mess.rb

#########################################
# Run the following to generate some input:
#   find . -iname '*.java' -type f -exec cat {} \; | grep -E '^(package|import)'
# Then run this script to generate a .dot file for importing into graphiz

require 'set'

@dependencies = Hash.new { |hash, key| hash[key] = Set.new }

def add_dependency?(from, to)
  @dependencies[from].add?(to)
end

def print_dependency(from, to)
  if add_dependency?(from, to)
    puts %(  "#{from}" -> "#{to}";)
  end
end

def process_package(name)
  @package_name = name
end

def package_name_for(class_name)
  class_name.split(".")[0..-2].join(".")
end

def process_import(name)
  print_dependency(@package_name, package_name_for(name))
end

def dispatch(line)
  case line
  when /^package\s+(.*);$/ then process_package($1)
  when /^import\s+(.*);$/ then process_import($1)
  else raise "Invalid line: '#{line}'"
  end
end

def print_header
  puts "digraph G {"
end

def process(stream)
  stream.each_line { |line| dispatch(line.chomp) }
end

def print_footer
  puts "}"
end

print_header
process($<)
print_footer