Grails Enterprise
Integration Strategies
Dave Klein
Contegix
Beyond Managed Hosting

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Use the coupon code “javaone” for a 30% discount
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Beta version available now at http://pragprog.com
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Birds of a Feather
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Grails [buzzword] [buzzword] Strategies
What do we mean by Enterprise Integration?
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Java Enterprise Edition
J
E E
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JEE JEE
JEE JEE JEE
JEE JEE
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Why Bother?
Why not leave well enough alone?
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Grails: More Than Just a Cool Framework
> Undeniable productivity gains
> Built on top of proven technologies
> Less code means less bugs
> Allows you to embrace change
> Reduce developer turnover (who would quit a Grails job?)
> Simple and painless deployment
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Itʼs a Really Cool
Framework!
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Integration Strategies
> Calling EJB Session Beans from a Grails App
• EJB 2
• EJB 3
> Accessing JNDI Resources from a Grails App
• Using JNDI Datasources
• Other JNDI Resources
> Legacy Databases
• GORM DSL
• Annotations
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Integration Strategies
> Calling Grails Actions from Non-Grails Apps
• From the server side using wget or curl
• From the client using AJAX
> Java Message Service
> Reuse Existing Spring Beans
> Reuse Existing Hibernate Entities
> What else?
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Calling an EJB 2 Session Bean From Grails
In app/grails-app/conf/spring/resources.groovy
beans = {
ejbJndi(org.springframework.jndi.JndiTemplate){
environment = [
"java.naming.factory.initial":"weblogic.jndi.WLInitialContextFactory",
"java.naming.provider.url" : "t3://some.enterprise.server:7001",
"java.naming.security.principal" : "dave",
"java.naming.security.credentials" : "1234"
]
}
empSession(org.springframework.ejb.access.
SimpleRemoteStatelessSessionProxyFactoryBean){
jndiName = "EmpSession"
businessInterface = "com.enterprise.some.ejb.session.EmpSession"
jndiTemplate = ref("ejbJndi")
}
}
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Calling an EJB 3 Session Bean From Grails
In app/grails-app/conf/spring/resources.groovy
beans = {
ejbJndi(org.springframework.jndi.JndiTemplate){
environment = [
"java.naming.factory.initial" : "weblogic.jndi.WLInitialContextFactory",
"java.naming.provider.url" : "t3://some.enterprise.server:7001"
"java.naming.security.principal" : "dave",
"java.naming.security.credentials" : "1234" ]
}
empSession(org.springframework.jndi.JndiObjectFactoryBean){
jndiName = "CoverageSession#org.foo.app.ejb.session.IEmpSessionRemote"
jndiTemplate = ref("ejbJndi")
}
}
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Integration Strategies
> Calling EJB Session Beans from Grails Services
• EJB 2
• EJB 3
> Accessing JNDI Resources from a Grails App
• Using JNDI Datasources
• Other JNDI Services
> Legacy Databases
• GORM DSL
• Annotations
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JNDI Datasources: Too Easy Not To Use
In app/grails-app/conf/DataSource.groovy
dataSource{
jndiName = “java:comp/env/jdbc/EnterpriseData”
}
Or in app/grails-app/conf/spring/resources.groovy
beans = {
dataSource(org.springframework.jndi.JndiObjectFactoryBean){
jndiName = “java:comp/env/jdbc/EnterpriseData”
}
}
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Other JNDI Resources
In app/grails-app/conf/spring/resources.groovy
beans = {
jndi(org.springframework.jndi.JndiTemplate){
environment = [
"java.naming.factory.initial" : "weblogic.jndi.WLInitialContextFactory",
"java.naming.provider.url" : "t3://some.enterprise.server:7001"
"java.naming.security.principal" : "dave",
"java.naming.security.credentials" : "1234" ]
}
}
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Integration Strategies
> Calling EJB Session Beans from a Grails App
• EJB 2
• EJB 3
> Accessing JNDI Resources from a Grails App
• Using JNDI Datasources
• Other JNDI Services
> Legacy Databases
• GORM DSL
• Annotations
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TABLE BK01
Column Name Date Type
ID_BK_PK NUMBER
BK_TITLE VARCHAR2(100)
BK_AUTHOR VARCHAR2(100)
BK_PGS NUMBER
ID_PUB_FK NUMBER
SEQUENCE ID_BK_PK_SEQ
class Book {
String title
String author
Integer pages
Publisher publisher
static belongsTo = Publisher
static mapping = {
table 'BK01'
columns{
id column: 'ID_BK_PK'
title column: 'BK_TITLE'
author column: 'BK_AUTHOR'
pages column: 'BK_PGS'
publisher column: 'ID_PUB_FK'
}
id generator: 'sequence', params:[sequence:'ID_BK_PK_SEQ']
}
}
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@
Or you can use annotations
(if you really want to)
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Brief Tangent on How to Sneak Introduce
Groovy and Grails Into The Enterprise
> Unit Testing
> Utility Scripts
> Internal Web Applications
> Prototypes
> JDBC -> GSQL
> XML Processing
> Itʼs easier to get forgiveness than permission
> Success Sells!
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Integration Strategies
> Calling Grails Actions from Non-Grails Apps
• From the server side using wget or curl
• From the client using AJAX
> Java Message Service
> Reuse Existing Spring Beans
> Reuse Existing Hibernate Entities
> What else?
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> Calling Grails Actions from Non-Grails Apps
> REST
• URL Mapping DSL
> SOAP
• Plugins for XFire, Axis, SpringWS and more
> Plain Old HTTP Call
> Execute process in Grails
> Return data - HTML, XML, JSON
• Grails Converters are awesome!
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Integration Strategies
> Calling Grails Actions from Non-Grails Apps
• From the server side using wget or curl
• From the client using AJAX
> Java Message Service
> Reuse Existing Spring Beans
> Reuse Existing Hibernate Entities
> What else?
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Dave Klein
dave.klein@contegix.com
Blog: dave-klein.blogspot.com
Twitter: daveklein