Class: Reindeer::Meta::Attribute

Inherits:
Object
  • Object
show all
Defined in:
lib/reindeer/meta/attribute.rb

Defined Under Namespace

Classes: AttributeError

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, opts) ⇒ Attribute

Returns a new instance of Attribute.



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# File 'lib/reindeer/meta/attribute.rb', line 18

def initialize(name, opts)
  @name = name
  process_opts opts
end

Instance Attribute Details

#default_value ⇒ Object (readonly)

Returns the value of attribute default_value.



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# File 'lib/reindeer/meta/attribute.rb', line 13

def default_value
  @default_value
end

#handles ⇒ Object (readonly)

Returns the value of attribute handles.



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# File 'lib/reindeer/meta/attribute.rb', line 16

def handles
  @handles
end

#is_a ⇒ Object (readonly)

Returns the value of attribute is_a.



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# File 'lib/reindeer/meta/attribute.rb', line 11

def is_a
  @is_a
end

#is_bare ⇒ Object (readonly)

Returns the value of attribute is_bare.



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# File 'lib/reindeer/meta/attribute.rb', line 9

def is_bare
  @is_bare
end

#is_ro ⇒ Object (readonly)

Returns the value of attribute is_ro.



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# File 'lib/reindeer/meta/attribute.rb', line 9

def is_ro
  @is_ro
end

#is_rw ⇒ Object (readonly)

Returns the value of attribute is_rw.



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# File 'lib/reindeer/meta/attribute.rb', line 9

def is_rw
  @is_rw
end

#lazy_build ⇒ Object (readonly)

Returns the value of attribute lazy_build.



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# File 'lib/reindeer/meta/attribute.rb', line 14

def lazy_build
  @lazy_build
end

#lazy_builder ⇒ Object (readonly)

Returns the value of attribute lazy_builder.



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# File 'lib/reindeer/meta/attribute.rb', line 14

def lazy_builder
  @lazy_builder
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/reindeer/meta/attribute.rb', line 7

def name
  @name
end

#type_of ⇒ Object (readonly)

Returns the value of attribute type_of.



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# File 'lib/reindeer/meta/attribute.rb', line 11

def type_of
  @type_of
end

Instance Method Details

#get_default_value ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 95

def get_default_value
  default_value.call
end

#has_default? ⇒ Boolean

There must be a cleaner way to get a boolean.

Returns:

  • (Boolean) 


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# File 'lib/reindeer/meta/attribute.rb', line 104

def has_default?
  not default_value.nil?
end

#has_handles? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/reindeer/meta/attribute.rb', line 110

def has_handles?
  not handles.nil?
end

#install_accessors_in(klass) ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 36

def install_accessors_in(klass)
  return if is_bare

  if is_lazy?
    attr_name = to_var
    builder   = lazy_builder
    klass.__send__ :define_method, name, Proc.new {
      if instance_variable_defined? attr_name
        instance_variable_get attr_name
      else
        meta.get_attribute(attr_name).set_value_for(
          self, 
          builder.is_a?(Symbol) ? __send__(builder) : builder.call()
        )
      end
    }
  else
    name_sym = name
    klass.class_eval { self.__send__ :attr_reader, name_sym }
    if is_rw
      klass.__send__ :define_method, "#{name}=", Proc.new {|v|
        meta.get_attribute(name_sym).set_value_for(self, v)
      }
    end
  end
end

#install_clearer_in(klass) ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 63

def install_clearer_in(klass)
  attr_name = to_var
  klass.__send__ :define_method, "clear_#{name}!", Proc.new {
    remove_instance_variable attr_name
  }
end

#install_delegators(klass) ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 77

def install_delegators(klass)
  attr_name = to_var
  handles.each do |method|
    klass.__send__ :define_method, method, Proc.new {|*args|
      instance_variable_get(attr_name).__send__(method, *args)
    }
  end
end

#install_methods_in(klass) ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 27

def install_methods_in(klass)
  install_accessors_in klass
  if lazy_build
    install_clearer_in   klass
    install_predicate_in klass
  end
  install_delegators klass if has_handles?
end

#install_predicate_in(klass) ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 70

def install_predicate_in(klass)
  attr_name = to_var
  klass.__send__ :define_method, "has_#{name}?", Proc.new {
    instance_variable_defined? attr_name
  }
end

#is_lazy? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/reindeer/meta/attribute.rb', line 107

def is_lazy?
  not @lazy_builder.nil?
end

#required? ⇒ Boolean

Predicates

Returns:

  • (Boolean) 


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# File 'lib/reindeer/meta/attribute.rb', line 100

def required?
  @required
end

#set_value_for(instance, value) ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 86

def set_value_for(instance, value)
  if is_a and not value.is_a? is_a
    raise Meta::Attribute::AttributeError,
         "The value for '#{name}' of type '#{value.class}' is not a '#{is_a}'"
  end
  type_of.check_constraint(value) if type_of
  instance.instance_variable_set to_var, value
end

#to_var ⇒ Object 



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# File 'lib/reindeer/meta/attribute.rb', line 23

def to_var
  "@#{name.to_s}"
end