![Welcome to SI Scala DSL
val messageFlow =
filter.using{p:String => p.equals("Cool World")} -->
transform.using{p:String => "Goodbye " + p} -->
handle.using{p:String => println(p)}
messageFlow.sendAndReceive[String]("Cool World")
Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 21](https://image.slidesharecdn.com/olegzhurakouskyspring-integration-scala-intro-120425102005-phpapp02/85/Oleg-zhurakousky-spring-integration-scala-intro-21-320.jpg)
![Welcome to SI Scala DSL
• Compile time validation vs initialization
validation and type safety:
filter.using{p:String => "Cool World"} - (filter can *only* return Boolean)
type mismatch; found : String => java.lang.String required: Function1[_, Boolean]
transform.using{p:String => println} - (transformer *must* return non-Unit value)
handle.using{p:String => println(p)} -->
handle.using{p:String => println(p)}
- value --> is not a member of o.s.i.d.SendingIntegrationComposition
(the first handler returns Unit (nothing of value in Messaging terms therefore the flow
can't continue)
Etc. . .
Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 22](https://image.slidesharecdn.com/olegzhurakouskyspring-integration-scala-intro-120425102005-phpapp02/85/Oleg-zhurakousky-spring-integration-scala-intro-22-320.jpg)
(Oleg zhurakousky)spring integration-scala-intro
- 1. Enterprise Integration Patterns using Scala and Spring Integration Oleg Zhurakousky SpringSource/VMware Twitter: z_oleg Email: ozhurakousky@vmware.com Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit
- 2. Enterprise Integration Patterns (EIP) Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 2
- 3. Messaging • Integration starts with Messaging Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 3
- 4. Why Messaging? • Logical Decoupling • Physical Decoupling – Producer and Consumer are not aware of one another • Easy to extend • Event-driven Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 4
- 5. Pipes and Filters – Endpoints (Filters) connected through – Channels (Pipes) exchanging – Message $> cat foo.txt | grep the | while read l; do echo $l ; done Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 5
- 6. Message • Payload can be any object • Header values are stored in a Map Headers Payload Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 6
- 7. Message Channel • Decouples Producers from Consumers • Provides extension point for interceptors • May be Point-to-Point • Or Publish/Subscribe Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 7
- 8. Message Endpoint • Producers send Messages to a Message Channel • Depending on their type, Message Channels may have Polling Consumers • Or Event-Driven Consumers Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 8
- 9. Message Endpoint Types • Transformer – Convert payload or modify headers • Filter – Discard messages based on boolean evaluation • Router – Determine next channel based on content • Splitter – Generate multiple messages from one • Aggregator – Assemble a single message from multiple Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 9
- 10. What is Spring Integration? • Framework is a reference implementation of Enterprise Integration Patterns • Built on top of Spring – Runs within any Spring ApplicationContext – All components are Spring-managed objects Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 10
- 11. The Big Picture Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 11
- 12. Spring Programming Model • Inversion of Control – Endpoints delegate to Spring-managed objects – Framework handles message reception and method invocation • Clean separation of Code and Configuration Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 12
- 13. Message Channel Types <channel id="sync-p2p"/> <channel id="async-p2p"> <dispatcher task-executor="someThreadPool" /> </channel> <channel id="async-buffering-p2p"> <queue capacity="50" /> </channel> <publish-subscribe-channel id="sync-pubsub" /> <publish-subscribe-channel id="async-pubsub" task-executor="someThreadPool" /> Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 13
- 14. Messaging Endpoints <int:gateway service-interface="foo.bar.MyGateway" default-request-channel="inChannel" /> <int:filter input-channel="inChannel" expression="payload.equals('World')" output-channel="transformingChannel" /> <channel id="transformingChannel"> <dispatcher task-executor="executor" /> </channel> <int:transformer input-channel="transformingChannel" expression="'Hello ' + payload" output-channel="loggingChannel" /> <int:service-activator input-channel="loggingChannel" expression="T(java.lang.System).out.println(payload)"/> Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 14
- 15. Channel Adapters and Messaging Gateways • JMS • HTTP (REST) • AMQP • RIA (Flex, AJAX) • TCP/UDP • WS (SOAP/POX) • File/Resource • Mail (POP3/IMAP/SMTP) • RMI • JDBC • RSS/ATOM • XMPP • FTP/FTPS/SFTP • Twitter • NoSQL(Mongo, • Spring Events Redis) • BPMN 2.0 (Activiti) Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 15
- 16. Tooling Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 16
- 17. Where does Scala fit in? Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit
- 18. Why Scala? • There are 2 types of people in this world – Like to say - "Don't like XML" – "Don't like XML" - but understand that its necessary evil. Appreciate alternatives but not overly concerned with the lack of. Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 18
- 19. Is XML or not to XML enough of an argument? Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit
- 20. Why Scala? (cont. . .) • True Type Safety vs IDE-Specific support • Typos and misconfiguration • Adding value based on the language features Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 20
- 21. Welcome to SI Scala DSL val messageFlow = filter.using{p:String => p.equals("Cool World")} --> transform.using{p:String => "Goodbye " + p} --> handle.using{p:String => println(p)} messageFlow.sendAndReceive[String]("Cool World") Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 21
- 22. Welcome to SI Scala DSL • Compile time validation vs initialization validation and type safety: filter.using{p:String => "Cool World"} - (filter can *only* return Boolean) type mismatch; found : String => java.lang.String required: Function1[_, Boolean] transform.using{p:String => println} - (transformer *must* return non-Unit value) handle.using{p:String => println(p)} --> handle.using{p:String => println(p)} - value --> is not a member of o.s.i.d.SendingIntegrationComposition (the first handler returns Unit (nothing of value in Messaging terms therefore the flow can't continue) Etc. . . Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 22
- 23. Relevant Info • Enterprise Integration Patterns - http://www.eaipatterns.com/ • Spring Integration project home - http://www.springsource.org/spring-integration • Spring Integration Scala DSL home - https://github.com/SpringSource/spring-integration-scala/wiki • Spring Integration Scala DSL blog - http://blog.springsource.org/2012/03/05/introducing-spring-integration- Copyright 2005-2010 SpringSource. Copying, publishing or distributing without express written permission is prohibit 23