This document provides an overview of messaging approaches in Java, specifically focusing on JMS and AMQP. It discusses the motivations for messaging, common messaging patterns like point-to-point and publish-subscribe, and compares RPC approaches. The document then dives into details of the JMS API and architecture, common implementations like ActiveMQ, and how Spring supports JMS. It also covers the AMQP protocol and model, implementations like RabbitMQ, and how Spring supports AMQP. Key books on these topics are recommended.

1. Messaging Approaches in Java
(JMS, AMQP)
Kirill Afanasjev
Jug.lv
Riga,Latvia

2. Why Messaging?
 1. Start sending binary data with TCP
 2. Add queueing
 3. Add networking abstraction
 4. Add authentification and ACL
 5. Add virtual connections
 6. Add high avalaibility
 7. Add publish/subscribe
 8. Result would be very similar :)

3. RPC
 CORBA, SOAP Web Services, RMI, XML-RPC
 Synchronous
 Tight coupling

4. Message oriented middleware
 Sender and receiver know nothing about each
other, only destination and message format
 Email is for people what messaging is for
applications

5. Advantages
 Asynchronous
A client does not have to request messages in
order to receive them
Sender can fire and forget the message to the
broker
 Reliable
It is possible to guarantee message is delivered
safely once and only once

6. Disadvantages
 Extra component in architecture (message
transfer agent or message broker)
 Inter-application communication tend to be
synchronous
 Lack of standarts

7. Point-to-point

8. Point-to-point
 Message queues, senders and receivers
 Message is sent to a queue
 Each message has only one consumer
 Queue may be configured to persist messages
 May be used for load balancing

9. Publish-subscribe

10. Publish-subscribe
 Publishers, subscribers, topics
 Message may have multiple consumers, or no
consumer at all
 Each message is delivered to every client
subscribed to a topic

11. JMS
 Java Message Oriented Middleware API
 Part of the Java EE
 Defined in specification developed under JSR
914
 RFC 6167 defines a jms: URI scheme
 JMS 1.0.2b (June 25, 2001)
 JMS 1.1 (March 18, 2002)
 JMS 2 - ?

12. JMS architecture
 JMS provider (example : ActiveMQ)
 JMS clients
 Messages
 Administered objects (Destinations and
connection factories)
 Native clients

13. JMS API
 ConnectionFactory
 Connection
 Session
 Message producer
 Message producer
 Destination
- Queue
- Topic
 Message

14. JMS API

15. JMS message
 Header
 Properties (optional)
 Body (optional)

16. JMS message headers
 JMSCorrelationId - (String) This header is set
by the application for use by other applications.
 JMSDestination
 JMSDeliveryMode - (Integer) This header is set
by the JMS provider and denotes the delivery
mode.
 JMSExpiration

17. JMS message headers
 JMSPriority - (Integer) The priority of the
message.
 JMSMessageId
 JMSTimestamp - (Long) The time the message
was sent.
 JMSReplyTo
 JMSType
 JMSRedelivered

18. JMS message delivery modes
 DeliveryMode.NON_PERSISTENT
 DeliveryMode.PERSISTENT

19. JMS message selector
 Message consumer receives only messages
whose headers and properties match the
selector
 A message selector cannot select messages
on the basis of content of the message body

20. JMS provider implementations
 Apache ActiveMQ
 Apache Qpid, using AMQP
 EMS from TIBCO
 OpenJMS, from The OpenJMS Group
 JBoss Messaging and HornetQ from JBoss
 Open Message Queue, from Sun Microsystems
 BEA Weblogic and Oracle AQ from Oracle
 RabbitMQ, using AMQP
 Solace JMS from Solace Systems
 SonicMQ from Progress Software
 StormMQ, using AMQP
 WebSphere MQ (formerly MQSeries) from IBM

21. Spring JMS support
 Message-driven POJOs
 MessageConverter, to convert between Java
objects and JMS messages
 JMSTemplate

22. Sending message with Spring
public class JmsQueueSender {
private JmsTemplate jmsTemplate;
private Queue queue;
public void simpleSend() {
this.jmsTemplate.send(this.queue, new MessageCreator(){
public Message createMessage(Session session) {
return session.createTextMessage("hello queue world");
}
});
}
}

23. Receiving message with Spring
public class ExampleListener implements MessageListener {
public void onMessage(Message message) {
if (message instanceof TextMessage) {
System.out.println(((TextMessage) message).getText());
}
}
}

24. Apache ActiveMQ
 Open source JMS 1.1 message broker
 Clustering
 Multiple message stores
 TCP, UDP, NIO, SSL, VM connectivity
 OpenWire API for high performance
 Stomp API for easier implementation
 REST API
 Can be used as in-memory JMS provider

25. Why AMQP, not JMS?
 Bound to Java
 Other protocols (STOMP, e.t.c) do not offer all
the functionality of the broker
 Single standart for interoperability of brokers
(AMQP is Protocol, not API)

26. Why JMS, not AMQP
 More implementations
 Better support in Java world
 Being an API allows for custom protocol
implementations (VM connector)

27. AMQP
 Open standart protocol
 Support in all major languages
 Binary wire protocol (JMS defines API only)
 1.0 version of protocol published 07 Oct 2011

28. AMQP protocol
 Defines how clients and brokers talk
 Data serialization, heartbeat
 Hidden inside client libraries

29. AMQP model
 Message broker - server
 User
 Connection – physical connection
 Channel – logical connection
 Exchanges – named entities, to which
messages are sent (may be durable or not)
 Queues – names entities, that store received
messages (may be exclusive)

30. AMQP model
 P - producer
 X - exchange
 C - consumer

31. AMQP model
 P/C – producer/consumer
 Ch – channel
 Conn – connection
 X - exchange

32. AMQP message
 Header + content body
 Immediate – message will be handled as
unroutable if there is no client waiting for it
 Expiration
 Priority
 Delivery mode

33. AMQP bindings
 Relationship between one queue and one
exchange
 Unconditional
 Conditional on fixed string
 Conditional on pattern match
 Conditional on content inspection
 Conditional on algorithmic comparison

34. Fanout exchange
 1:N message delivery pattern
 Bind a queue to the exchange and messages
sent to that exchange get delivered to all the
bound queues

35. Direct exchange
 Queue binds to exchange
with string key
 Publisher sends message
with key
 Message is passed to the
queue only if keys are equal

36. AMQP working group
 Bank of America, N.A.
 Barclays Bank PLC
 Cisco Systems, Inc.
 Credit Suisse
 Goldman Sachs
 JPMorgan Chase Bank & Co.
 Microsoft Corporation
 Novell
 Progress Software
 Red Hat, Inc.
 Software AG
 VMware, Inc.

37. AMQP in Java world
 Grails plug in
 Java client
 Scala / Lift support
 Spring AMQP project 1.0.0.RELEASE
(http://www.springsource.org/spring-amqp)

38. Spring AMQP project
 Similar to Spring JMS support
 AMQPTemplate
 MessageListener
 Transactions
 e.t.c

39. Apache QPID
 JMS interface for AMQP
 Message broker implemented in Java
 Version 0.12 :(

40. AMQP future
 ActiveMQ, HornetQ, e.t.c has plans to support
AMQP
 1.0 version?

41. RabbitMQ
 Leading implementation of AMQP
 Developed by SpringSource division of Vmware
 Full range of commercial support services
 Implemented in Erlang
 Clustering built-in

42. RabbitMQ performance
 We use it for login data processing
 Each user login in game = 1 message to the
queue
 Performance depends on
persistence/transactions enabled
 At 20k 1-kilobyte persistent messages per
second with sub-millisecond latency RabbitMQ
was far from being a bottleneck

43. Book to read
 Hohpe, Gregor; Bobby
Woolf (2003).
Enterprise Integration
Patterns: Designing,
Building, and Deploying
Messaging Solutions.
ISBN 0-321-20068-3.

44. Book to read
 ActiveMQ in Action
Bruce Snyder, Dejan
Bosanac and Rob
Davies
ISBN 1933988940

45. Book to read
 RabbitMQ in Action
Alvaro Videla and
Jason J.W. Williams
ISBN:
9781935182979

46. Questions?
 ?