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< title > ActiveMQ JMS Transactional Session Example< / title >
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< h1 > JMS Transactional Session Example< / h1 >
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< p > This example shows you how to use a transacted Session with ActiveMQ.< / p >
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< p > Firstly 2 messages are sent via the transacted sending session before being committed. This ensures that both message
are sent< / p >
< p > Secondly the receiving session receives the messages firstly demonstrating a message being redelivered after the session
being rolled back and then acknowledging receipt of the messages via the commit method.< / p >
< h2 > Example step-by-step< / h2 >
< p > < i > To run the example, simply type < code > mvn verify< / code > from this directory< / i > < / p >
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< li > First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get it's properties from the < code > client-jndi.properties< / code > file in the directory < code > ../common/config< / code > < / li >
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< code > initialContext = getContext();< / code >
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< li > We look-up the JMS queue object from JNDI< / li >
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< code > Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");< / code >
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< li > We look-up the JMS connection factory object from JNDI< / li >
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< code > ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");< / code >
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< li > We create a JMS connection< / li >
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< code > connection = cf.createConnection();< / code >
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< li > We start the connection. In order for delivery to occur on any consumers or subscribers on a connection, the connection must be started< / li >
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< code > connection.start();< / code >
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< li > We create a JMS session. The session is created as transacted.< / li >
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< code > Session session = connection.createSession(true, Session.SESSION_TRANSACTED);< / code >
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< li > We create a JMS message producer on the session. This will be used to send the messages.< / li >
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< code > MessageProducer messageProducer = session.createProducer(queue);< / code >
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< li > We create a message consumer< / li >
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< code > MessageConsumer messageConsumer = session.createConsumer(queue);< / code >
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< li > We create 2 text messages< / li >
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< code > TextMessage message1 = session.createTextMessage("This is a text message1");< / code >
< code > TextMessage message2 = session.createTextMessage("This is a text message2");< / code >
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< li > We send the text messages to the queue< / li >
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< code > messageProducer.send(message1);< / code >
< code > messageProducer.send(message2);< / code >
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< li > We receive the message, it will return null as the transaction is not committed.< / li >
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< code > TextMessage receivedMessage = (TextMessage) messageConsumer.receive(5000);< / code >
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< li > We commit the session< / li >
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< code > session.commit();< / code >
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< li > We receive the messages again< / li >
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< code > receivedMessage = (TextMessage) messageConsumer.receive(5000);< / code >
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< li > We roll back the session, this will cause the received message canceled and redelivered again< / li >
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< code > session.rollback();< / code >
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< li > We receive the message again, we will get two messages. Nothing more, nothing less< / li >
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< code > receivedMessage = (TextMessage) messageConsumer.receive(5000);< / code >
< code > receivedMessage = (TextMessage) messageConsumer.receive(5000);< / code >
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< li > We commit the session< / li >
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< code > session.commit();< / code >
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< li > We receive the message again. Nothing should be received< / li >
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< code > receivedMessage = (TextMessage) messageConsumer.receive(5000);< / code >
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< li > And finally, < b > always< / b > remember to close your JMS connections and resources after use, in a < code > finally< / code > block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects< / li >
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< code > finally
{
if (initialContext != null)
{
initialContext.close();
}
if (connection != null)
{
connection.close();
}
}< / code >
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