Module: SafetyModule

Defined in:
lib/safety/safety_module.rb

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Object 



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# File 'lib/safety/safety_module.rb', line 11

def method_missing(method, *args, &block)
  type = SafetyAttributeHelper.parse_attribute_type method
  if type
    # Extract the type name from the attribute declaration
    type_name = method.to_s.slice("attr_#{type.to_s}_".length...method.to_s.length)
    
    # If the type name is var, type safety will be disabled for this attribute
    should_enforce_type_safety = type_name != 'var'
    
    # The class to enforce type safety on
    type_safe_class = nil
    
    # Get the type, which could be deep in modules
    if should_enforce_type_safety == true
      type_safe_class = type_name.split('::').inject(Object.class) do |current_module, class_name|
        current_module.const_get(class_name)
      end
    end

    # Define enforce safety for this property
    define_method "__enforce_safety_#{args[0]}".to_sym do |value|
      # If enforcing type and value is not of type safe class, raise TypeError
      if should_enforce_type_safety == true and value.is_a?(type_safe_class) == false
        raise TypeError, "Type Safe Attribute \"#{args[0]}\", of type \"#{type_safe_class}\", set to value \"#{value}\" of class \"#{value.class}\"."
      end
      return value
    end

    # A way to get the default value
    define_method "__default_value_#{args[0]}".to_sym do
      if args[1] != nil
        return args[1]
      else
        return nil
      end
    end
    
    # Set default, if one was provided
    #set_value.call(args[1]) if args[1] != nil
    define_method "__lazy_instantiator_#{args[0]}".to_sym do
      return block
    end

    lazy_instantiation = <<EVAL
def __lazy_instantiation_#{args[0]}
return nil if __lazy_instantiator_#{args[0]}().nil?
instance_exec &__lazy_instantiator_#{args[0]}
end
EVAL

    getter = <<EVAL
def #{args[0]}
@#{args[0]} = __lazy_instantiation_#{args[0]} if @#{args[0]}.nil? && __lazy_instantiator_#{args[0]} != nil
@#{args[0]} = __enforce_safety_#{args[0]}(__default_value_#{args[0]}) if @#{args[0]}.nil? && __default_value_#{args[0]} != nil
__enforce_safety_#{args[0]}(@#{args[0]})
end
EVAL

    setter = <<EVAL
def #{args[0]}= value
@#{args[0]} = __enforce_safety_#{args[0]}(value)
end
EVAL

    to_evaluate = lazy_instantiation
    case type
    when :accessor
      to_evaluate << getter
      to_evaluate << setter
    when :reader
      to_evaluate << getter
    when :writer
      to_evaluate << setter
    end
    
    self.class_eval to_evaluate
  else
    super
  end
end

Instance Method Details

#respond_to?(method) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/safety/safety_module.rb', line 3

def respond_to?(method)
  if SafetyAttributeHelper.parse_attribute_type method
    true
  else
    super
  end
end