es.devcircus.rabbitmq_examples.rabbitmq_rpc.RPCServer.java Source code

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Here is the source code for es.devcircus.rabbitmq_examples.rabbitmq_rpc.RPCServer.java

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/**
 * This file is part of rabbitmq-examples.
 *
 * rabbitmq-examples is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2, or (at your option) any later version.
 *
 * rabbitmq-examples is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; see the file COPYING. If not, see
 * <http://www.gnu.org/licenses/>.
 */
package es.devcircus.rabbitmq_examples.rabbitmq_rpc;

import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.AMQP.BasicProperties;
import com.rabbitmq.client.ConsumerCancelledException;
import com.rabbitmq.client.ShutdownSignalException;
import java.io.IOException;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * @author Adrian Novegil Toledo
 * @mail adrian.novegil@gmail.com
 * @description
 */
public class RPCServer {

    private static final String RPC_QUEUE_NAME = "rpc_queue";

    /**
     *
     * @param n
     * @return
     */
    private static int fib(int n) {
        if (n == 0) {
            return 0;
        }
        if (n == 1) {
            return 1;
        }
        return fib(n - 1) + fib(n - 2);
    }

    /**
     *
     * @param argv
     */
    public static void main(String[] argv) {
        Connection connection = null;
        Channel channel = null;
        try {
            ConnectionFactory factory = new ConnectionFactory();
            //            factory.setHost("localhost");
            factory.setHost("192.168.0.202");
            //            factory.setPort(5671);

            //            factory.useSslProtocol();

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

            channel.queueDeclare(RPC_QUEUE_NAME, false, false, false, null);

            channel.basicQos(1);

            QueueingConsumer consumer = new QueueingConsumer(channel);
            channel.basicConsume(RPC_QUEUE_NAME, false, consumer);

            System.out.println(" [x] Awaiting RPC requests");

            while (true) {
                String response = null;

                QueueingConsumer.Delivery delivery = consumer.nextDelivery();

                BasicProperties props = delivery.getProperties();
                BasicProperties replyProps = new BasicProperties.Builder().correlationId(props.getCorrelationId())
                        .build();

                try {
                    String message = new String(delivery.getBody(), "UTF-8");
                    int n = Integer.parseInt(message);

                    System.out.println(" [.] fib(" + message + ")");
                    response = "" + fib(n);
                } catch (Exception e) {
                    System.out.println(" [.] " + e.toString());
                    response = "";
                } finally {
                    channel.basicPublish("", props.getReplyTo(), replyProps, response.getBytes("UTF-8"));

                    channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
                }
            }
        } catch (IOException | InterruptedException | ShutdownSignalException | ConsumerCancelledException e) {
            System.out.println(e.toString());
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (Exception ignore) {
                }
            }
        }
    }
}