The 2nd day of RubyKaigi 2010 (Afternoon)

In this afternoon, I attended these sessions:

• If the session has a movie in English, I just write summaries of the article. Please see that movies if you want more details.
• If the session has a movie in Japanese, I write the article with translating and little-summarizing.
• If the session has no movies in any languges, I try to write the article with little-summarizing.
• But, for Ceremonies and Lightning Talks, I only put the link of movies.
• And I don't translate Q&As in the article because these are the gift for attendees in there.

• Keynote (JRubyKaigi)
  Title: JRuby Pony Show
  • by Charles O.Nutter
  • by Tomas Enebo
  • The first idea for JRuby: [ruby-talk:13703] Ruby on a JVM - good or bad idea?
  • Jan Ame Peterson, the first developer of JRuby
  • Java One 2006 JRuby 0.9.0 rails runnning barely
  • Charles and Tom are hired to work full-time JRuby development by Sun
  • JavaOne 2007 JRuby 1.0
  • Normal Rails application run ok
  • 2008 Jan. JRuby 1.1 : Very Stable / Production OK
  • 2009 Aug. Chalres and Tom and NickSieger move to EngineYard
  • 2009 Oct. JRuby 1.4
  • 2009 Nov 1st JRubyConf
  • JRuby 1.5.2 in this week : 100% green Rails test runs
  • 4 demos
    • RUBOTO
      • JRuby on Android
      • Using ruboto-irb
      • Using ruboto-core
      • Using NexusOne presented by Tim Bray
      • Develop the irb suggestion for less key-typing because cell's key is quite small.
      • You can find ruboto-irb in Marlecplace
      • gem install ruboto-core
      • Build horizontal GUI and vertical GUI at once by writing DSL
      • Calling Tom's Android: 3 dollar for 1 minute because of under the international roaming, it's expensive demo :-)
    • Native C Extensions
      • Ruby SoC
      • C Extension wrapped by JNI
      • Available from JRuby 1.6
      • Manage the gem having Native C Extension from JMX
    • Win32OLE
      • Demo for operating IE8 on WindowsXP on MacOSX's VirtualBox
      • Compatible for Ruby 1.9 mode
    • Performance
      • Dynamic optimizations: -J-DJRuby.compile.dynopt=true
      • Available from JRuby 1.6
  • We continue porting C-only libs/exts to Java
  • Ad for our book : "Using JRuby"
    • Now writing 2 years, still in beta.
• Want to use Ruby from Java? RedBridge makes it pretty easy! (JRubyKaigi)
  • by Yoko Harada
  • I'm coming from Michigan
  • I was a specialist of Java Servlet in Japan at several years ago.
  • There are many cases using Java from JRuby.
  • I this theme: using JRuby from Java
  • This demo is my first rails application on GAE
  • I'm the commiter of pure-Java porting of nokogiri
  • JRuby is just Java application
  • Most valuable case for "Write Once Run Anywhere"
  • You can write one-liner with launching from jruby.jar
  • You can give JVM command options.
    • Giving bootclasspath argument improves performance of JRuby so much
  • You can est Java application using Cucumber via JRuby
  • RegBridge: A part of JRuby
    • embed-core
    • BSF on embed-core
    • JSR223 on embed-core
  • Why I create RedBridge despite JSR223 is already there?
    • The API of JSR223 is not friendly for Ruby
    • VariableType is Global
    • At that time, JSR223's license was not redistributable
  • RedBridge Demo
    • Spawn .rb program file from Java class
    • Load Ruby class from Java class
  • Run DataMapper from another JVM language(closure) Demo
  • More about embed-core, See the JRuby Wiki!
• Rubyist, it's time to develop your Rails app on Google App Engine (JRubyKaigi)
  • by Takeru SASAKI
  • What is GAE?
    • Google' cloud, PaaS
    • At 2008, Python available
    • At 2009, Java available
    • Scalable
    • Used in frontend of Google services
    • Datastore is BigTable
    • Mail environment is GMail
    • No need to consider server administration
  • In Java development
    • HTTP tier: Servlet
    • Datastore tier: JDO / JPA
    • cron tier, taskqueue tier and mail/xmpp tier: HTTP Handlers
  • Dashboard
    • Default UI that is good-enough and good-looking
    • fee free until 5 million page views per month
  • Things we cannot do
    • write native codes
    • multithread
    • socket
    • daemon
    • write to any filesystems
    • streaming
    • full ACID
  • Only handling simple KVS
  • How do we them on JRuby?
    • gem install google-appengine
    • dm-appengine
    • rails-appengine
    • rails-dm-appeigine
    • etc.
  • Applications what are working on Rack work also on GAE
    • Sinatra, Ramaze and so on
  • Datastore: It is one and only important matter
    • KVS
    • Entity: there are no schema
    • Query & index: manipulate many entities at once
    • EntityGroup : Automatic shareing by handling prefix of the entity
      • Same EntityGroup guarantees ACID fully
      • Another EntityGroups don't guarantees ACID
  • It's NOT compatible with ActiveRecord
    • TinyDS: ActiveRecord-looking library I develop
    • dm-appengine
    • Create your own library with low-level API by yourself
• Ruby API is Improved Unix API
  Movie(Japanese)
  • by Akira Tanaka
  • Ruby's IO APIs are almostly base on stdio from Ruby 1.4
  • These are relied on Unix and its atomosphere
  • So Ruby belongs to Unix atomosphere
  • Ruby is useful for Unix users
  • EOF
    • feof() : befavior of C : have read EOF already?
    • Ruby's eof? : behavior of Pascal : Will next be eof?
    • In fact, feof() is almostly not required, that is written in FAQ of C
    • In fact, There are not any EOF check methods in Python
    • From Ruby 1.9, we have stopped relying stdio in somewhere
    • So we don't implement any EOF flags
  • IO.select
    • Unix's select does not consider any inner buffers of stdio.
    • Ruby 1.8's IO.select had been implemented with considering inner buffers of stdio.
    • Ruby 1.9's IO.select implements original inner buffers instead of stdio.
  • read
    • For stdio, It is difficult to read what amount we need, like streaming.
    • We can do it by IO#sysread (behavior of Perl).
    • This Goes mostly.
    • But this is not considered about NIO because that stdio is not so.
    • Ruby 1.8's IO#sysread behaves diffrently in combination of [blocking, non-blocking] and [singlethread, multithread]
      • We hesitate to use it because we have to know what library is using backgroud thread at all.
      • This behavior is more worsen than Unix' one.
      • In Ruby 1.8, the combination using IO#sysread with method using inner buffers of stdio occures error: For instance, SSL Proxy on HTTP CONNECT
    • Use IO#readpartial
      • Blocking if non-blocking IO is used while data are empty
      • Able to combine with method using inner buffers of stdio
    • IO#read_nonblocking, IO#write_nonblocking
      • Non-blocking IO, and never block while data are empty
  • find -depth
    • Unix's find command includes 'depth' option
    • Ruby's find library does not have the feature corresponding 'depth' option
    • But, Unix's 'depth' option is also wrong because of not searching by depth
    • So we keep current find behavior and oppose to 'depth' feature as searching by depth
  • We will define PID as object
• Lightning talks
  
  Movie(Japanese) 01
  
  Movie(Japanese) 02
  
  Movie(Japanese) 03
  
  Movie(English) 04
  
  Movie(Japanese) 05
  
  Movie(Japanese) 06
  
  Movie(Japanese) 07
  
  Movie(English) 08
  
  Movie(Japanese) 09
  
  Movie(Japanese) 10
  
  Movie(Japanese) 11

N.B. These summaries may be imprecise.

I surprised that I can write one-liner with launching from jruby.jar:

$ java -jar /opt/local/share/java/jruby/lib/jruby.jar -e "puts 'Hello World'"
Hello World