package org.lsst.ccs.bus.jms;
   
   import org.lsst.ccs.utilities.logging.Logger;
   
   import javax.jms.Connection;
   import javax.jms.ConnectionFactory;
   import javax.jms.Destination;
   import javax.jms.JMSException;
   import javax.jms.MessageProducer;
  import javax.jms.Session;
  import javax.naming.Context;
  import javax.naming.InitialContext;
  import javax.naming.NamingException;
  import java.util.Properties;
  import org.lsst.ccs.bootstrap.resources.BootstrapResourceUtils;
  
  /**
   * JMS Queue session factory
   * 
   * @author aubourg
   * 
   */
  
  public class QueueSessionFactory {
  	static protected QueueSessionFactory instance = null;
  
  	public static synchronized QueueSessionFactory getSessionFactory() {
  		if (instance == null) {
  			instance = new QueueSessionFactory();
  		}
  		return instance;
  	}
  
  	static Logger log = Logger.getLogger("org.lsst.ccs.bus.jms.QueueSessionFactory");
  
  	Connection conn;
  
  	Context context;
  
  	ConnectionFactory cf;
  
  	public Session getQueueSession() {
  		try {
  			if (context == null) {
                              Properties props = BootstrapResourceUtils.getBootstrapProperties("jndi");
                              context = new InitialContext(props);
  			}
  			if (cf == null) {
  				cf = (ConnectionFactory) context.lookup("ConnectionFactory");
  			}
  			if (conn == null) {
  				conn = cf.createConnection();
  				conn.start();
  			}
  
  			Session session = conn.createSession(false,
  					Session.AUTO_ACKNOWLEDGE);
  
  			return session;
  		} catch (NamingException e1) {
  			e1.printStackTrace();
  			throw new RuntimeException(e1);
  		} catch (JMSException e2) {
  			e2.printStackTrace();
  			throw new RuntimeException(e2);
  		}
  	}
  
  	public MessageProducer getCommandReplySender(Session sess, Destination dest) {
  		try {
  			return sess.createProducer(dest);
  		} catch (JMSException e) {
  			e.printStackTrace();
  			throw new RuntimeException(e);
  		}
  	}
  
  }