JsonConnection.java

/*
 * Copyright 2012-2014 Nikolay A. Viguro
 * <p/>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package ru.iris.common.messaging;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import ru.iris.common.Config;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

/**
 * Prototype for JSON message broadcasting.
 *
 * @author Nikolay A. Viguro, Tommi S.E. Laukkanen
 */

public class JsonConnection
{

	private static final Logger LOGGER = LogManager.getLogger(JsonConnection.class);

	private Channel channel;

	/**
	 * Singleton (On Demand Holder)
	 */
	public static class SingletonHolder
	{
		public static final JsonConnection HOLDER_INSTANCE = new JsonConnection();
	}

	public static JsonConnection getInstance()
	{
		return SingletonHolder.HOLDER_INSTANCE;
	}

	public JsonConnection()
	{
		// Create a ConnectionFactory
		ConnectionFactory connectionFactory = new ConnectionFactory();

		// Create a Connection
		try
		{
			Config config = Config.getInstance();

			// Create a ConnectionFactory
			connectionFactory.setHost(config.get("AMQPhost"));
			connectionFactory.setPort(Integer.valueOf(config.get("AMQPport")));
			connectionFactory.setUsername(config.get("AMQPuser"));
			connectionFactory.setPassword(config.get("AMQPpasswd"));

			/*
	  		The AMQ connection.
	 		*/
			Connection connection = connectionFactory.newConnection();
			channel = connection.createChannel();

			// Create exchange
			channel.exchangeDeclare("iris", "topic", true);
		} catch (IOException | TimeoutException e) {
			LOGGER.error("Error while connection to AMQP broker: " + e.getMessage());
			System.exit(1);
		}
    }

	public Channel getChannel()
	{
		return channel;
	}
}