Module: Tableless::ClassMethods

Included in:
ActiveRecord::TablelessModel
Defined in:
lib/tableless_model/class_methods.rb

Instance Method Summary collapse

Instance Method Details

#attribute(name, options = {}) ⇒ Object

Macro to define an attribute of the Tableless model. To be used as follows in a tableless model:

class Example < ActiveRecord::TablelessModel

  attribute :name,    :type => :string
  attribute :active,  :type => :boolean, :default => true

end



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# File 'lib/tableless_model/class_methods.rb', line 17

def attribute(name, options = {})
  attribute_name = name.to_s

  # Defining the new attribute for the tableless model
  self.attributes[name] = options

  # Defining method-like getter and setter for the new attribute
  # so it can be used like a regular object's property
  class_eval %Q{
    def #{attribute_name}
      self[:#{attribute_name}]
    end

    def #{attribute_name}=(value)
      self[:#{attribute_name}] = value
    end
  }
end

#cast(attribute_name, value) ⇒ Object

If a data type has been specified for an attribute, its value will be converted accordingly (if necessary) when getting or setting it



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# File 'lib/tableless_model/class_methods.rb', line 54

def cast(attribute_name, value)
  type = self.attributes[attribute_name][:type] || :string

  return nil if value.nil? && ![:string, :integer, :boolean, :float, :decimal].include?(type)

  begin
    case type
      when :string    then (value.is_a?(String) ? value : String(value))
      when :integer   then (value.is_a?(Integer) ? value : value.to_s.to_i)
      when :float     then (value.is_a?(Float) ? value : value.to_s.to_f)
      when :decimal   then (value.is_a?(BigDecimal) ? value : BigDecimal(value.to_s))
      when :time      then (value.is_a?(Time) ? value : Time.parse(value))
      when :date      then (value.is_a?(Date) ? value : Date.parse(value))
      when :datetime  then (value.is_a?(DateTime) ? value : DateTime.parse(value))
      when :boolean   then (["true", "1"].include?(value.to_s))
      else value
    end
  rescue Exception => e
    raise StandardError, "Invalid value #{value.inspect} for attribute #{attribute_name} - expected data type is #{type.to_s.capitalize} but value is a #{value.class} (Exception details: #{e})"    
    value
  end
end

#inherited(klass) ⇒ Object

Initialises @attributes in the context of the class inheriting from the Tableless model



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# File 'lib/tableless_model/class_methods.rb', line 41

def inherited(klass)
  super
  (@subclasses ||= Set.new) << klass
  klass.instance_variable_set("@attributes",  Hash.new)
end