The document discusses domain-driven design and object-relational mapping using Grails. It covers basic CRUD operations for a single domain class like Person and how those map to SQL commands and Grails URLs. It also discusses validation, dynamic finders, and integrating tests. Relationships between domain classes are covered through an example of a one-to-many relationship between a Person and Message domain class.

1. Groovy: Efficiency Oriented Programming
Lecture 11
Master Proteomics & Bioinformatics - University of Geneva
Alexandre Masselot - summer 2011

2. Agenda
‣ CRUD
‣ Integration tests
‣ Domain relationships
‣ Application configuration

4. One domain based app ↔ one database

5. One domain class ↔ one table

6. One domain bean ↔ one table entry

7. One bean operations: CRUD

8. One bean operations: CRUD
Action
Create
Read
Update
Delete

9. One bean operations: CRUD
Action
Create
Read
Update
Delete

10. One bean operations: CRUD
Action
Create
Read
Update
Delete

11. One bean operations: CRUD
Action
Create
Read
Update
Delete

12. One bean operations: CRUD
Action SQL Grails url
Create INSERT create
Read SELECT show
Update UPDATE update
Delete DELETE delete

13. One bean operations: CRUD
Action SQL Grails url
Create INSERT create
Read SELECT show
Update UPDATE update
Delete DELETE delete

14. One bean operations: CRUD
Action SQL Grails url
Create INSERT create
Read SELECT show
Update UPDATE update
Delete DELETE delete

15. Person joe = new Person(params)
➙ bean but no database entry creation

16. joe.save()
➙ insertion into table
(only if valid bean - constraints)

17. Validation
‣ Create only a valid bean
‣ 3 validation ways

18. Validation
‣ Create only a valid bean
‣ 3 validation ways
‣ Check explicitly for validation
joe.validate()

19. Validation
‣ Create only a valid bean
‣ 3 validation ways
‣ Check explicitly for validation
joe.validate()
‣ Save a catch exception
joe.save(failOnError:true)

20. Validation
‣ Create only a valid bean
‣ 3 validation ways
‣ Check explicitly for validation
joe.validate()
‣ Save a catch exception
joe.save(failOnError:true)
‣ Save a check for non-null return
assert joe.save()

21. Registered bean ⇔ joe.id != null

22. Reading a bean from the database

23. joe = Person.get(beanId)

24. Dynamic finders: retrieve from constraints

25. Dynamic finders (for single return)
‣ Domain class definition generate static methods
def p = Person.findByUsername(‘lucky_luke’)
def p = Person.findByFirstName(‘Lucky’)
def p = Person.findByFirstNameAndLastName(‘Joe’, ‘Dalton’)

26. Dynamic finders (for single return)
‣ Domain class definition generate static methods
def p = Person.findByUsername(‘lucky_luke’)
def p = Person.findByFirstName(‘Lucky’)
def p = Person.findByFirstNameAndLastName(‘Joe’, ‘Dalton’)
‣ Multiple results => returns first (sorted on id)
def p = Person.findByLastName(‘Dalton’)

27. Dynamic finders (for single return)
‣ Domain class definition generate static methods
def p = Person.findByUsername(‘lucky_luke’)
def p = Person.findByFirstName(‘Lucky’)
def p = Person.findByFirstNameAndLastName(‘Joe’, ‘Dalton’)
‣ Multiple results => returns first (sorted on id)
def p = Person.findByLastName(‘Dalton’)
‣ findByXxxx efficient with unique:true fields

28. Update
‣ Update: change fields values and save into database

29. Update
‣ Update: change fields values and save into database
1. modify bean as usual

30. Update
‣ Update: change fields values and save into database
1. modify bean as usual
2. validate/save as for creation

31. joe.delete() removes entry from table

32. Scaffolded controller hides CRUD operations

33. Explicit controller
‣ It is possible to generate scaffold controller code
generate-controller eop.lec11.twitter.Person

34. Explicit controller
‣ It is possible to generate scaffold controller code
generate-controller eop.lec11.twitter.Person
‣ PersonController.groovy write operation & test

35. Explicit controller
‣ It is possible to generate scaffold controller code
generate-controller eop.lec11.twitter.Person
‣ PersonController.groovy write operation & test
‣ For example, read:
def show = {
def personInstance = Person.get(params.id)
if (!personInstance) {
flash.message = "${message(code:
'default.not.found.message', .....)}"
redirect(action: "list")
}
else {
[personInstance: personInstance]
}
}

36. Time to go back to test!

37. Unit testing ↔ no dependency

38. Integration testing ↔ more complex biotope

39. Integration tests
‣ Resides under test/integration/
PersonIntegrationTests.groovy

40. Integration tests
‣ Resides under test/integration/
PersonIntegrationTests.groovy
‣ Launched with
test-app -integration

41. Integration tests
‣ Resides under test/integration/
PersonIntegrationTests.groovy
‣ Launched with
test-app -integration
‣ Results:
- summary on the console output (count success/failures)
- html files under target/tests-reports/html
- plain text files under target/tests-reports/html
- failure summary available
- stdout/stderr accessible for each test case

42. Faster grails command
‣ Launch command (<alt><ctrl>G) interactive

43. Faster grails command
‣ Launch command (<alt><ctrl>G) interactive
‣ On the console, enter command
test-app -integration

44. Faster grails command
‣ Launch command (<alt><ctrl>G) interactive
‣ On the console, enter command
test-app -integration
‣ Hit enter to relaunch last command

45. Faster grails command
‣ Launch command (<alt><ctrl>G) interactive
‣ On the console, enter command
test-app -integration
‣ Hit enter to relaunch last command
‣ After several commands, PermGenException can occur
- terminate
- relaunch interactive

46. Grails integration testing cons
‣ Slower to execute than unit

47. Grails integration testing cons
‣ Slower to execute than unit
‣ Test report is not integrated into eclipse

48. Grails integration testing cons
‣ Slower to execute than unit
‣ Test report is not integrated into eclipse
‣ Use only when unit test not possible

49. mockDomain: unit testing with domain class

50. mockDomain
‣ It is possible to make some unit testing with domain

51. mockDomain
‣ It is possible to make some unit testing with domain
‣ No real database is connected, but a fake layer

52. mockDomain
‣ It is possible to make some unit testing with domain
‣ No real database is connected, but a fake layer
‣ In each method (not setup())
mockDomain(Person)
mockDomain(Person, initialBeanList)

53. mockDomain
‣ It is possible to make some unit testing with domain
‣ No real database is connected, but a fake layer
‣ In each method (not setup())
mockDomain(Person)
mockDomain(Person, initialBeanList)
‣ All single domain CRUD (and more) operations possible

54. mockDomain example
void testDelete(){
//buildDaltonFamily() return a list of 4 Person
mockDomain(Person, buildDaltonFamily())
assert Person.count() == 4
Person p=Person.findByUsername('joe_dalton')
assertNotNull p
p.delete()
// we should only have 3 members left
assert Person.count() == 3
p=Person.findByUsername('joe_dalton')
assertNull p
}

55. mockDomain limits
‣ No explicit database operation (hibernate criteria, HQL) are
possible

56. mockDomain limits
‣ No explicit database operation (hibernate criteria, HQL) are
possible
‣ Multiple domain class interaction are fully possible (cf.
relationships)

57. mockDomain limits
‣ No explicit database operation (hibernate criteria, HQL) are
possible
‣ Multiple domain class interaction are fully possible (cf.
relationships)
‣ Connection with data already entered in a database

58. Hermit domain not very useful

59. Need for relationships
Twitter: Person ↔ Message

60. Message domain
create-domain-class Domain

61. Message domain
create-domain-class Domain
‣ Just a text (String) and a commiter (Person)
class Message {
String text
Person commiter
static constraints = {
text(size:1..140, blank:false)
commiter(nullable:false)
}
}

62. Message + Person
‣ Attach two messages to a user
Person joe=Person.findByUsername('joe_dalton')
new Message(text:'hello', commiter:joe).save()
new Message(text:'world', commiter:joe).save()

63. Message + Person
‣ Attach two messages to a user
Person joe=Person.findByUsername('joe_dalton')
new Message(text:'hello', commiter:joe).save()
new Message(text:'world', commiter:joe).save()
‣ Look for message from joe
Message.findAllByCommiter(joe)

64. Message + Person
‣ Attach two messages to a user
Person joe=Person.findByUsername('joe_dalton')
new Message(text:'hello', commiter:joe).save()
new Message(text:'world', commiter:joe).save()
‣ Look for message from joe
Message.findAllByCommiter(joe)
‣ Not possible to access to message directly from joe bean
- one solution: explicitly declare setCommiter(Person p) in
Message.groovy that would add the message to a list in joe;
- problem for deletion, save inconsistency...

65. Define a one-to-many relationship

66. One-to-many relationship
‣Message.groovy
//Person commiter
static belongsTo = [commiter:Person]

67. One-to-many relationship
‣Message.groovy
//Person commiter
static belongsTo = [commiter:Person]
‣Person.groovy
static hasMany = [messages: Message]

68. One-to-many relationship (cont’d)
‣ Add a message:
joe.addToMessages(new Message(text:‘hello world’)).save()

69. One-to-many relationship (cont’d)
‣ Add a message:
joe.addToMessages(new Message(text:‘hello world’)).save()
‣ Will execute the following actions
- create a message with joe as commiter
- save the message
- add the message to joe’s list

70. One-to-many relationship (cont’d)
‣ Access to the list
joe.messages

71. One-to-many relationship (cont’d)
‣ Access to the list
joe.messages
‣ Deleting will cascade
joe.delete()
- all messages with joe as commiter will also be deleted

72. Testing
‣ Test database consistency with two domain: integration testing
// taken from MessageIntegrationTests.groovy
// 4 Person are added in the setup() method
public void testListMessagesUserDeletion(){
Person joe=Person.findByUsername('joe_dalton')
Person averell=Person.findByUsername('averell_dalton')
joe.addToMessages(new Message(text:'hello world')).save()
joe.addToMessages(new Message(text:'i'm running')).save()
averell.addToMessages(new Message(text:'i'm eating')).save()
assert Message.count() == 3
assert Person.count() == 4
joe.delete()
assert Person.count() == 3
//having deleted joe should delete all message related to joe
assert Message.count() == 1
}

73. Back to the web: 2 scaffolded controllers