JRuby is a great way to use native Java libraries and get around the project overhead of Java, but how do you actually use Java from JRuby? This talk explores building a JRuby application, backed by the portable Java version of Couchbase Mobile. While JRuby is build to interface with Java, when calling out to JVM land there are all those little hurdles to overcome. Handling Strings correctly, using native Collection types, and interfacing with libraries which expect those native types instead of the ones provided by JRuby, and last but not least Implementing native interfaces to pass around. Oh and by the way all of this runs on a little Raspberry Pi!

1. JRuby,
a
Pi
and
a
Database

2. PHILIPP
FEHRE
Twi3er:
@ischi
Github:
@sideshowcoder
Developer
Advocate,
Couchbase

3. It’s
just
ruby!

7. NaEve
threads

8. 99%
vs
125%
|
17
sec
vs
11
sec
Yes
jruby
startup
Eme
is
slow
…

9. And
more
GC,
Java
Debugging
tools,
Java
Servers…

10. -­‐-­‐dev
tradeoff
performance
for
startup
@me

11. Lets
see
it
in
pracEce

12. Couchbase
Lite

13. Couchbase
Mobil
Couchbase
Lite
+
Sync
Gateway

14. Couchbase
Mobil
Couchbase
Lite
+
Sync
Gateway

15. Channels
Tags…

16. AuthenEcaEon
Facebook,
Mozilla
Persona,
User
+
Password,
OAuth

17. Sync
FuncEon

18. Channels

19. AuthenEcaEon

20. Why
JRuby?

23. NEED
TO
CALL
TO
JAVA
Java
has
loads
of
libraries
(like
Couchbase
Lite)
which
are
only
on
Java

24. Pi
on
Couch

27. Using
JRuby

28. Loading
JARs

29. Loading
naEve
JARs

30. Just
for
reference…
;)

31. Calling
Java
Methods

32. Calling
Java
Methods

33. CreaEng
Items
in
the
database

34. Some
Java
Idioms
in
Ruby

35. Naming

36. Se3er
and
Ge3er

37. Se3er
and
Ge3er

38. Se3er
and
Ge3er

39. Method
names

40. Anonymous
Classes

41. Java

42. Ruby
way
number
1

43. Ruby
way
number
2

44. GENERICS
They
don’t
auto
convert
types

48. Se[ng
up
sync

50. Querying
Couchbase
Lite

51. Querying
Couchbase
Lite

52. Querying
Couchbase
Lite

53. Querying
Couchbase
Lite

54. LOOKING
UNDER
THE
HOOD
How
JRuby
is
implemented

55. HACKING
JRUBY
CreaEng
a
method
from
Scratch

56. git
clone
h3ps://github.com/jruby/jruby
mvn
-­‐pBoostrap

57. Running
the
tests

58. 1.to_froscon
#
=>
“froscon”

59. Adding
to
RubyFixnum

60. Couchbase
Server
3.0
Beta
Bug
Bash
Download,
Find,
Report,
Win
• DOWNLOAD
Couchbase
Server
3.0
Beta
• Run
some
workload,
play
with
it,
FIND
a
bug
• If
you
find
a
bug,
REPORT
it!
­ All
bugs
count
–
anything
from
correctness,
to
performance,
to
usability,
to
docs
• WIN
Prizes!!
h`p://www.couchbase.com/bugbash
Contest
ends
Aug
31st
2014

61. QuesEons?

62. Links
• h3p://github.com/couchbaselabs/pi-­‐on-­‐couch
• h3p://www.couchbase.com/communiEes
• h3p://jruby.org