configure grails using spring

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Configure Grails for JMS and JTA using Spring

by Jonas Behmer


The question

Is it possible to use Grails for my new killer app that needs all the JEE-stack integration stuffwith distributed transactions on top of it?

YES OF COURSE!


• Philosophy

• Convention over configuration (sensible defaults)

• Dynamic and flexible

• Builds on existing technologies with a plethora of plugins

• Technology

• Groovy

• Dynamic programming for the JVM

• Spring

• Grails is a Spring MVC in disguise

• CoC is powered by dependency injection

• Hibernate

• Object to Relational db mapping

Grails in two minutes


Anatomy of a GrailsApp

Where configuration hides

Your domain will thrive hereTransactional components

The views

Write the tests and prosper


• We have more than one transactional resource (both JDBC and JMS)

• And we want JBoss to coordinate all the transactions for all of our transactional resources.

The scenario


Todo!Create a MessageListener

Create a container for the MessageListener

Add a lookup to a JBoss TransactionManager

Configure Hibernate

Deploy to JBoss


Setting up MessagingShopping list:

• Some kind of Message Listener Container that is JEE compatible

• A javax.jms.MessageListener

• A javax.jms.ConnectionFactory to create connections to the JMS provider

• Destination

• TransactionManager

Lots of options in Spring:SimpleMessageListenerContainer,DefaultMessageListenerContaineror a JCA-based MessageListener container.

Note!!!We could take a short cutand just install the JMS-Pluginfor Grails which uses as Default-MessageListenerContainer behindthe curtains.





Configure Hibernate

Deploy to JBoss


Setting up JTA for distributed transactions

• Spring handles transactions in Grails through a PlatformTransactionManager

• We need a JtaTransactionManager since we have both JMS and JDBC transactional resources

• The JtaTransactionManager can lookup the TransactionManager in JBoss through JNDI and delegate all the work!

By default we have a GrailsHibernateTransactionManager

The MessageListenerContainer we've setup will also use this TransactionManager


Spring PlatformTransactionManager

Class diagram of some the TransactionManager options offered by Spring

AbstractPlatformTransactionManager

HibernateTransactionManager

JtaTransactionManager

JpaTransactionManager

JmsTransactionManager

GrailsHibernateTransactionManager

PlatformTransactionManager





Configure Hibernate

Deploy to JBoss


• The last bit remaining is tying it all up in Hibernate

• Must know that we want to use transactions through JTA

• hibernate.transaction.factory_class = org.hibernate.transaction.JTATransactionFactory

• Must be made aware of the fact that JBoss coordinates the transactions:

• hibernate.transaction.manager_lookup_class = 'org.hibernate.transaction.JBossTransactionManagerLookup'

• Lookup a XA compliant datasource in Jboss through JNDI

Configure Hibernate





Configure Hibernate

Deploy to JBoss


• Clone my git repo

• git clone https://github.com/jonasbehmer/vehicleposition.git

• Buy the books

• The Definitive guide to Grails (2nd edition)

• Groovy in Action (2nd edition this summer)

• Mail a consultant

• [email protected]

Where to go from here?

configure grails using spring

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