JMS

JMS

1. Messaging

   • exchange data across applications or components inside an app

2. components

   • sender
   • receiver
   • message
     • sent using JNDI
   • MOM (Messaging server)
     • Message Oriented Middleware
       • can persist messages to avoid lost them (difference whe using WS)
       • reduce system bottleneck by using JMS provider (Multiple subscription using asyn)
     • JMS provider
       • which implements JMS specifications
     • options
       • ActiveMQ
       • Websphere MQ
       • Sonic MQ
       • Tibco MQ
     • Security
       • apacheMQ
         • allow to set users and roles
           • artemis-user.properties
           • artemis-roles.properties
           • broker.xml

3. 2 types of messages models

   • point to point
     • uses JMS provider to fullfill messaging rules
     • messages can be consumed once through a queue
     • synchronization
       • asyn
         • fire and forget (send message)
         • Should use MessageListener to catch and also resply a message
       • sync
         • request/reply messaging
           • can use a different queue to reply
     • Queue
       • expiryQueue
         • storage all the messages which has exceed its life time
       • can handle multiple queues
       • queueBrowser
         • allows us to get a snapshot of the queue content
       • can be dinamically created
   • publish / subscribe
     • uses topic to broadcast the message
       • topic is a virtual channel
     • durable subscriptions
       • mechanism that allow the consumer to get messages even is inactive, down etc
     • sharedConsumer
       • Allow us to define multiple consumers pointing to the same topic

4. versions

   • JMS 1.X
     • components
       • connection
       • session
       • message
       • message producer
       • message consumer
       • Destination
       • Connection Factory
     • configuration
       • add client dependency
         • artemis-jms-client-all
       • add JNDI properties file
         • must include 2
           • connection factory
           • initial factory
           • also the queue or topic details
     • communication types
       • P2P
         • steps
           • send message
             • create connection
             • session
             • lookup for destination
             • send and receive message
           • receive message
         • Queue browser
           • allow us to search a specific message
       • Publish/Subscription
         • need to create multiple consumers located in different hosts
         • need a consumer once the session is ready
   • JMS 2
     • components
       • JMSContext
         • handle by itself the creation of connection and session
       • JMS Producer
         • implements java.lang.Autocloseable interface(try block close this resource automatically)
         • provides methods to easyly handle headers, body and message in gral
       • JMSConsumer
         • implements java.lang.Autocloseable interface
         • provides methods to easyly handle headers, body and message in gral
     • new features
       • allow the injection of connection factory using the tag @JMSConnectionFactory
       • lookup can be achived by tag using as well
       • Allow to implement custum connection Factory using annotations or XML
     • message
       • structure
         • headers
           • metadata
           • 2 types
             • provider
             • developer
         • properties
           • 2 types
             • Application specific
             • provider specific
         • body/payload
           • contains data only
       • capabilities
         • set priority
           • through the producer
           • Higher priority, First out
           • default priority is 4
         • reply
           • using header "replyTo"
         • id
           • set an id in the header
         • setTimetoLive
       • types
         • Text
         • byte
         • object (can be serialized)
         • stream
         • map
       • Filtering
         • use selectors
           • can consider
             • properties
             • header
               • DeliveryMode
               • Priority
               • MessageID
               • CorrelationID
               • Type
           • uses the SQL syntanxis
       • Message Acknowledgements
         • confirmation from JMS SERVER to producer or consumer about msg delivered.
         • modes
           • auto ack
             • handle all the ack automatically
             • OOO Once and only once
           • dups
             • JMS Server
               • send the message more than once(can duplicate msg)
               • is not blocked (consumer should reply)
             • consumer
               • should be ready to handle duplicate msgs
               • the ack msg is automatically handled
             • be aware of performance
           • client
             • have to handle delivery acknowledgement (message.acknowledge() )
               • if not, the msg will stay in the queue until client send ack.
         • differents contract between producer WITH server AND server WITH consumer to ensure msg delivery
       • transaction
         • producer
           • can send multiple msg inside transactions
           • need to notify transactions are over, using commit()
         • consumer
           • receive multiple transaction
           • NEED TO confirm delivered transaction sending commit()
         • server
           • stores transactions inside cash whie wainting for commit()
         • enabled in the context

Images and files in the map