Exchange Direct untuk Routing

Introduction to Direct Exchange

What is a Routing Key?

How Direct Exchange Works

Producer's Role: Sending with Keys

Consumer's Role: Binding with Keys

Code: Producer Setup & Declare

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class DirectProducerSetup {
    private static final String EXCHANGE_NAME = "direct_logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost"); // Assuming RabbitMQ is local

        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {

            channel.exchangeDeclare(EXCHANGE_NAME, "direct");
            System.out.println("Exchange '" + EXCHANGE_NAME + "' declared.");

            // In a real app, you'd send messages here
            // For this setup example, we just declare.
        }
    }
}

Code: Producer Sending Message

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import java.nio.charset.StandardCharsets;

public class DirectProducerSend {
    private static final String EXCHANGE_NAME = "direct_logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost"); // Assuming RabbitMQ is local

        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {

            channel.exchangeDeclare(EXCHANGE_NAME, "direct"); // Ensure exchange exists

            String routingKey = "error";
            String message = "A critical error occurred!";

            channel.basicPublish(EXCHANGE_NAME, routingKey, null, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + routingKey + ":'" + message + "'");
        }
    }
}

Code: Consumer Setup & Binding

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;

public class DirectConsumerError {
    private static final String EXCHANGE_NAME = "direct_logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost"); // Assuming RabbitMQ is local

        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, "direct");

        String queueName = channel.queueDeclare().getQueue(); // Create a non-durable, exclusive, auto-delete queue
        String bindingKey = "error";
        channel.queueBind(queueName, EXCHANGE_NAME, bindingKey);

        System.out.println(" [*] Waiting for messages with routing key '" + bindingKey + "'. To exit press CTRL+C");

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + delivery.getEnvelope().getRoutingKey() + ":'" + message + "'");
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});
    }
}

Multiple Bindings & Use Cases

Quick Check: Direct Routing

Recap: Direct Exchange