This document discusses experimenting with architecting web applications without using GWT-User. It recommends removing GWT-User from dependencies, avoiding JSNI and widgets in favor of JsInterop and Polymer, not using IDE plugins, and avoiding GWT RPC. It demonstrates this approach by developing WUnit, a unit testing framework for the game Warhammer. WUnit is implemented with a Java engine and model, and a frontend using GWT, Polymer, and JsInterop. This allows the code to be reused across platforms like web, Android, and iOS. The document discusses challenges encountered and open issues, and calls on the GWT steering committee to create more modular libraries to support this approach.

1. (ARCHITECTING WEB APPLICATIONS WITHOUT
GWT-USER)
Beyond GWT 3.0 Panic

2. Cristiano Costantini
@cristcost
+CristianoCostantini
http://lnkdin.me/p/cristianocostantini

3. GWT and ServiceMix project:
270K LoC, 5500 classes, more than 200 Maven modules

4. GWT MEET-UP 2015
“GWT 2.8 and Beyond”, by Ray Cromwell, Goktug Gokdogan

7. OK… WHAT DO WE
DO NOW?

9. STOP USING GWT?

10. No, I want to reuse Java in Web
Applications, mobile platforms and off-
course in the Java Backend
STOP USING GWT?

11. 1st. remove GWT-User from dependencies
2nd. don’t use JSNI, use JsInterop
3rd. don’t use Widgets, use Polymer
4th. don’t use IDE plugins*
5th. don’t use GWT RPC
Experiments Checklist:

12. 1st. remove GWT-User from dependencies
2nd. don’t use JSNI, use JsInterop
3rd. don’t use Widgets, use Polymer
4th. don’t use IDE plugins*
5th. don’t use GWT RPC
LET’S PUT IT INTO PRACTICE
Experiments Checklist:

13. INTRODUCING WUnit
an example application to test our
survival strategy

14. INTRODUCING WUNIT

15. WUNIT IS A UNIT TEST FRAMEWORK FOR…
INTRODUCING WUNIT

16. WUNIT IS A UNIT TEST FRAMEWORK FOR…
INTRODUCING WUNIT
…WARHAMMER, THE GAME

17. Testing which “Unit” is the best is really slow

18. Testing needs throwing a lot of dice

19. Using the “Assault
Dice” app…
…solves only
part of the problem

20. SO IT
CAME
WUnit

21. DEMO

22. MANUAL
DICE APP
WUNIT
0 12,5 25 37,5 50
BENCHMARK
(Minutes to test two units)

23. AT FIRST WUNIT IS BORN WITH THIS ARCHITECTURE
CONSOLE ENGINE MODEL
POJOJavaSystem.out

24. THE VALUE OF USING JAVA TO IMPLEMENT THE GAME LOGIC
ENGINE
Java
This code is so much complex
(Warhammer rules are so) that I wouldn’t
attempt to write it without a full OOP
language with solid development tools

25. THE VALUE OF USING JAVA TO IMPLEMENT THE GAME LOGIC
ENGINE
Java
This code is so much complex
(Warhammer rules are so) that I wouldn’t
attempt to write it without a full OOP
language with solid development tools

26. THE VALUE OF USING JAVA TO IMPLEMENT THE GAME LOGIC
ENGINE
Java
This code is so much complex
(Warhammer rules are so) that I wouldn’t
attempt to write it without a full OOP
language with solid development tools

27. THE VALUE OF USING JAVA TO IMPLEMENT THE GAME LOGIC
ENGINE
Java
This code is so much complex
(Warhammer rules are so) that I wouldn’t
attempt to write it without a full OOP
language with solid development tools

28. WUnit’s Engine is implemented in Java
Developed with strong TDD
(coverage is about 93.6%)
REUSE - REUSE - REUSE

29. AIM CROSS-PLATFORM
CONSOLE
ENGINE MODEL
POJOJava
System.out
WEB
ANDROID
GWT/j2cl
Android
iOS
j2objc

30. …AND THEN I WANTED TO TO BUILD
AN USER INTERFACE FOR WUNIT:
HOW DID I DID IT?
(Singular not available)

31. HOW TO USE GWT
AND NOT GWT-USER
(Experiments made with WUnit prototype)

32. ARCHITECTING WEB APPLICATIONS FOR REUSE
VIEW
INPUT
PRESENTER ENGINE MODEL
VIEW
OUTPUT
written with
POJO
written in (pure)
Java
written in
GWT/JS
written in
Polymer
Note: Engine and Model are compiled
to Javascript and run on the browser
thanks to javaemul !

33. REMOVE GWT-USER FROM DEPENDENCIES
1st

34. …but it comes the first failure!
JsInterop annotations and EntryPoint interface are inside GWT-user.
REMOVE GWT-USER FROM DEPENDENCIES
1st

35. …but it comes the first failure!
JsInterop annotations and EntryPoint interface are inside GWT-user.
Then, just avoid using anything else from GWT-user…
REMOVE GWT-USER FROM DEPENDENCIES
1st

36. …and avoid inheriting “User” module in your .gwt.xml

37. -- TO GWT STEERING COMMITTEE --
please create an independent library
with EntryPoint and JsInterop interfaces
so we can remove GWT-User from dependencies

38. Polymer is cool!
Write the widgets in javascript
DON'T USE WIDGETS, USE POLYMER
2nd

42. …displays as a table’s row on the browser
The custom HTML element…

43. <wunit-dice>element

44. <wunit-dice>element
Aspect

45. <wunit-game>element

46. <wunit-game>element
Aspect

47. @JsType
USE JsInterop
3rd

48. @JsType
USE JsInterop
3rd
* Note: this WUnit prototype has used the OLD JsInterop annotations

49. HTMLHOSTPAGE

50. LINK FROM GWT TO HOST PAGE

51. LINK FROM GWT TO HOST PAGE
Fail! I had to use JSNI (but it is limited to invoking query selector from Java,
and it can be rewritten with the new JsInterop)

52. OUTPUT
FROM JAVA TO POLYMER
ELEMENTS
VIEW
OUTPUT
Polymer

53. OUTPUT
FROM JAVA TO POLYMER
ELEMENTS
VIEW
OUTPUT
Polymer

54. INPUT
FROM POLYMER
ELEMENTS TO JAVA
Polymer
VIEW
INPUT

55. INPUT
FROM POLYMER
ELEMENTS TO JAVA
Polymer
VIEW
INPUT

56. DON'T USE IDE PLUGINS 4th

57. Unfortunately this solution does not works standalone…
I've hacked extensively the CodeServer
*

58. Unfortunately this solution does not works standalone…
I've hacked extensively the CodeServer
HACKS-HACKS-HACKS
*

59. <add-linker name="sso" />
FOCUS: SSO LINKER

60. <add-linker name="sso" />
FOCUS: SSO LINKER

61. -- TO GWT STEERING COMMITTEE --
please make Code Server more modular and reusable so we
can use it this approach without hacks

62. This problem is not solved yet
(WUnit don't uses client-server communication)
Work in progress
It would be possible to implement a clean approach if GWT was supporting GSON or
if the javaemul was supporting (a more rich subset of) Java Reflection
DON'T USE GWT RPC
5th

63. -- TO GWT STEERING COMMITTEE --
please create an independent and modular library
with the javaemul, so it can be extended in a clean way

64. CONCLUSIONS:

65. How much GWT-User have we used in WUnit?

66. How much GWT-User have we used in WUnit?
Instrument
for
coverage

67. How much GWT-User have we used in WUnit?
Compile,
including
gwt:compile

68. How much GWT-User have we used in WUnit?
Execute
JettyEmbeddedServer
(including Code Server)

69. How much GWT-User have we used in WUnit?
* Open and run the app
(to trigger Code Server compilation)

70. How much GWT-User have we used in WUnit?
Generate
coverage
report

71. COVERAGE REPORT WUNIT
(GWT Compilation and Code Server execution)

72. + SUPER SOURCES

73. + SUPER SOURCES

74. J2CL ?
FUTURE:

75. Maven archetype or Template for this approach
https://github.com/codejuicer/gwt-slimmize
(release after some clean up and official gwt 2.8.0)

76. Career Website:
https://www.thalesgroup.com/en/homepage/careers
Jobs info:
cv.risorseumane@thalesgroup.com
INTERESTED WORKING IN MY TEAM?

77. THANKS