edu.jhu.pha.vospace.QueueConnector.java Source code

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Here is the source code for edu.jhu.pha.vospace.QueueConnector.java

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/*******************************************************************************
 * Copyright 2013 Johns Hopkins University
 * 
 * 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
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * 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 edu.jhu.pha.vospace;

import java.io.IOException;

import org.apache.commons.configuration.Configuration;
import org.apache.log4j.Logger;

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

public class QueueConnector {
    static Configuration conf = SettingsServlet.getConfig();
    private static final Logger logger = Logger.getLogger(QueueConnector.class);
    //RabbitMQ
    private static ConnectionFactory factory;

    static {
        factory = new ConnectionFactory();
        factory.setHost(conf.getString("rabbitmq.host"));
        factory.setVirtualHost(conf.getString("rabbitmq.vhost"));
    }

    /** Helper class for goAMQP() */
    public static abstract class AMQPWorker<T> {
        abstract public T go(Connection conn, Channel channel) throws IOException;

        public void error(String context, Exception e) {
            logger.error(context, e);
        }
    }

    /** Helper function to setup and teardown AMQP connection & statement. */
    public static <T> T goAMQP(String context, AMQPWorker<T> goer) {
        logger.debug("AMPQ " + context);
        Connection conn = null;
        Channel channel = null;
        try {
            conn = factory.newConnection();
            channel = conn.createChannel();
            T result = goer.go(conn, channel);
            return result;
        } catch (IOException e) {
            goer.error(context, e);
            return null;
        } finally {
            close(channel);
            close(conn);
        }
    }

    public static void close(Connection c) {
        if (c != null) {
            try {
                c.close();
            } catch (Exception ignored) {
            }
        }
    }

    public static void close(Channel c) {
        if (c != null) {
            try {
                c.close();
            } catch (Exception ignored) {
            }
        }
    }
}