index);
+
+                    return client;
+                })
+                .collect(Collectors.toSet());
+
+
+        server.start();
+        clients.forEach(Thread::start);
+
+        for (Thread client : clients) {
+            client.join();
+        }
+
+        server.join();
+    }
+}

jeromq/src/test/java/com/baeldung/jeromq/RequestResponseLiveTest.java

@@ -0,0 +1,96 @@
+package com.baeldung.jeromq;
+
+import org.junit.jupiter.api.Test;
+import org.zeromq.SocketType;
+import org.zeromq.ZContext;
+import org.zeromq.ZMQ;
+
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+public class RequestResponseLiveTest {
+    @Test
+    public void requestResponse() throws Exception {
+        try (ZContext context = new ZContext()) {
+            Thread server = new Thread(() -> {
+                ZMQ.Socket socket = context.createSocket(SocketType.REP);
+                socket.bind("inproc://test");
+
+                while (!Thread.currentThread().isInterrupted()) {
+                    byte[] reply = socket.recv(0);
+                    System.out.println("Server Received " + ": [" + new String(reply, ZMQ.CHARSET) + "]");
+
+                    String response = new String(reply, ZMQ.CHARSET) + ", world";
+                    socket.send(response.getBytes(ZMQ.CHARSET), 0);
+                }
+            });
+
+            Thread client = new Thread(() -> {
+                ZMQ.Socket socket = context.createSocket(SocketType.REQ);
+                socket.connect("inproc://test");
+
+                for (int requestNbr = 0; requestNbr != 10; requestNbr++) {
+                    String request = "Hello " + requestNbr;
+                    System.out.println("Sending " + request);
+                    socket.send(request.getBytes(ZMQ.CHARSET), 0);
+
+                    byte[] reply = socket.recv(0);
+                    System.out.println("Client Received " + new String(reply, ZMQ.CHARSET));
+                }
+
+            });
+
+            server.start();
+            client.start();
+
+            client.join();
+            server.interrupt();
+        }
+    }
+
+    @Test
+    public void manyRequestResponse() throws Exception {
+        try (ZContext context = new ZContext()) {
+            Thread server = new Thread(() -> {
+                ZMQ.Socket socket = context.createSocket(SocketType.REP);
+                socket.bind("tcp://*:5555");
+
+                while (!Thread.currentThread().isInterrupted()) {
+                    byte[] reply = socket.recv(0);
+                    System.out.println("Server Received " + ": [" + new String(reply, ZMQ.CHARSET) + "]");
+
+                    String response = new String(reply, ZMQ.CHARSET) + ", world";
+                    socket.send(response.getBytes(ZMQ.CHARSET), 0);
+                }
+            });
+
+            Set<Thread> clients = IntStream.range(0, 10).mapToObj(index ->
+                    new Thread(() -> {
+                        ZMQ.Socket socket = context.createSocket(SocketType.REQ);
+                        socket.connect("tcp://localhost:5555");
+
+                        for (int requestNbr = 0; requestNbr != 10; requestNbr++) {
+                            String request = "Hello " + index + " - " + requestNbr;
+                            System.out.println("Sending " + request);
+                            socket.send(request.getBytes(ZMQ.CHARSET), 0);
+
+                            byte[] reply = socket.recv(0);
+                            System.out.println("Client " + index + " Received " + new String(reply, ZMQ.CHARSET));
+                        }
+
+                    })
+            ).collect(Collectors.toSet());
+
+            server.start();
+            clients.forEach(Thread::start);
+
+            for (Thread client : clients) {
+                client.join();
+            }
+
+            server.interrupt();
+        }
+
+    }
+}

pom.xml

@@ -369,6 +369,7 @@
                 <module>persistence-modules/spring-data-cassandra-reactive</module> <!--JAVA-21844-->
                 <module>persistence-modules/spring-data-neo4j</module>
                 <module>java-nashorn</module>
+                <module>jeromq</module>
             </modules>
 
         </profile>