Ruby Class Initialize with Hash Arguments

init_with_hash.rb

def initialize(args = {})
  defaults = {
    :file_list_cache_dir    => 'cache/filelists/',
    :img_root    => 'cache/img/',
    :sensor_res_img_root => 'cache/srimg/'
  }
  defaults.merge(args).each do |attr, val|
    instance_variable_set("@#{attr}", val) if defaults.has_key?(attr) && (not val.nil?)
  end if args
  setup
end