source: trunk/src/main/java/omq/common/util/OmqConnectionFactory.java

package omq.common.util;

import java.io.IOException;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.util.Properties;

import org.apache.log4j.Logger;

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

/**
 * This class creates RabbitMQ connections
 * 
 * @author Sergi Toda <sergi.toda@estudiants.urv.cat>
 * 
 */
public class OmqConnectionFactory {
        private static final Logger logger = Logger.getLogger(OmqConnectionFactory.class.getName());

        private static Connection connection;
        private static int connectionTimeout = 2 * 1000;

        /**
         * If this class is wanted to use as a singleton class this is the init
         * function
         * 
         * @param env
         *            - environment that sets the properties needed by RabbitMQ
         * @throws KeyManagementException
         * @throws NoSuchAlgorithmException
         * @throws IOException
         */
        public static void init(Properties env) throws KeyManagementException, NoSuchAlgorithmException, IOException {
                if (connection == null) {
                        connection = getNewConnection(env);
                }
        }

        /**
         * This function returns a working connection.
         * 
         * @param env
         *            - used if it's necessary to create a new connection
         * @return workingConnection
         * @throws Exception
         */
        public static Connection getNewWorkingConnection(Properties env) throws Exception {
                Connection connection = null;
                boolean working = false;

                while (!working) {
                        try {
                                connection = getNewConnection(env);
                                working = true;
                        } catch (Exception e) {
                                logger.error(e);
                                long milis = 2000;
                                if (env != null) {
                                        milis = Long.parseLong(env.getProperty(ParameterQueue.RETRY_TIME_CONNECTION, "2000"));
                                }
                                Thread.sleep(milis);
                        }
                }

                return connection;
        }

        /**
         * This function creates a new rabbitmq connection using the properties set
         * in env
         * 
         * @param env
         *            - Properties needed to create a new connection: username,
         *            password, rabbit_host, rabbit_port, enable_ssl (optional)
         * @return new Connection
         * @throws IOException
         * @throws KeyManagementException
         * @throws NoSuchAlgorithmException
         */
        public static Connection getNewConnection(Properties env) throws IOException, KeyManagementException, NoSuchAlgorithmException {
                // Get login info of rabbitmq
                String username = env.getProperty(ParameterQueue.USER_NAME);
                String password = env.getProperty(ParameterQueue.USER_PASS);

                // Get host info of rabbimq (where it is)
                String host = env.getProperty(ParameterQueue.RABBIT_HOST);
                int port = Integer.parseInt(env.getProperty(ParameterQueue.RABBIT_PORT));

                boolean ssl = Boolean.parseBoolean(env.getProperty(ParameterQueue.ENABLE_SSL, "false"));

                // Start a new connection and channel
                ConnectionFactory factory = new ConnectionFactory();
                factory.setUsername(username);
                factory.setPassword(password);
                factory.setHost(host);
                factory.setPort(port);
                factory.setConnectionTimeout(connectionTimeout);
                if (ssl) {
                        factory.useSslProtocol();
                }

                Connection connection = factory.newConnection();
                logger.info("New connection created using: username: " + username + ", host: " + host + ", port: " + port + ", connection timeout: "
                                + connectionTimeout + " SSL enabled: " + ssl);
                return connection;
        }

        /**
         * This method creates a new channel if the singleton pattern is used
         * 
         * @return new Channel
         * @throws IOException
         */
        public static Channel getNewChannel() throws IOException {
                Channel channel = connection.createChannel();
                logger.info("New channel created using the default connection");
                return channel;
        }
}