Class: Composition::Compositions::Compose

Inherits:
Composition
  • Object
show all
Defined in:
lib/composition/compositions/compose.rb

Instance Attribute Summary

Attributes inherited from Composition

#name

Instance Method Summary collapse

Methods inherited from Composition

#class_name, #initialize, #inverse_of, #klass

Constructor Details

This class inherits a constructor from Composition::Compositions::Composition

Instance Method Details

#actual_column_for(aliased_attribute) ⇒ Object 



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# File 'lib/composition/compositions/compose.rb', line 56

def actual_column_for(aliased_attribute)
  mapping.key(aliased_attribute)
end

#getter(ar) ⇒ Object

For a composition defined like:

class User < ActiveRecord::Base
  compose :credit_card,
          mapping: {
            credit_card_name: :name,
            credit_card_brand: :brand
          }
end

The getter method will be in charge of implementing @user.credit_card.

It is responsible for instantiating a new CreditCard object with the attributes from the de-normalized columns in User, and then return it.



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# File 'lib/composition/compositions/compose.rb', line 19

def getter(ar)
  attributes = attributes(ar)
  klass.new(attributes.merge(composed_from.name => ar)).tap(&:valid?) unless all_blank?(attributes)
end

#mapping ⇒ Object 



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# File 'lib/composition/compositions/compose.rb', line 52

def mapping
  @options[:mapping]
end

#setter(ar, setter_value) ⇒ Object

For a composition defined like:

class User < ActiveRecord::Base
  compose :credit_card,
          mapping: {
            credit_card_name: :name,
            credit_card_brand: :brand
          }
end

The setter method will be in charge of implementing @user.credit_card=.

setter_value can be either a credit_card instance or a hash of attributes and the setter will only set the @credit_card attributes that are included in the hash. This means that if a credit_card attribute is not given in the hash then we’ll set it with the value from the @user de-normalized column. The reason behind this is to imitate how ActiveRecord assign_attributes method works.



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# File 'lib/composition/compositions/compose.rb', line 41

def setter(ar, setter_value)
  nil_columns(ar) and return if setter_value.nil?
  attributes = setter_value.to_h.with_indifferent_access

  mapping.each do |actual_column, composed_alias|
    ar.send("#{actual_column}=", attributes[composed_alias]) if attributes.key?(composed_alias)
  end

  setter_value
end