ext_helper_java.rb

#
# a version of setup_extension for Java
#
def setup_extension_java(extension_name, gem_spec = nil)
  ext_name = "#{extension_name}.jar"
  directory 'lib'

  unless File.directory?("ext/#{extension_name}")
    desc 'Compile Extension for current Ruby (= compile:jruby)'
    task :compile => [ 'compile:jruby' ] if JRUBY

    namespace :compile do
      desc "Compile Java Extension for JRuby"
      #task :jruby => ["lib/#{ext_name}"]

      task :jruby do
        begin
          # gem 'buildr', '1.3.1.1'
          # require 'buildr'
          # FIXME: this is throwing rspec activation errors
          sh %{jruby -S buildr package}

          buildr_output = extension_name.gsub(/_(ext)$/, '-\1-java-1.0.jar')
          cp "ext-java/target/#{buildr_output}", "lib/#{ext_name}"
        rescue LoadError
          puts "#{spec.name} requires the buildr gem to compile the Java extension"
        end
      end
    end
    file "lib/#{ext_name}" => 'compile:jruby'

  end
end