Messaging

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>at.aydin.academy</groupId>
        <artifactId>07messaging-pair</artifactId>
        <version>1.0.0</version>
        <relativePath>../pom.xml</relativePath>
    </parent>
    <artifactId>messaging-legacy</artifactId>
    <packaging>jar</packaging>
    <name>Messaging Legacy (JMS / ActiveMQ Classic)</name>
    <dependencies>
        <dependency>
            <groupId>org.apache.activemq</groupId>
            <artifactId>activemq-broker</artifactId>
            <version>${activemq.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.activemq</groupId>
            <artifactId>activemq-client</artifactId>
            <version>${activemq.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.jms</groupId>
            <artifactId>javax.jms-api</artifactId>
            <version>2.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
            </plugin>

        </plugins>
    </build>
</project>

package at.aydin.lab.messaging.legacy;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.broker.BrokerService;

public final class MessagingLegacyApplication {
    private MessagingLegacyApplication() {
    }

    public static void main(String[] args) throws Exception {
        BrokerService broker = new BrokerService();
        broker.setBrokerName("legacy-demo");
        broker.setPersistent(false);
        broker.addConnector("vm://legacy-demo");
        broker.start();
        try {
            LegacyJmsGateway gateway = new LegacyJmsGateway(new ActiveMQConnectionFactory("vm://legacy-demo?create=false"));
            gateway.send("orders", "ORDER-1001");
            System.out.println("Empfangen: " + gateway.receive("orders", 2000));
        } finally {
            broker.stop();
        }
    }
}

package at.aydin.lab.messaging.legacy;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;

// Design Pattern: Messaging Gateway
// Zweck: JMS-Infrastruktur wird hinter einfachen Sende-/Empfangsmethoden gekapselt.
public final class LegacyJmsGateway {
    private final ConnectionFactory connectionFactory;
    public LegacyJmsGateway(ConnectionFactory connectionFactory) {
        this.connectionFactory = connectionFactory;
    }

    public void send(String queueName, String payload) throws Exception {
        try (Connection connection = connectionFactory.createConnection(); Session session = connection.createSession(false,
            Session.AUTO_ACKNOWLEDGE)) {
            Queue queue = session.createQueue(queueName);
            try (MessageProducer producer = session.createProducer(queue)) {
                producer.send(session.createTextMessage(payload));
            }
        }
    }

    public String receive(String queueName, long timeoutMillis) throws Exception {
        try (Connection connection = connectionFactory.createConnection(); Session session = connection.createSession(false,
            Session.AUTO_ACKNOWLEDGE)) {
            connection.start();
            Queue queue = session.createQueue(queueName);
            try (MessageConsumer consumer = session.createConsumer(queue)) {
                return ((TextMessage) consumer.receive(timeoutMillis)).getText();
            }
        }
    }
}

package at.aydin.lab.messaging.legacy;

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;

class MessagingContractTest {
    @Test
    void queueNameIsStable() {
        assertEquals("orders", "orders");
    }
}