Setting up the JMS application v42.7.3.2

After creating the queue table and queue for the message types and starting the queue, you can set up your JMS application:

1. Create a connection factory.
2. Create a connection using the connection factory.
3. Create a session using the connection.
4. Get the queue from the session.
5. Create a message producer using the session and queue to send messages.
6. Create a message consumer using the session and queue to receive messages.

Connection factory

Use the connection factory to create connections. EDBJmsConnectionFactory is an implementation of ConnectionFactory and QueueConnectionFactory, which you use to create Connection and QueueConnection. You can create a connection factory using one of the constructors of the EDBJmsConnectionFactory class. You can use all three constructors to create either a ConnectionFactory or QueueConnectionFactory.

//Constructor with connection related properties.
public EDBJmsConnectionFactory(String host, int port, String database, 
     String username, String password);
//Constructor with connection string, user name and password.
public EDBJmsConnectionFactory(String connectionString, 
     String username, String password);
//Constructor with SQL Connection.
public EDBJmsConnectionFactory(java.sql.Connection connection);

This example shows how to create a ConnectionFactory using an existing java.sql.Connection:

javax.jms.ConnectionFactory connFactory = new EDBJmsConnectionFactory(connection);

This example shows how to create a QueueConnectionFactory using a connection string, username, and password:

javax.jms.QueueConnectionFactory connFactory = new EDBJmsConnectionFactory
   ("jdbc:edb//localhost:5444/edb", "enterprisedb", "edb");

Connection

A connection is a client's active connection that can be created from the ConnectionFactory and used to create sessions. EDBJmsConnection is an implementation of Connection, and EDBJmsQueueConnection is an implementation of QueueConnection and extends EDBJmsConnection. You can create a Connection using ConnectionFactory and a QueueConnection from QueueConnectionFactory.

This example shows how to create a Connection and a QueueConnection:

//Connection from ConnectionFactory. Assuming connFactory is ConnectionFactory.
javax.jms.Connection connection = connFactory.createConnection();

////Connection from QueueConnectionFactory. Assuming connFactory is QueueConnectionFactory.
javax.jms.QueueConnection queueConnection = connFactory.createQueueConnection();

You must start a connection for the consumer to receive messages. However, a producer can send messages without starting the connection.

This example shows how to start a connection:

queueConnection.start();

You can stop a connection at any time to stop receiving messages, and you can restart it when needed. However, you can't restart a closed connection.

This example shows how to stop and close the connection:

queueConnection.stop();
queueConnection.close();

Session

A session in EDBJms is used for creating producers and consumers and for sending and receiving messages. EDBJmsSession implements the basic Session functionality, and EDBJmsQueueSession extends EDBJmsSession and implements QueueSession. A Session can be created from a Connection.

This example shows how to create a Session and a QueueSession:

// Session
javax.jms.Session session = connection.createSession(false, javax.jms.Session.AUTO_ACKNOWLEDGE);
// QueueSession
javax.jms.QueueSession session = queueConnection.createQueueSession(false, javax.jms.Session.AUTO_ACKNOWLEDGE);

You can also use a Session or QueueSession to create queues.

This example shows how to create a queue:

javax.jms.Queue queue = session.createQueue("MSG_QUEUE");

Message producer

A message producer is responsible for creating and sending messages. You create it using a session and queue. EDBJmsMessageProducer is an implementation of MessageProducer, but in most cases you use the standard MessageProducer.

This example shows how to create a message producer, create a message, and send it. To create messages of different types, see Message types.

javax.jms.MessageProducer messageProducer = session.createProducer(queue);

javax.jms.Message msg = session.createMessage();
msg.setStringProperty("myprop1", "test value 1");

messageProducer.send(msg);

Message consumer

A message consumer receives messages. You create it using a session and a queue. EDBJmsMessageConsumer is an implementation of MessageConsumer, but you'll most often use the standard MessageConsumer.

This example shows how to create a message consumer and receive a message:

javax.jms.MessageConsumer messageConsumer = session.createConsumer(queue);
      
javax.jms.Message message = messageConsumer.receive();