Video and slides synchronized, mp3 and slide download available at http://bit.ly/XCw0Ka. Guilherme Silveira discusses the difficulties faced by an online educational platform and corresponding solutions implemented at Caelum, their curriculum - systems, languages and databases – and how everything works. Filmed at qconsf.com. Guilherme Silveira is Head Instructor at Caelum, a training and consulting company. He is the creator of Restfulie, Editorial Chief of InfoQ Brazil, technical editor for a Brazilian magazine, co-founder of the largest online Portuguese speaking Java user group. Currently writing and recording a Rest from Scratch series showing how to create REST systems using hypermedia. @guilhermecaelum

1. Introducing Online
Education to
Hypermedia
Guilherme Silveira
guilherme.silveira@caelum.com.br

2. Watch the video with slide
synchronization on InfoQ.com!
http://www.infoq.com/presentations
/Online-Education-Hypermedia
InfoQ.com: News & Community Site
• 750,000 unique visitors/month
• Published in 4 languages (English, Chinese, Japanese and Brazilian
Portuguese)
• Post content from our QCon conferences
• News 15-20 / week
• Articles 3-4 / week
• Presentations (videos) 12-15 / week
• Interviews 2-3 / week
• Books 1 / month

3. Presented at QCon San Francisco
www.qconsf.com
Purpose of QCon
- to empower software development by facilitating the spread of
knowledge and innovation
Strategy
- practitioner-driven conference designed for YOU: influencers of
change and innovation in your teams
- speakers and topics driving the evolution and innovation
- connecting and catalyzing the influencers and innovators
Highlights
- attended by more than 12,000 delegates since 2007
- held in 9 cities worldwide

4. who am I?

5. who am I?
• caelum.com.br founder

6. who am I?
• caelum.com.br founder
• training, content creation, development

7. who am I?
• caelum.com.br founder
• training, content creation, development
• since -50 years old working with education

8. who am I?
• caelum.com.br founder
• training, content creation, development
• since -50 years old working with education
• “arquitetura e design de software”

9. who am I?
• caelum.com.br founder
• training, content creation, development
• since -50 years old working with education
• “arquitetura e design de software”
• some work on rest

10. who am I?
• caelum.com.br founder
• training, content creation, development
• since -50 years old working with education
• “arquitetura e design de software”
• some work on rest
• brazil

11. what is Caelum?

12. what is Caelum?
• 3 cities, 100 employees

13. what is Caelum?
• 3 cities, 100 employees
• brick and mortar education

14. what is Caelum?
• 3 cities, 100 employees
• brick and mortar education
• java, ruby, agile development

15. what is Caelum?
• 3 cities, 100 employees
• brick and mortar education
• java, ruby, agile development
• user groups

16. what is Caelum?
• 3 cities, 100 employees
• brick and mortar education
• java, ruby, agile development
• user groups
• qcon brazil, conexao java, other events

17. what is Brazil?

18. who is this guy?

19. what is Brazil?

20. what is Brazil?
• brazil: 5565 cities

21. what is Brazil?
• brazil: 5565 cities
• largest são paulo: 11 million

22. what is Brazil?
• brazil: 5565 cities
• largest são paulo: 11 million
• 20th: 800 thousand

23. what is Brazil?
• brazil: 5565 cities
• largest são paulo: 11 million
• 20th: 800 thousand
• largest in a specific state: 296 thousand

24. what is Brazil?
• brazil: 5565 cities
• largest são paulo: 11 million
• 20th: 800 thousand
• largest in a specific state: 296 thousand
• fills 4 stadiums?

25. what is Brazil?
• brazil: 5565 cities
• largest são paulo: 11 million
• 20th: 800 thousand
• largest in a specific state: 296 thousand
• fills 4 stadiums?
• non well distributed developers

26. what is Caelum Online?

27. what is Caelum Online?
• brazil: 5565 cities

28. what is Caelum Online?
• brazil: 5565 cities
• thousands of coffee shops

29. what is Caelum Online?
• brazil: 5565 cities
• thousands of coffee shops
• outside brazil: 10 cities

30. what is Caelum Online?

31. what is Caelum Online?
• online learning

32. what is Caelum Online?
• online learning
• online teaching

33. what is Caelum Online?
• online learning
• online teaching
• online practicing

34. agenda

35. agenda
• problems that an online educational
platform faces

36. agenda
• problems that an online educational
platform faces
• examples

37. agenda
• problems that an online educational
platform faces
• examples
• existing systems, languages, databases

38. agenda
• problems that an online educational
platform faces
• examples
• existing systems, languages, databases
• how to connect everything

39. agenda
• problems that an online educational
platform faces
• examples
• existing systems, languages, databases
• how to connect everything
• really small services

40. traditional online
learning

41. traditional online
learning

42. traditional online
learning

43. traditional online
learning

44. traditional online
learning

45. machine learning
• + data
• + learning
• better results

46. collaborative filtering
• + data
• + learning
• better results

47. recommend movies
• amazon
• netflix
• ...

48. recommend daily news
• facebook
• twitter
• ...

49. recommend a friend?
• facebook
• twitter
• ...

50. recommend songs
• all those websites you know...

51. collaborative filtering

52. collaborative filtering
• recommend technologies that you should
study

53. collaborative filtering
• recommend technologies that you should
study
• recommend courses to attend

54. collaborative filtering
• recommend technologies that you should
study
• recommend courses to attend
• recommend jobs to take

55. collaborative filtering
• recommend technologies that you should
study
• recommend courses to attend
• recommend jobs to take
• recommend exercises to do

56. exercise difficulty

57. exercise difficulty
• MIT studies on CF and IRT

58. exercise difficulty
• MIT studies on CF and IRT
• CF is as good as IRT

59. exercise difficulty
• MIT studies on CF and IRT
• CF is as good as IRT
• our findings: we are not big data :(

60. exercise difficulty
• MIT studies on CF and IRT
• CF is as good as IRT
• our findings: we are not big data :(
• we can’t infer difficulty on multiple choice
so far

61. drop out rate
• can we detect them before they drop out?

62. how long for an
exercise?

63. how long for an
exercise?
students = []
students << [12, 150, 3, 15]
students << [4, 170, 32, 25]
students << [1, 10, 3, 25]
students << [12, 20, 31, 15]

64. finishes under 3
months?

65. finishes under 3
months?
labels = [1, 1, 0, 0]

66. finishes under 3
months?
students = []
students << [12, 150, 3, 15]
students << [4, 170, 32, 25]
students << [1, 10, 3, 25]
students << [12, 20, 31, 15]
labels = [1, 1, 0, 0]

67. trains

68. trains

69. trains

70. trains

71. what about guilherme?

72. what about guilherme?
guilherme = [6, 140, 25, 10]

73. what about guilherme?
guilherme = [6, 140, 25, 10]
model.predict(Node.features(guilherme))

74. guess!

75. SVM

76. SVM

77. fake data

78. fake data
labels = [1, 1, 0, 0]

79. fake data
students = []
students << [12, 150, 3, 15]
students << [4, 170, 32, 25]
students << [1, 10, 3, 25]
students << [12, 20, 31, 15]
labels = [1, 1, 0, 0]

80. real data

81. real data

82. real data
C TRAIN ACCURACY% ACCURACY%
0.08! 93.18%! 85.71%

83. SVM to classify (0,1, ...)

84. teacher and tutor
• multiple choice answers
• open answers
• code answer

85. multiple choice
• sucks?
• is the best/easiest to test ability

86. open answers
• great
• is the hardest to test ability
• any natural language processing experts?

87. code answers
• great
• is hard to test ability
• AST, auto correction, error margins

88. k-cluster
• another machine learning algorithm
• clustering

89. compare them...
• exercises
• students
• courses

90. and find...

91. and find...
• great exercises, not-so-great exercises

92. and find...
• great exercises, not-so-great exercises
• great students, not-so-great students

93. and find...
• great exercises, not-so-great exercises
• great students, not-so-great students
• great courses, not-so-great courses

94. common characteristics

95. common characteristics
height???

96. common characteristics
number of wrong answers
height???

97. common characteristics
number of wrong answers
height???
time spent

98. common characteristics
number of wrong answers
height???
time spent
number of exercises done

99. common characteristics
number of wrong answers
height???
time spent
number of exercises done
feedback given

100. common characteristics
number of wrong answers
height???
time spent
number of exercises done
feedback given
feedback rating

101. common characteristics
number of wrong answers
height???
time spent
number of exercises done
feedback given
feedback rating
likes

102. common characteristics
number of wrong answers
height???
time spent
number of exercises done
feedback given
feedback rating
likes
courses

103. common characteristics
number of wrong answers
height???
time spent
number of exercises done
feedback given
feedback rating
likes
courses
quantidade de caracteres

104. the 5D chart

105. they are here!

106. those are the groups

107. expected:
muitas perguntas, poucos erros,
muitos erros poucas perguntas
poucos erros,
poucas perguntas,
ajuda bastante

108. expected:
X
muitas perguntas, poucos erros,
muitos erros poucas perguntas
poucos erros,
poucas perguntas,
ajuda bastante

109. expected:
X X
muitas perguntas, poucos erros,
muitos erros poucas perguntas
poucos erros,
poucas perguntas,
ajuda bastante

110. expected:
X X
muitas perguntas, poucos erros,
muitos erros poucas perguntas
X
poucos erros,
poucas perguntas,
ajuda bastante

111. found:

112. found:
lots of questions,
less errors

113. found:
lots of questions, more errors,
less errors less questions

114. found:
lots of questions, more errors,
less errors less questions
more errors
less questions,
helped a lot

115. we have 5000
responsibilities

116. we have 5000
responsibilities
• data problems

117. we have 5000
responsibilities
• data problems
• user problems

118. we have 5000
responsibilities
• data problems
• user problems
• teacher problems

119. we have 5000
responsibilities
• data problems
• user problems
• teacher problems
• company problems

120. we have 5000
responsibilities

121. we have 5000
responsibilities
• we started with a small platform (mar2011)

122. we have 5000
responsibilities
• we started with a small platform (mar2011)
• we ended up with a huge payment, chat up
to certificate playform (oct2012)

123. single responsibility
principle

124. single responsibility
principle
• why not apply it to the system itself?

125. single responsibility
principle
• why not apply it to the system itself?
• + dependency injection

126. refactor, extract
===> exercise

127. refactor, extract
• constant
===> exercise

128. refactor, extract
• constant
• variable
===> exercise

129. refactor, extract
• constant
• variable
• method
===> exercise

130. refactor, extract
• constant
• variable
• method
• class
===> exercise

131. refactor, extract
• constant
• variable
• method
• class
• library
===> exercise

132. refactor, extract
• constant
• variable
• method
• class
• library
• project ===> exercise

133. mysql
caelum systems
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

134. data analysis
• http
• octave/ruby/java (mahout)
• octave/mysql/postgre/redis

135. answer analysis
• http
• ruby/java
• mysql/postgre/redis

136. badges/gamification
• http
• ruby
• postgre

137. payment
• http
• java
• mysql/postgre

138. exercises
• how to deal with new types of exercises?
• group
• simulations
• auto-correction

139. introducing hypermedia:
simply return an URI

140. training platform
external exercise

141. new external exercise attempt
training platform
external exercise

142. new external exercise attempt
training platform
external exercise
personal note: do not
draw splines again

143. new external exercise attempt
training platform your URI external exercise
personal note: do not
draw splines again

144. RPG activity
• http
• javascript
• 200 lines of code
• anyone can trash and rewrite in any language
(except perl?)

145. several autocorrectors
• ruby
• javascript
• sql

146. cloud partnership

147. cloud partnership
• do our training

148. cloud partnership
• do our training
• U$ 20 coupon

149. cloud partnership
• do our training
• U$ 20 coupon
• where do you write that code?

150. training platform
external exercise

151. new external exercise attempt
training platform
external exercise

152. new external exercise attempt
training platform your URI external exercise

153. coupon activity
• http
• ruby
• <100 lines of code

154. and then...

155. and then...
alunos
java + vraptor

156. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor

157. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
ondetrabalhar.com
ruby

158. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby

159. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
exercícios
RoR

160. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
exercícios
RoR
+ 1 projeto
scala + play

161. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
exercícios
RoR
+ 1 projeto
scala + play mountable engine
RoR

162. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
exercícios
RoR
+ 1 projeto
scala + play mountable engine + 1 ‘página’
RoR
js

163. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
analisador 1
sinatra
exercícios
RoR
+ 1 projeto
scala + play mountable engine + 1 ‘página’
RoR
js

164. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
pagamentos
java
analisador 1
sinatra
exercícios
RoR
+ 1 projeto
scala + play mountable engine + 1 ‘página’
RoR
js

165. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
pagamentos
java
analisador 1
sinatra
exercícios
RoR
+ 1 projeto
scala + play mountable engine + 1 ‘página’
RoR + 6 projetos js
RoR

166. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
pagamentos
java
analisador 1
sinatra
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
RoR + 6 projetos js
RoR

167. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
pagamentos
java
analisador 1
sinatra
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
RoR + 6 projetos js
RoR

168. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
casa do código pagamentos
java
java + RoR
analisador 1
sinatra
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
RoR + 6 projetos js
RoR

169. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
casa do código pagamentos
java
java + RoR
analisador 1
sinatra
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

170. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
casa do código pagamentos
java
java + RoR
interestie analisador 1
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

171. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
casa do código pagamentos
java
java + RoR
interestie analisador 1
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

172. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus
ondetrabalhar.com scala + vraptor
ruby
casa do código pagamentos
java
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

173. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
casa do código pagamentos
java
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

174. and then...
alumni.caelum.com.br
RoR alunos
java + vraptor
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
promo
casa do código pagamentos RoR
java
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

175. and then...
alumni.caelum.com.br métricas
RoR alunos java + octave
java + vraptor
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
promo
casa do código pagamentos RoR
java
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

176. and then...
alumni.caelum.com.br métricas
RoR alunos java + octave
java + vraptor
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
promo
casa do código pagamentos RoR
java
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

177. mysql
and then...
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
java + vraptor mysql
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
mysql promo
mysql
casa do código pagamentos RoR
java
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

178. mysql
and then...
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor mysql
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

179. mysql
and then...
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios
RoR analisador 2
+ 1 projeto java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
RoR RoR

180. mysql
and then...
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

181. mysql
and then...
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com java + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

182. mysql
did you see it?
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com java + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

183. mysql
did you see it?
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com java + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

184. mysql
october 2012
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
java + vraptor
solr mysql
gnarus sugest
ondetrabalhar.com scala + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

185. mysql
october 2012
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
redis
solr
roteiro vraptor
java + mysql
sugest
RoR gnarus
ondetrabalhar.com scala + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

186. mysql
october 2012
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
roteiro vraptor
java + chat redis
solr
RoR
mysql
gnarus sugest
???
ondetrabalhar.com scala + vraptor
java
ruby postgresql
mysql promo
mysql
casa do código pagamentos RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

187. mysql
october 2012
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
roteiro vraptor
java + chat redis
solr
RoR
mysql
gnarus sugest
???
ondetrabalhar.com scala + vraptor
java
ruby postgresql
mysql badges
promo
mysql
casa do código pagamentos ??? RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

188. mysql
october 2012
alumni.caelum.com.br mysql métricas
RoR alunos java + octave
roteiro vraptor
java + chat redis
solr
RoR
mysql
gnarus sugest
???
ondetrabalhar.com scala + vraptor
java
ruby postgresql
gráfica
mysql badges
promo
mysql
casa do código pagamentos
??? ??? RoR
java redis
java + RoR
postgresql interestie analisador 1
+ projetos sinatra + sequel
sinatra
sinatra + sequel
exercícios postgresql
RoR analisador 2
postgresql
+ 1 projeto postgresql java
scala + play mountable engine + 1 ‘página’
aws tickets RoR + 6 projetos js
postgresql
RoR RoR postgresql

189. what we did

190. what we did
• refactor, extract project

191. what we did
• refactor, extract project
• single responsibility micro projects

192. what we did
• refactor, extract project
• single responsibility micro projects
• dependency injection (dumb entry point
configuration)

193. 10s of projects

194. 10s of projects
• small teams (1-4 devs)

195. 10s of projects
• small teams (1-4 devs)
• lots of micro projects (1-20 classes)

196. 10s of projects
• small teams (1-4 devs)
• lots of micro projects (1-20 classes)
• 2 medium projects (20-200 classes)

197. 10s of projects
• small teams (1-4 devs)
• lots of micro projects (1-20 classes)
• 2 medium projects (20-200 classes)
• 1 big legacy project (500 classes) - bigger team

198. 10s of projects
• small teams (1-4 devs)
• lots of micro projects (1-20 classes)
• 2 medium projects (20-200 classes)
• 1 big legacy project (500 classes) - bigger team
• micro services

199. really small services

200. really small services
• small service, medium project

201. really small services
• small service, medium project
• micro teams

202. really small services
• small service, medium project
• micro teams
• if someone dies, the cost allows you to drop the
code, start again

203. really small services
• small service, medium project
• micro teams
• if someone dies, the cost allows you to drop the
code, start again
• protocol and communication is simple and stable

204. really small services
• small service, medium project
• micro teams
• if someone dies, the cost allows you to drop the
code, start again
• protocol and communication is simple and stable
• protocol and communication is simple and stable

205. really small services
• small service, medium project
• micro teams
• if someone dies, the cost allows you to drop the
code, start again
• protocol and communication is simple and stable
• protocol and communication is simple and stable
• protocol and communication is simple and stable

206. limitations
but are we not in the replicated era?

207. limitations
• protocol change ==> hell
but are we not in the replicated era?

208. limitations
• protocol change ==> hell
• client project needs user data ==> replicated data
but are we not in the replicated era?

209. limitations
• protocol change ==> hell
• client project needs user data ==> replicated data
• other problems that we have no idea
but are we not in the replicated era?

210. avoid
• multiple projects, same representation

211. enforcing
• small projects, specialized representations

212. communication
changes/evolution

213. communication
changes/evolution
• avoid

214. communication
changes/evolution
• avoid
• avoid

215. communication
changes/evolution
• avoid
• avoid
• avoid

216. communication
changes/evolution
• avoid
• avoid
• avoid
• avoid

217. communication
changes/evolution
• avoid
• avoid
• avoid
• avoid
• backward compatible

218. communication
changes/evolution
• avoid
• avoid
• avoid
• avoid
• backward compatible
• feel the pain

219. “How can I evolve my service since it’s going to
break compatibility?” - unknown SOA’er

220. “How can I evolve my service since it’s going to
break compatibility?” - unknown SOA’er
If it *breaks* compatibility you can not “not break
compatibility” - basic reasoning

221. “How can I evolve my service since it’s going to
break compatibility?” - unknown SOA’er
If it *breaks* compatibility you can not “not break
compatibility” - basic reasoning
How can I prepare myself for the future, where I
am 100% sure I will want to change something? -
the wise SOA’er

222. “How can I evolve my service since it’s going to
break compatibility?” - unknown SOA’er
If it *breaks* compatibility you can not “not break
compatibility” - basic reasoning
How can I prepare myself for the future, where I
am 100% sure I will want to change something? -
the wise SOA’er
“buy our product” - wise vendor

223. training platform
payments 3rd party provider

224. create payment
training platform
payments 3rd party provider

225. create payment
training platform
payments 3rd party provider

226. create payment
training platform
payments 3rd party provider
check status

227. create payment
training platform
payments 3rd party provider
check status
cancel order

228. create payment
training platform
payments 3rd party provider
cancel item check status
cancel order

229. create payment
training platform
payments 3rd party provider
cancel item check status
do A, B, C
cancel order

230. every new feature between the 2nd and 3rd
system means a protocol change between the 1st
and the 2nd

231. introducing hypermedia:
simply return an URI

232. training platform
payments 3rd party provider

233. create payment
training platform
payments 3rd party provider

234. create payment
training platform
payments 3rd party provider

235. create payment
training platform
payments 3rd party provider
your URI

236. create payment
training platform
payments 3rd party provider
your URI

237. changes to the 2nd system are not reflected on
the 1st anymore

238. what we are trying to do

239. what we are trying to do
• change the online learning experience, but how?
• KIS: keep it stupid, not simple
• micro teams, throw away if necessary
• protocol and communication are stupid and stable

240. what it allows

241. what it allows
• simple
• small stable communication
• unstable projects
• teams that come and go
• knowledge transfer
• freedom to try and trash

242. the end

243. Introducing Online
Education to
Hypermedia
Guilherme Silveira
guilherme.silveira@caelum.com.br