Grails project lead Graeme Rocher delivers a deep dive into GORM, the object mapping technology used by Grails, which provides support for Hibernate (SQL), MongoDB and Neo4j amongst other implementations.

2. GORM Inside & Out

3. Graeme Rocher
Grails Project Lead
@graemerocher
rocherg@ociweb.com

4. Agenda
• GORM Introduction
• History of GORM
• GORM Source Code Tour
• Future of GORM

5. GORM Introduction
• Persistence layer used by Grails
• But, usable outside of Grails too
• Object mapping library with support for
SQL, MongoDB, Neo4j, Cassandra and
more
• http://gorm.grails.org

6. History of GORM

7. GORM 1.0
• Procedural meta-programming enhancement
for(domainClass in application.domainClasses) {
domainClass.metaClass.save = {->
sessionFactory
.currentSession.persist(this)
}
}

8. GORM 1.0
• Meta-programming presented problems
• Slower
• Harder to debug
• Harder to document

9. GORM 2.0
• Some procedural meta-programming enhancement
• ….and AST Transformations!!
domainClassNode.addMethod(
new MethodNode("save", PUBLIC, …)
)

10. GORM 3.0
• Only AST Transformations!!
• Bye bye runtime meta-programming….
domainClassNode.addMethod(
new MethodNode("save", PUBLIC, …)
)

11. GORM 2.0 / 3.0
• AST transformations were faster and
more performant, but
• Still harder to debug
• Still hard to document

12. GORM 5.0
• Only a few AST Transformations
• … and Traits!
trait GormEntity {
void save() {
datastore
.currentSession.save(this)
}
}

13. GORM 5.0
• Traits are:
• Easier debug
• Easier to document
• Fast
• @CompileStatic for the win!

14. GORM 5 - Hibernate
• Support for Hibernate 3, 4 and 5 (and
5.1)
• Completely rewritten and based on
traits
• Grails 2, Grails 3, Spring Boot or
Standalone

15. GORM 5 - MongoDB
• Rewritten for MongoDB 3.x driver
• Uses codecs to avoid Document to
Object conversion (much faster)
• Grails 2, Grails 3, Spring Boot or
Standalone

16. GORM 5 - Neo4j
• Rewritten for Neo4j 2.3.x
• Robust Cypher and Transaction support
• Embedded, REST & HA modes
supported
• Grails 2, Grails 3, Spring Boot or
Standalone

17. GORM Source Code
• https://github.com/grails/grails-data-
mapping
• Import with IntelliJ 16
• Build with Gradle

18. GORM SOURCE CODE TOUR

19. grails-datastore-core
• Core APIs applicable to all
• Object Mapping
• Dirty Checking
• Transaction Management
• Query API
• Configuration

20. grails-datastore-core
• Classes of Interest
• MappingContext
• PersistentEntity
• PersistentProperty
• ToOne
• ToMany
• Embedded

21. grails-datastore-core
• Classes of Interest
• Query
• Restrictions
• Projections
• Criteria
• BuildableCriteria

22. grails-datastore-gorm
• GORM Traits
• Public User Facing API
• Events
• Dynamic Finders
• Where Queries

23. grails-datastore-gorm
• Classes of Interest
• GormEntity
• GormStaticApi
• GormInstanceApi
• GormValidateable
• DynamicFinder

24. grails-datastore-gorm-tck
• Test compatibility kit
• Run for all implementations
• Hundreds of integration tests

25. grails-datastore-gorm-*
• -mongodb - GORM for MongoDB
• -hibernate - GORM for Hibenrate
• -neo4j - GORM for Neo4j
• -cassandra - GORM for Cassandra
• -test - GORM for
ConcurrentHashMap

26. Coming in GORM 6
• RxGORM
• MongoDB RX Support
• RxGORM REST Client
• Neo4j 3.x / Bolt Driver
• Native Multi Tenancy
3.0

27. RxGORM
• GORM for RxJava
• Reactive
• Stateless
• Non-Blocking
• Lightweight
3.0

28. DEMO - RxGORM

29. Q & A

30. Thank You!
Graeme Rocher
rocherg@ociweb.com
ociweb.com/grails

31. Come speak to the OCI Grails Team!
Web: grails.org
StackOverflow: http://stackoverflow.com/tags/grails
Slack: http://slack-signup.grails.org
Twitter: @grailsframework