Slides from GR8Conf EU 2012: http://gr8conf.eu/Presentations/Grails-EE

1. Grails EE
Ivo Houbrechts
Ixor

2. About myself
▸ Ivo Houbrechts
▸ Belgium
▸ Grails user and plugin developer
▸ ivo.houbrechts@ixor.be
2

3. About Ixor
▸ Since 2002
▸ 40 experienced ICT professionals
▸ Software development for the JVM
▸ Consultancy and product development
▸ Loyal customers in Finance, Telecom and
Government
3

4. Agenda
▸ Grails as part of Java EE
▸ Enterprise telco app
▸ Development environment
▸ Development productivity
▸ Plugins
▸ Conclusions
4

5. Agenda
▸ Enterprise telco app
▸ Development environment
▸ Development productivity
▸ Plugins
▸ Conclusions
4

6. Enterprise application
5

7. The application
▸ Order intake and customer care
– used by call center and dealers
– 1000 users
▸ 75 tailored screens
– complex compositions
6

8. Deployment
▸ ESB backend
– SOAP web services
– no direct database access
– domain defined in XSD’s
– Spring / JAXB (code generation)
▸ Weblogic 10 cluster
7

9. Development environment
8

10. To Grails or not to Grails
▸ Spring MVC + Freemarker
– no components
– (almost) no IDE support
▸ project behind schedule
➭ speed up with Grails
9

11. To Grails or not to Grails
▸ Spring MVC + Freemarker
– no components
– (almost) no IDE support
?
▸ project behind schedule
➭ speed up with Grails
9

12. Build
▸ Multi module Maven project
–Command line Grails
• Mix Ivy and maven dependency resolution
• CI agents need both Maven and Grails
• Improved maven support in Grails 2.1
–9 modules
• JAXB / WS
• AST
• Grails inline plugins
• Grails war, ear, config resources
10

13. Development team
▸ 2 scrum teams, 14 developers
▸ Groovy / Grails experience is rare
▸ Learning curve
– 2 weeks self study
– dynamic language
– Intellij IDEA
▸ Vast majority enthusiastic
11

14. Development productivity
12

15. Modularization
▸ (inline) plugin system
▸ plugins are standalone apps
– views, web.xml, bootstrap, spring beans, url mappings...
▸ reuse across applications
▸ plugin compilation time
– Grails 2 binary plugins
13

16. AST transformations
▸ Compiler plugin
▸ Rather complex
▸ Only for framework developers?
14

17. AST transformations
▸ Compiler plugin
▸ Rather complex
14

18. AST example 1
BillingType getBillingType() {
return data.customer.customerBillingInfo.customerBillType
}
void setBillingType(BillingType billingType) {
data.customer.customerBillingInfo.customerBillType =
billingType.data
}
15

19. AST example 1
BillingType getBillingType() {
return data.customer.customerBillingInfo.customerBillType
}
void setBillingType(BillingType billingType) {
data.customer.customerBillingInfo.customerBillType =
billingType.data
}
@PropertyDelegate('customer.customerBillingInfo.customerBillType')
BillingType billingType
15

20. AST example 2
private productOffering
ProductOffering getProductOffering() {
if (!productOffering) {
productOffering = ProductCatalog.get(ProductOffering,
data.typeInfo.productOfferingId)
}
return productOffering
}
16

21. AST example 2
private productOffering
ProductOffering getProductOffering() {
if (!productOffering) {
productOffering = ProductCatalog.get(ProductOffering,
data.typeInfo.productOfferingId)
}
return productOffering
}
@ProductCatalog('typeInfo.productOfferingId')
ProductOffering productOffering
16

22. AST example 3
List<ContactInfo> getContactInfoList() {
List<ContactInfo> result = []
for (contactInfo in data.customer.contactInfoList.contactInfo) {
result << contactInfo.createNewWrapperInstance()
}
return result
}
void clearContactInfoList() {
data.customer.contactInfoList.contactInfo.clear()
}
void addToContactInfoList(ContactInfo contactInfo) {
data.customer.contactInfoList.contactInfo << contactInfo.data
}
void addAllToContactInfoList(List<ContactInfo> contactInfoList) {
for (contactInfo in contactInfoList) {
addToContactInfoList(contactInfo)
}
}
void removeFromContactInfoList(ContactInfo contactInfo) {
data.customer.contactInfoList.contactInfo.remove(contactInfo.data)
}
17

23. AST example 3
List<ContactInfo> getContactInfoList() {
List<ContactInfo> result = []
for (contactInfo in data.customer.contactInfoList.contactInfo) {
result << contactInfo.createNewWrapperInstance()
}
return result
}
void clearContactInfoList() {
data.customer.contactInfoList.contactInfo.clear()
}
void addToContactInfoList(ContactInfo contactInfo) {
data.customer.contactInfoList.contactInfo << contactInfo.data
}
void addAllToContactInfoList(List<ContactInfo> contactInfoList) {
for (contactInfo in contactInfoList) {
addToContactInfoList(contactInfo)
}
}
void removeFromContactInfoList(ContactInfo contactInfo) {
data.customer.contactInfoList.contactInfo.remove(contactInfo.data)
}
@PropertyDelegate('customer.contactInfoList.contactInfo')
List<ContactInfo> contactInfoList
17

24. AST summary
▸ AST transformation code: 800 lines
– Java
– Groovy in separate module
▸ But:
– 200+ domain classes
– 1000+ usages
– ~10K lines omitted
– improved readability!
18

25. UI components
▸ Version 1
– 12 screens
– html tags in GSPs
– Example: first name edit field
19

26. UI components 2.0
▸ Version 2
20

27. UI components 2.0
▸ Version 2
20

28. UI components
▸ Html in GSPs becomes problematic
– huge GSPs
– virtual impossible to change look and feel
– inconsistent development
➭ custom tags / components with documented
API
21

29. UI components
22

30. UI components
22

31. UI components
▸ Reusable Grails plugin with kitchen sink
▸ 65 components
– Form row
– Input
– Layout (section, box, buttons, links ...)
– Ajax
– Behavior (autocomplete, menu, toggle ...)
23

32. UI components
▸ Grails tag
– documented component API, code completion
– ideal for logic
– not suited for markup:
def box = { attrs, body ->
out << “<div class=”box $clazz>”<div class=”boxHeader”>”
out << attrs.header << “</div><div class=”boxBody”>”
out << body()
out << “<div>”
}
24

33. UI components
▸ tmpl namespace
– markup in GSP
– simple to use
– no documented API, no code completion, etc.
▸ render template from tag
– markup in GSP
– documented API, code completion, etc.
– maintenance hell
25

34. UI components
▸ GSP taglib plugin
– simple to use
– documented API, code completion, etc.
– tags in taglib directory
– generated xxxTagLib.groovy
26

35. UI components
▸ GSP taglib plugin
– simple to use
– documented API, code completion, etc.
– tags in taglib directory
– generated xxxTagLib.groovy
26

36. Plugins
27

37. Rich domain validation
▸ Validation for non-Grails domain classes
– web services
– deep nested objects
– limited build-in support
▸ Extended validation
– cascaded validation
– partial validation
– constraint groups
– instance validation
28

38. Rich domain validation
class OrderItem {
... ▸ Validation for non-Grails domain classes
static web services = {
– constraints
– deep nested objects
//instance constraint
– limited build-in support
forbiddenAtLineLevel(validator: {
...
}) Extended validation
▸
– cascaded validation
//constraint group
– partial validation
characteristicsOnly {
– constraint groups
characteristics(cascade: true)
instance validation
–childOrderItems(cascade:
[excludes:'forbiddenAtLineLevel']])
}
}
}
orderItem.validate(groups: [“characteristicsOnly”],
includes: [“*.delivery”],
28 excludes: [...])

39. 29

40. order.validate(groups: [“deliveryInformation”])
29

41. Rich domain DI
▸ DI for non-Grails domain classes
– @Inject, @Resource
– auto wiring at object initialization and de-serialization
– move logic from controllers to domain classes
▸ see http://livesnippets.cloudfoundry.com
@RichDomain
class Customer {
@Inject
transient CustomerWebService customerWebService
...
}
30

42. Geb
▸ In-browser functional tests
▸ Maintainable tests
– Pages / Modules
▸ Test javascript and (partial) css
– Ajax timing issues
31

43. Webflow
▸ Indispensable for
– wizards
– page flows
▸ see http://livesnippets.cloudfoundry.com
32

44. Resources
▸ Organize javascript and css
– jawr
– less css
▸ Grails 2.0 : resources plugin
33

45. Conclusions
34

46. Developer experience
▸ Frustrations
– Build
– debugger
– Runtime vs compile time errors
– Grails upgrades
▸ Satisfaction
– Groovy power
– Convention over configuration
– Fun
▸ Generally enthusiastic
35

47. Developer experience
▸ Frustrations
– Build
– debugger
– Runtime vs compile time errors
– Grails upgrades
▸ Satisfaction
– Groovy power
– Convention over configuration
– Fun
▸ Generally enthusiastic
35

48. Development cost
▸ Fast kickoff with Grails
– GORM
– Scaffolding
▸ Short term development cost
– Determined by domain complexity
– Technology is minor factor
▸ Long term benefits
– Code size
– Code readability
36

49. Development cost
▸ Fast kickoff with Grails
– GORM
– Scaffolding
▸ Short term development cost
– Determined by domain complexity
– Technology is minor factor
▸ Long term benefits
– Code size
– Code readability
36

50. Development cost
▸ Fast kickoff with Grails
– GORM
– Scaffolding
▸ Short term development cost
– Determined by domain complexity
– Technology is minor factor
▸ Long term benefits
– Code size
– Code readability
36

51. Development cost
▸ Fast kickoff with Grails
– GORM
– Scaffolding
▸ Short term development cost
– Determined by domain complexity
– Technology is minor factor
▸ Long term benefits
– Code size
– Code readability
36

53. ?
38