Simple and Easy way to run a java class.

easyjava

#!/usr/bin/env ruby

# ## An Easy Way to Compile and Run Java Classes
#
# System utility for compiling and running Java classes
# in a specific directory structure.
#
# #### Recommended Installation
# Save this code to a file named `easyjava`, somewhere on your HD. Then
# in your `~/.bash_profile` add the following:
#
#     alias easyjava="/path/to/easyjava"
#
# #### Directory structure
# The bin folder will be automatically created if you don't have one.
#
#     project/
#            |
#            |- src/
#            |- bin/
#
# #### Usage
# It is required that you be executing this script from the projects directory.
#
#     easyjava AClass
#

require 'optparse'

# All of the options parsed from the commandline.
options = {}

optparse = OptionParser.new do |opts|

  # Help banner
  opts.banner = "Usage: easyjava [options] class"
  opts.on( '-h', '--help', 'Display this screen' ) do
    puts opts
    exit
  end
end
optparse.parse!

unless ARGV.size == 1
  puts optparse.help
  exit
end

# Ensure we have a src folder, quit if not.
unless File.directory? 'src'
  puts "No src directory found."
  exit
end

# Ensure we have a bin folder, make one if not.
Dir.mkdir "bin" unless File.directory? 'bin'

# The class we want to run.
klass = ARGV[0]

compile = system "javac -d bin src/*.java"
system "java -cp bin #{klass}" if compile