here’s a little plugin for ActiveRecord-JDBC which enables simple use of MySQL master-slave configurations

active-record-jdbc-mysql-master-slave

A java programmer, a scala dev and a ruby guy meet on #irc. Says the java guy to the… wait, this is not the beginning of a joke.

jan: Map<String,Map<String,String>>  argggghh
thepete: mmm, readable code, yummy
David: Map<String, Map<String, String>> is perfectly reasonable. :)
       The real problem is that Java makes you declare it twice.
jan: Map<String, Map<String, Object>> m =
       new HashMap<String, Map<String, Object>>();
mccraig: stop that !
mccraig: my eyez
David: val m = new HashMap[String, Map[String, Object]]
thepete: ze goggles;
David: or val m = ne wHashMap[(String, String), Object] if you prefer. :)
jan: what type will m have? Map?
David: val m : Map[(String, String), Object] = new HashMap
mccraig: m = {}
David: m["1"] = "stuff"; m[1] # Why is this returning nil??? :(
mccraig: yeah i know, but whatever
jan: MapWithIndifferentAccess
mccraig: my eyez hurt less
David: my eyez weep
mccraig: u can get eyedrops for that
David: You can get gogglez. :-)
jan: can i blog this? :)

Ok, another fail post, this time regarding java.

Remember, Java has only signed types (int, byte, short, long) - char is the only exception.

WTF?

James Gosling says (source):

Quiz any C developer about unsigned, and pretty soon you discover that almost no C developers actually understand what goes on with unsigned, what unsigned arithmetic is.
Things like that made C complex. The language part of Java is, I think, pretty simple.

Ok, so he is basically saying that J. Random Developer is too stupid to care about differences in signedness, and decided to make them all signed, maybe for consistency reasons or who knows. Sometimes you don’t care about signed variables. Say for example you’re dealing with any sort of  decoding/encoding problems (like network protocols). Now you have to make sure that you don’t trip over sign problems (esp. with implicit casts). Here’s a snippet from the JRuby codebase (base64 decoding routines):

   private static byte safeGet(ByteBuffer encode) {
     return encode.hasRemaining() ? encode.get() : 0;
   }
   ...
   int s = safeGet(encode);
   while (((a = b64_xtable[s]) == -1) && encode.hasRemaining()) {
      // do something
   }

In Java, a byte can have a value from -128 to 127. This code above works fine, except when you feed it data which is not just in the range of displayable ascii characters, because the variable “s” will then potentially be negative and cause an ArrayOutOfBoundsException. So the general recommendation is to use the next bigger signed type (short instead of byte, long instead of int). If you’re using someone else’s API (java.nio.ByteBuffer in this case) you don’t have the choice and therefore you have to be extra careful when using it. In this case the right thing to do is a bitwise AND with 0xFF to strip the signed part of the int.

  while (((a = b64_xtable[s & 0xff]) == -1) && encode.hasRemaining()) { // do something }

Here’s the JRuby bug report and a general introduction to java sign issues by Sean R. Owens.

No big changes this time, mainly compatibility fixes for JRuby 1.0. It is now also possible to build the project using Maven, for those too afraid to use rake. Documentation and code for springy are available here.

I’m also happy to announce that Craig Walls, the author of “Spring in Action”, is going to talk about Springy as part of his “Spring Cleaning: Tips for Managing XML Clutter” talk at this year’s No Fluff Just Stuff series of events as well as the Spring Experience 2007 in Florida.

While trying to create a unified testing framework (shared between Rails and our Java backend code) I came across ActiveRecordJDBC which is an adapter to use JDBC drivers with JRuby on Rails. It works fine, although it can be a bit complicated to get a DRY database.yml configuration. The goal is to get rid of our dbunit/manually crafted database tests on the Java side by using ActiveRecord fixtures. After some research I found out about the Rails integration project (now called GoldSpike), which tries to make it easy to deploy a Rails app on a Java servlet container such as jetty. As far as I know Thoughtworks uses this approach to deploy their new product, Mingle. GoldSpike is under constant development but it is already usable, although a few patches were required. After everything was set up, a simple

$ rake war:standalone:create
Reading user configuration
Assembling web application
Adding Java library commons-pool-1.3
Adding Java library rails-integration-1.1.1
Adding Java library activation-1.1
Adding Java library mysql-connector-java-5.0.5
Adding Java library bcprov-jdk14-124
Adding Java library jruby-complete-1.0
Adding web application
Adding Ruby gem ActiveRecord-JDBC version 0.4
Creating web archive

creates a .war file which can be directly deployed to a container. I’ve never been a big fan of war files, but in the context of JRuby+Rails it makes perfect sense, because Ruby and all the required gems can be packaged up in a single file. No need to worry about missing gems, C bindings or wrong versions of the installed software, all you need to deploy is Java and jetty (which is pretty lightweight).

Not quite sure what the implications of this are, but it seems like a good alternative to mongrel/CRuby deployments. Performance-wise it looks good, too, though we haven’t done any benchmarking. GoldSpike doesn’t have a project homepage yet, but you can find it on the jruby-extras project page. Let’s wait and see what this will mean for the adoption of Rails in corporate environments (Oracle is currently looking for Rails developers to join the Enterprise 2.0 team, for example).

We’ve just got ourselves a couple of new servers for running SONAR on, for internal use and demonstration. They are quite beefy, with 8GB RAM, 15k disks, and 8 x 3.2GHz threads. We decided to go with centos 5 as the operating system, since we have had pain installing Oracle on our debian platforms. Here is the install procedure I uncovered, which gets the server ready for SONAR on either MySQL or oracle. It covers installing Ruby, RubyGems, lots of useful Gems, Java, and Oracle 10g

yum install -y ruby
yum install -y ruby-devel ruby-docs ruby-ri ruby-irb ruby-devel ruby-rdoc
yum install -y w3m # for text based browsing and downloading, where curl won't work

# download rubygems from rubygems.org with w3m then...
gunzip rubygems-0.9.4.tgz
tar xf rubygems-0.9.4.tar
cd rubygems-0.9.4
ruby setup.rb

# get jdk rpm from java.sun.com and install

# add an /etc/profile.d/java.sh file, containing
##
JAVA_HOME=/usr/java/default
export JAVA_HOME
##
chmod +x /etc/profile.d/java.sh
source /etc/profile.d/java.sh

yum install -y ImageMagick-devel
yum install -y perl-DBI
yum remove -y sendmail
yum install -y postfix
chkconfig postfix on
yum install -y ntp
chkconfig ntpd on
yum install -y mysql-server mysql mysql-devel

chkconfig mysqld on
/usr/bin/mysqladmin -u root password '<password>'
/usr/bin/mysqladmin -u root -h <hostname> password '<password>'

yum install -y gcc
gem install builder
gem install camping
gem install capistrano
gem install cgi_multipart_eof_fix
gem install cheat
gem install chronic
gem install ci_reporter
gem install daemons
gem install fastthread
gem install gem_plugin
gem install hpricot
gem install image_science
gem install jerbil --source http://code.trampolinesystems.com
gem install json
gem install markaby
gem install metaid
gem install mongrel
gem install needle
gem install net-sftp
gem install net-ssh
gem install rake
gem install rmagick  # [ ignore errors about fonts... they are just for the docs ]
yum install -y libxml2-devel
yum install -y libxslt-devel
gem install ruby-xslt
gem install rubyforge
gem install RubyInline
gem install mysql -- --build-flags --with-mysql-config
yum install -y httpd
yum install -y subversion

# install rpmforge for centos 5 as detailed here :
# http://wiki.centos.org/Repositories/RPMForge#head-d766e7aacdee6150c6705d9369aa36c9bcabc139

yum install -y firefox
yum install -y xorg-x11-xauth
yum install -y vnc-server
yum install -y emacs
yum install -y libXtst
yum install -y xorg-x11-utils
yum install -y xorg-x11-resutils
yum install -y xorg-x11-server-utils

yum install -y compat-libgcc-296 compat-libstdc++-296 compat-libstdc++-33 openmotif22
yum groupinstall -y "Development Libraries"
yum groupinstall -y "Development Tools"
yum groupinstall -y "Legacy Software Development"
yum groupinstall -y "Server Configuration Tools"
yum groupinstall -y "X Software Development"
yum groupinstall -y "Administration Tools"

# fire up a vncserver on the remote machine :
vncserver
# and enable connections to the X server from other accounts :
xhost +

# connect an ssh session from your local machine, forwarding the vnc port [ 5900 + screen # ]
# connect your local vnc client to the server
# run firefox on the server
# download oracle 10g from www.oracle.com, thus avoiding having to upload 750M at 512Kb/s
# install as shown here : http://www.dizwell.com/prod/node/681?page=0%2C3
# and add an init.d startup script as described here : http://www.dizwell.com/prod/node/50?page=0%2C4

# done ! reboot to check that your init.d scripts are functioning correctly

I’ve just released a new version of springy, the JRuby-based alternative to Spring’s XML configuration format. It now has a “serialise-to-xml”-feature which allows you to write your whole config to a nicely formatted Spring XML file. Why would you want to do that ? In our case we’ve created a Ruby-based configuration framework modeled after Rails environments which pulls config files from different locations, deals with overrides and so on. The only downside is that this is pretty slow (especially when unit testing), hence the idea of serialising the whole context to XML.

The serialised XML config file is about twice the size of the springy context (~1600 vs. ~800 lines), which shows how expressive Ruby can be. A small example from our configuration:

DAOS = [ :ZoneDAO, :EmailDomainDAO, :DayDAO, :PreferenceDAO,
 :WhatEverDao... ]
DAOS.each do |dao|
bean(dao, "daos.hibernate.#{dao}Hibernate")
{|b| b.new("sonarSession")}
end

This snippet uses metaprogramming to create 20 odd DAOs in 8 lines of code.

Springy has matured since the first release when it was still in the proof-of-concept-stage. We’re using it successfully in Sonar, and there is no way we’ll ever go back to using XML for configuration. Anyway, XML is for girls, according to Hani.

My new favourite feature in JRuby is JavaUtilities.extend_proxy. Basically it allows you to extend an existing Java class with Ruby code. All instances of this class will then have additional Ruby methods on them. This can be handy to fix completely useless APIs like org.w3c.dom.Document. If you’ve ever used Ruby’s xml builder you will know what I mean.

JRuby allows us to do this:

JavaUtilities.
extend_proxy('com.sun...internal.dom.DocumentImpl') {
def tag(sym, *args, &block)
#ruby code omitted
end
}

doc = DocumentImpl.new
doc.tag("beans") do
doc.tag("bean", "id"=>"mybean") do
...
end
end
doc.validate!
doc.serialize(System.err)

DOM is finally usable! See serialization.rb for the full code.

SONAR brings statistical natural language processing and social network analysis to the problem of browsing and filtering large archives. We permit users to see who is talking to who, how much and about what. There are applications in areas including expertise discovery, compliance, forensics, search and alerting.

We are a small company, with large ambition. We number currently 10, and have just secured £3M of venture funding to help us grow our R&D efforts and establish a North American presence.

The SONAR platform consists of a very Ajaxy web front-end in Ruby on Rails, with a Java back-end doing the asynchronous natural language processing and social network analysis.

We are looking for software developers with experience in the following technologies :

Java, Hibernate, Spring framework, JMS, Ruby, Ruby on Rails, Transactions, Transactional messaging, SQL, MySQL, Oracle, Linux, Windows

Experience in all of the above is not a necessity. We are looking for smart people who can learn quickly, love solving difficult problems and can grow with the company. These attributes are far more important than any tick list.

If you are interested, please contact :

Craig McMillan, craig AT trampolinesystems DOT com

Please note : if you are an agency and are not already talking to us, then do not contact us. Really.

I’m a big fan of SVN, and I know it’s in very common use throughout the development community, so I thought I’d give a shout out to an interesting project that extracts some fascinating SVN stats and draws lots of pretty pictures - StatSVN

We’ve now added a StatSVN task to our build scripts, and the figures it kicks out are just great - once you start looking, you can lose yourself in there for ages….

To give some random samples:

• As of three days ago, there were 75130 lines of code in the Sonar trunk, of which Craig has contributed 33.6%, myself 32.1% and Jan 22.2%. As Jan has mostly been working on the Ruby On Rails interface, and Craig and I have mostly been writing the Java backend, what does this say about the relative expressive efficiency and productivity of each language?
• Craig took “Developer Of The Month” for February, with 5286 lines, taking over from me in January with 7546 lines.
• Over 80% of my changes are additions, with under 20% being updates. Craig is more or less the same, with a few percent more modifications - probably due to fixing my occasional “EVIL” quick hacks…
• By far and away the most commits overall get done between 4pm and 5pm, but personally, I do three times as many commits between 2pm and 3pm than any other hour. Probably because I keep saying to myself got to finish this before I go to lunch…
• Jan has not done a single commit before 12 noon :-) However, he’s the only person to have committed between 1am and 2am!
• I do a huge number of commits on a Monday (400+), followed by successively fewer every day until Friday (~60). Does this mean I’m fresher and more enthusiastic after the weekend, or is it that when I start the week, I go for the easiest tasks first, and ramp up towards the more difficult tasks as I go on? On the other hand, overall the most commits are done on a Friday, followed by Tuesday

You can also measure some metrics around files, rather than developers:

• Overall, across all file types, we have an average of around 40 lines of code per file
• 58.7% of the files in the repository are .java, but they contribute 73.3% of the total lines of code
• On average, each .rhtml template is just 26.6 lines of code
• The most amended file in the whole repository is the Rakefile!

I could go on for hours….but it’s nearly 2pm and I need to commit some code, dammit! So install StatSVN on your repository and have a play yourself. It’s fun.

i came across a problem with our java unit testing package, TestNG : our IHookable implementation, which sets up transaction contexts for test methods, wasn’t being given details of Exceptions which occurred during the running of the test methods

downloading the source for TestNG, it turned out to be an easy fix, a one-liner. i submitted a patch to cedric, and a couple of hours later it was accepted and checked in

if only all open source experiences were so smooth