Package dk.netarkivet.common.distribute

Class JMSConnection

  • All Implemented Interfaces:
    CleanupIF, javax.jms.ExceptionListener
    Direct Known Subclasses:
    JMSConnectionMockupMQ, JMSConnectionSunMQ
    public abstract class JMSConnection
extends Object
implements javax.jms.ExceptionListener, CleanupIF
    Handles the communication with a JMS broker. Note on Thread-safety: the methods and fields of JMSConnection are not accessed by multiple threads (though JMSConnection itself creates threads). Thus no synchronization is needed on methods and fields of JMSConnection. A shutdown hook is also added, which closes the connection. Class JMSConnection is now also a exceptionhandler for the JMS Connections

    • Field Detail

      • CONSUMER_KEY_SEPARATOR

        protected static final String CONSUMER_KEY_SEPARATOR
        Separator used in the consumer key. Separates the ChannelName from the MessageListener.toString().
        See Also:
        Constant Field Values

      • connection

        protected javax.jms.Connection connection
        The JMS Connection.

      • session

        protected javax.jms.Session session
        The Session handling messages sent to / received from the NetarchiveSuite queues and topics.

      • producers

        protected final Map<String,​javax.jms.MessageProducer> producers
        Map for caching message producers.

      • consumers

        protected final Map<String,​javax.jms.MessageConsumer> consumers
        Map for caching message consumers (topic-subscribers and queue-receivers).

      • listeners

        protected final Map<String,​javax.jms.MessageListener> listeners
        Map for caching message listeners (topic-subscribers and queue-receivers).

      • connectionLock

        protected final ReentrantReadWriteLock connectionLock
        Lock for the connection. Locked for read on adding/removing listeners and sending messages. Locked for write when connection, releasing and reconnecting.

      • closeHook

        protected Thread closeHook
        Shutdown hook that closes the JMS connection.

      • instance

        protected static JMSConnection instance
        Singleton pattern is be used for this class. This is the one and only instance.

    • Constructor Detail

      • JMSConnection

        protected JMSConnection()
        Class constructor.

    • Method Detail

      • getConnectionFactory

        protected abstract javax.jms.ConnectionFactory getConnectionFactory()
                                                             throws javax.jms.JMSException
        Should be implemented according to a specific JMS broker.
        Returns:
        QueueConnectionFactory
        Throws:
        javax.jms.JMSException - If unable to get QueueConnectionFactory

      • getDestination

        protected abstract javax.jms.Destination getDestination​(String destinationName)
                                                 throws javax.jms.JMSException
        Should be implemented according to a specific JMS broker.
        Parameters:
        destinationName - the name of the wanted Queue
        Returns:
        The destination. Note that the implementation should make sure that this is a Queue or a Topic, as required by the NetarchiveSuite design. Channels.isTopic(String)
        Throws:
        javax.jms.JMSException - If unable to get a destination.

      • onException

        public abstract void onException​(javax.jms.JMSException e)
        Exceptionhandler for the JMSConnection. Implemented according to a specific JMS broker. Should try to reconnect if at all possible.
        Specified by:
        onException in interface javax.jms.ExceptionListener
        Parameters:
        e - a JMSException

      • initConnection

        protected void initConnection()
                       throws IOFailure
        Initializes the JMS connection. Creates and starts connection and session. Adds a shutdown hook that closes down JMSConnection. Adds this object as ExceptionListener for the connection.
        Throws:
        IOFailure - if initialization fails.

      • send

        public void send​(NetarkivetMessage msg)
        Submit an object to the destination queue. This method shouldn't be overridden. Override the method sendMessage to change functionality.
        Parameters:
        msg - The NetarkivetMessage to send to the destination queue (null not allowed)
        Throws:
        ArgumentNotValid - if nMsg is null.
        IOFailure - if the operation failed.

      • resend

        public final void resend​(NetarkivetMessage msg,
                         ChannelID to)
        Sends a message msg to the channel defined by the parameter to - NOT the channel defined in the message.
        Parameters:
        msg - Message to be sent
        to - The destination channel

      • reply

        public final void reply​(NetarkivetMessage msg)
        Submit an object to the reply queue.
        Parameters:
        msg - The NetarkivetMessage to send to the reply queue (null not allowed)
        Throws:
        ArgumentNotValid - if nMsg is null.
        PermissionDenied - if message nMsg has not been sent yet.
        IOFailure - if unable to reply.

      • setListener

        public void setListener​(ChannelID mq,
                        javax.jms.MessageListener ml)
                 throws IOFailure
        Method adds a listener to the given queue or topic.
        Parameters:
        mq - the messagequeue to listen to
        ml - the messagelistener
        Throws:
        IOFailure - if the operation failed.

      • removeListener

        public void removeListener​(ChannelID mq,
                           javax.jms.MessageListener ml)
                    throws IOFailure
        Removes the specified MessageListener from the given queue or topic.
        Parameters:
        mq - the given queue or topic
        ml - a messagelistener
        Throws:
        IOFailure - On network trouble

      • createQueueBrowser

        public javax.jms.QueueBrowser createQueueBrowser​(ChannelID queueID)
                                          throws javax.jms.JMSException
        Creates a QueueBrowser object to peek at the messages on the specified queue.
        Parameters:
        queueID - The ChannelID for a specified queue.
        Returns:
        A new QueueBrowser instance with access to the specified queue
        Throws:
        javax.jms.JMSException - If unable to create the specified queue browser

      • createQueueBrowser

        public javax.jms.QueueBrowser createQueueBrowser​(ChannelID queueID,
                                                 javax.jms.QueueSession QSession)
                                          throws javax.jms.JMSException
        Creates a QueueBrowser object to peek at the messages on the specified queue.
        Parameters:
        queueID - The ChannelID for a specified queue.
        QSession - The QueueSession to use.
        Returns:
        A new QueueBrowser instance with access to the specified queue
        Throws:
        javax.jms.JMSException - If unable to create the specified queue browser

      • getQueueSession

        public abstract javax.jms.QueueSession getQueueSession()
                                                throws javax.jms.JMSException
        Provides a QueueSession instance. Functionality for retrieving a QueueSession object isen't available on the generic JMSConnectionFactory
        Returns:
        A QueueSession object connected to the current JMS broker
        Throws:
        javax.jms.JMSException - Failure to retrieve the QueueBrowser JMS Browser

      • cleanup

        public void cleanup()
        Clean up. Remove close connection, remove shutdown hook and null the instance.
        Specified by:
        cleanup in interface CleanupIF

      • unpack

        public static NetarkivetMessage unpack​(javax.jms.Message msg)
                                throws ArgumentNotValid
        Unwraps a NetarkivetMessage from an ObjectMessage.
        Parameters:
        msg - a javax.jms.ObjectMessage
        Returns:
        a NetarkivetMessage
        Throws:
        ArgumentNotValid - when msg in valid or format of JMS Object message is invalid

      • sendMessage

        protected void sendMessage​(NetarkivetMessage nMsg,
                           ChannelID to)
                    throws IOFailure
        Submit an ObjectMessage to the destination channel.
        Parameters:
        nMsg - the NetarkivetMessage to be wrapped and send as an ObjectMessage
        to - the destination channel
        Throws:
        IOFailure - if message failed to be sent.

      • reconnect

        protected void reconnect()
        Do a reconnect to the JMSbroker. Does absolutely nothing, if already in the process of reconnecting.

      • getConsumerKey

        protected static String getConsumerKey​(String channel,
                                       javax.jms.MessageListener messageListener)
        Generate a consumerkey based on the given channel name and messageListener.
        Parameters:
        channel - Channel name
        messageListener - a messageListener
        Returns:
        the generated consumerkey.