class Hashie::Trash
A Trash is a 'translated' Dash where the keys can be remapped from a source hash.
Trashes are useful when you need to read data from another application, such as a Java api, where the keys are named differently from how we would in Ruby.
Public Class Methods
Defines a property on the Trash. Options are as follows:
-
:default
- Specify a default value for this property, to be
returned before a value is set on the property in a new Dash.
-
:from
- Specify the original key name that will be write only. -
:with
- Specify a lambda to be used to convert value. -
:transform_with
- Specify a lambda to be used to convert value
without using the :from option. It transform the property itself.
# File lib/hashie/trash.rb, line 20 def self.property(property_name, options = {}) super if options[:from] if property_name.to_sym == options[:from].to_sym raise ArgumentError, "Property name (#{property_name}) and :from option must not be the same" end translations << options[:from].to_sym if options[:with].respond_to? :call class_eval do define_method "#{options[:from]}=" do |val| self[property_name.to_sym] = options[:with].call(val) end end else class_eval <<-RUBY def #{options[:from]}=(val) self[:#{property_name}] = val end RUBY end elsif options[:transform_with].respond_to? :call transforms[property_name.to_sym] = options[:transform_with] end end
Private Class Methods
# File lib/hashie/trash.rb, line 64 def self.transforms @transforms ||= {} end
# File lib/hashie/trash.rb, line 60 def self.translations @translations ||= [] end
Public Instance Methods
Set a value on the Dash in a Hash-like way. Only works on pre-existing properties.
# File lib/hashie/trash.rb, line 48 def []=(property, value) if self.class.translations.include? property.to_sym send("#{property}=", value) elsif self.class.transforms.key? property.to_sym super property, self.class.transforms[property.to_sym].call(value) elsif property_exists? property super end end
Private Instance Methods
Deletes any keys that have a translation
# File lib/hashie/trash.rb, line 80 def initialize_attributes(attributes) return unless attributes attributes_copy = attributes.dup.delete_if do |k,v| if self.class.translations.include?(k.to_sym) self[k] = v true end end super attributes_copy end
Raises an NoMethodError if the property doesn't exist
# File lib/hashie/trash.rb, line 70 def property_exists?(property) unless self.class.property?(property.to_sym) raise NoMethodError, "The property '#{property}' is not defined for this Trash." end true end