Ruby hash to Java properties file

java_properties.rb

class Hash
  def to_java_properties_hash(prefix='')
    properties = {}

    self.each do |property, value|
      new_prefix = prefix.empty? ? property.to_s : prefix + '.' + property.to_s
      if value.respond_to? :to_java_properties_hash
        properties.merge!(value.to_java_properties_hash(new_prefix))
      else
        properties[new_prefix] = value.to_s
      end
    end

    # return the sorted hash
    Hash[ properties.sort_by { |k,v| k.to_s } ]
  end

  def to_java_properties_lines
    lines = []

    self.to_java_properties_hash.each do |k,v|
      # escape '=', ':', and newline ("\n") with a backslash
      lines << "#{k.gsub(/([=:\n])/, '\\\\\1')}=#{v.gsub(/([=:\n])/, '\\\\\1')}"
    end

    lines
  end

  def to_java_properties_string
    self.to_java_properties_lines.join("\n")
  end
end

java_properties_spec.rb

describe Hash do
  let(:properties) do
    {
      'a' => 'b',
      'c.4' => {
        :blue => 'green',
        'purple' => {
          11 => '14'
        },
        '11.12' => 'http://rundeck.url/A=B&C=D'
      },
      '_' => '!@#$%^&*()'
    }
  end

  describe '#to_java_properties_hash' do
    it 'returns a java properties hash' do
      expect(properties.to_java_properties_hash).to eql({
        "_" => "!@\#$%^&*()",
        "a" => "b",
        "c.4.11.12" => "http://rundeck.url/A=B&C=D",
        "c.4.blue" => "green",
        "c.4.purple.11" => "14"
      })
    end

    it 'returns a hash sorted by key' do
      expect({ c: 'd', a: 'b' }.to_java_properties_hash.keys).to eql(['a', 'c'])
      expect({ c: 'd', a: 'b' }.to_java_properties_hash.keys).to_not eql(['c', 'a'])
    end
  end

  describe '#to_java_properties_lines' do
    it 'returns java properties file lines' do
      expect(properties.to_java_properties_lines).to eql([
        "_=!@\#$%^&*()",
        "a=b",
        "c.4.11.12=http\\://rundeck.url/A\\=B&C\\=D",
        "c.4.blue=green",
        "c.4.purple.11=14"
      ])
    end
  end

  describe '#to_java_properties_string' do
    it 'returns java properties file content' do
      expect(properties.to_java_properties_string).to eql(
'_=!@#$%^&*()
a=b
c.4.11.12=http\://rundeck.url/A\=B&C\=D
c.4.blue=green
c.4.purple.11=14'
      )
    end
  end
end