13 - JMS. Asynchronous communication in Java - Michal Szynkiewicz - IT Event 2013 (5) This talk will give an introduction to Java Message Service. It will describe communication schemes supported by the JMS, give examples of JMS use cases, show how to use JMS with Spring Framework. It will mention key features incoming in JMS 2.0 and give a brief overview of some alternatives to JMS protocol. Michał Szynkiewicz http://itevent.if.ua/lecture/jms-asynchronous-communication-java

1. JMS
Asynchronous communication in Java
Michał Szynkiewicz
Examples: https://github.com/michalszynkiewicz/jms-examples
Email: michal.l.szynkiewicz@gmail.com

2. What's the point?
Why do we need asynchronicity?

4. @POST
public Response addCustomer(CustomerDto customer) {
validateCustomer(customer);
storeCustomer(customer);
return status(CREATED).build();
}

5. @POST
public Response addCustomer(CustomerDto customer) {
validateCustomer(customer);
storeCustomer(customer);
sendConfirmationLink(customer.getEmail());
return status(CREATED).build();
}

11. Solution: send email
asynchronously

12. + A standard
+ Multiple implementations
+ Loose coupling
-/+ intermediary server
- one way communication
- Java API
What's JMS

13. ● Queue
● Topic
Communication schemes

14. Queue

15. Usage in our case

16. Usage in our case

17. Usage in our case

18. ● Queue
● Topic
Communication schemes

19. Topic

20. When to use topic?

21. Topic use case: Error logging

22. Topic use case: Error logging

23. Topic use case: Error logging

24. Topic use case: Error logging

25. ●Headers:
● e.g. JMSCorrelationID, JMSPriority
●Properties
● application-specific headers
●Body
● e.g. a String, Map, Object
Message

26. ● Choosing a subset of all messages
● SQL-like syntax
● Can only use properties and headers
E.g. “JMSPriority = 6 and
myProperty='someValue'”
Message selectors

27. Message selectors

28. Reliability

29. Message acknowledgement
● Message are kept on server until message
acknowledgment comes
●Acknowledgement modes:
● AUTO — automatic
● CLIENT — manual (message.acknowledge())
● DUPS_OK — batch, may result in duplicates

30. ● Messages that failed to be processed, can be
redelivered
● Can be immediate or delayed
● After maximum number of redeliveries
message ends up in DLQ
Message redelivery

31. Message persistence
● When JMS server goes down — messages are
still kept
● May be disabled

32. Common issue: Request-response

33. On specJMS test it was able to handle 8M per
second.
It uses disk storage for persistence.
Source: http://planet.jboss.org/post/8_2_million_messages_second_with_specjms
How fast can it be?
On example of HornetQ

34. Available at github:
https://github.com/michalszynkiewicz/jms-examples
Spring code examples

35. Not much :)
● Simplified API
● Asynchronous sending (your code doesn't have
to wait for JMS provider)
● Delivery delay
What's new in JMS 2.0

36. ●AMQP
+ cross-platform, full-feature, widely used
- protocol still evolving, not backward compatible. Only
few providers implement current version.
●STOMP
+ via HTTP, widely implemented, lightweight
- protocol doesn't describe destination types, etc
●MQTT
+ extremely lightweight, used on mobile devices
- no queue (topic only), no message properties (only
headers)
(Some) other messaging standards

37. Questions?

38. Дякую
email:michal.l.szynkiewicz@gmail.com