A (very) simple Java console

jConsole.rb

#!jruby

unless RUBY_PLATFORM === "java"
   puts "jConsole only works with jRuby"
   puts "For more informations, see http://www.jruby.org/"
   exit 1
end

require 'readline'
require 'rubygems'
begin
require 'term/ansicolor'
rescue
   puts "please install term/ansicolor : "
   puts "  [sudo] gem install term-ansicolor"
   exit 1
end
require 'inline'
begin
require 'java_inline'
rescue
   puts "please install java-inline : "
   puts "  [sudo] gem install java-inline"
   exit 1
end
require 'java'

class JConsole 
   class Runner
      def initialize
         clean
      end
   
      def clean
         @complete_source = nil
         @imports = []
         @java_klass = nil
      end
   
      def unimport(packages) 
         @imports -= packages
      end
   
      def import(packages)
         if packages.size == 0
            @imports.each { |i| puts "\t#{i}" }
         else
            @imports += packages
         end
      end
   
      def uniline(data)
         methodName = create_uniline_method(data)
         compile
         @java_klass.send(methodName.to_sym)
      end
   
      private
   
      def compile
         source = @complete_source
         imp = @imports
         jKlass = Class.new do 
            inline :Java do |builder|
               imp.each { |i| 
                  builder.import i 
               }
               builder.java source
            end
         end
         @java_klass = jKlass.new
      end
   
      def create_uniline_method(data)
         methodName = "x"+Time.now.to_i.to_s
         @complete_source = "
public static void #{methodName}() { 
  #{data}
}
         "
         methodName
      end
   end

   def initialize
      @runner = Runner.new
      @runner.uniline("System.out.println(\"jConsole with Java \" + System.getProperty(\"os.version\"));")
      @run = true
      ENV['CLASSPATH'] = "." if ENV['CLASSPATH'].nil?
   end

   def jrun?(data)
      [["(", ")"], ["{", "}"], ["[", "]"]].each do |e|
         return false if data.count(e[0]) != data.count(e[1])
      end
      return true
   end

   def command(args)
      action = args.shift.to_sym
      run = false
      case action
      when :import
         @runner.import args
      when :unimport
         @runner.unimport args
      when :run
         @run = !@run
         print Term::ANSIColor.yellow, "run #{ @run ? 'ON' : 'OFF' }\n", Term::ANSIColor.clear
         run = true
      when :help
         help
      when :quit
         exit 0
      else 
         print Term::ANSIColor.red, "Command `\\#{action}' undefined! Try \\help\n", Term::ANSIColor.clear
      end

      return run
   end

   def help
      print Term::ANSIColor.blue
      puts "\\import [PACKAGE]   : Import package PACKAGE or display imports if no package given"
      puts "\\unimport [PACKAGE] : Remove package PACKAGE import"
      puts "\\run                : Set auto-run on/off"
      puts ""
      puts "\\help               : Display help"
      puts "\\quit               : Quit jConsole"
      puts ""
      puts "CLASSPATH set to : "+ENV['CLASSPATH']
      print Term::ANSIColor.clear
   end

   def run
      kode = ""
      print Term::ANSIColor.green
      while line = Readline.readline( "> ", true )
         run = true
         if line =~ /^\\/
            run = command line.chomp.gsub(/^\\/, "").split(" ")
            line = ""
         end

         print Term::ANSIColor.clear
         if run
            unless jrun?(kode+line) && @run
               kode += line
            else
               @runner.uniline(kode+line.chomp)
               kode = ""
            end
         end
         print Term::ANSIColor.green
      end
      print Term::ANSIColor.clear
   end
end

JConsole.new.run