00_jim_gay_refactor_process.md

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PATH to East Oriented

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original

class Person attr_reader :address # street #house num # city, ST zipcode # format correctly depending on the info we have # BAD CODE!!! (we know too much about Address) def display_address ''.tap do |string| string << address.street unless address.street&.empty? string << "\n" unless string.empty? string << address.city unless address.city&.empty? string << ", " if !address.city&.empty? && (!address.state&.empty? || !address.zipcode.empty?) string << address.state unless address.state&.empty?
string << " " unless address.state&.empty? || address.zipcode&.empty? string << address.zipcode unless address.state&.empty? end end end

Refactor 1

class Person attr_reader :address def display_address address.display self end end class Address # ok to query self (rule 2) def diplay(line_break="\n") state_and_zipcode = [state, zipcode].compact.join(' ') state_and_zipcode = nil if state_and_zipcode.empty?

    city_state_zip    = [city, state_and_zipcode].compact.join(' ')
    city_state_zip    = nil    if city_state_zip.empty?

    # [street, city_state_zip].compact.join("\n")
    [street, city_state_zip].compact.join(line_break)
end

end

Refactor 2

class Person def display_address address.display(template=AddressTextTemplate.new) self end end class Address # ok to query self (rule 2) def diplay(template) template.display_address(self) self end end class AddressTextTemplate # ok to query self (rule 2) def display_address(address) state_and_zipcode = [address.state, address.zipcode].compact.join(' ') state_and_zipcode = nil if state_and_zipcode.empty?

    city_state_zip    = [address.city, state_and_zipcode].compact.join(', ')
    city_state_zip    = nil    if city_state_zip.empty?

    STDOUT.puts [address.street, city_state_zip].compact.join("\n")

    self
end

end class AddressHtmlTemplate # ok to query self (rule 2) def display_address(address) state_and_zipcode = [address.state, address.zipcode].compact.join(' ') state_and_zipcode = nil if state_and_zipcode.empty?

    city_state_zip    = [address.city, state_and_zipcode].compact.join(', ')
    city_state_zip    = nil    if city_state_zip.empty?


    File.open 'address.html' do |file|
        file.write [address.street, city_state_zip].compact.join("<br/>")
    end

    self
end

end

Refactor 3

make it hard to violate demeter! block querying (send value objects)

class Person def display_address address.display(template=AddressTextTemplate.new) self end private attr_reader :address end class Address # ok to query self (rule 2) def diplay(template) template.display_address(self.to_value) self end private attr_reader :street, :city, :state, :zipcode # create a value object require 'ostruct' def to_value # protect privacy - no street address to display OpenStruct.new(street: nil, city: city, state: state, zipcode: zipcode) end def to_value_shippable # when priveledge user needs to ship package to user OpenStruct.new(street: street, city: city, state: state, zipcode: zipcode) end end class AddressTextTemplate # ok to query self (rule 2) def display_address(address) state_and_zipcode = [address.state, address.zipcode].compact.join(' ') state_and_zipcode = nil if state_and_zipcode.empty?

    city_state_zip    = [address.city, state_and_zipcode].compact.join(', ')
    city_state_zip    = nil    if city_state_zip.empty?

    STDOUT.puts [address.street, city_state_zip].compact.join("\n")

    self
end

end class AddressHtmlTemplate # ok to query self (rule 2) def display_address(address) state_and_zipcode = [address.state, address.zipcode].compact.join(' ') state_and_zipcode = nil if state_and_zipcode.empty?

    city_state_zip    = [address.city, state_and_zipcode].compact.join(', ')
    city_state_zip    = nil    if city_state_zip.empty?


    File.open 'address.html' do |file|
        file.write [address.street, city_state_zip].compact.join("<br/>")
    end

    self
end

end