Class: Class

Inherits:
Object show all
Defined in:
lib/active_support/class_attribute_accessors.rb,
lib/active_support/core_ext/object_and_class.rb,
lib/active_support/class_inheritable_attributes.rb

Overview

Allows attributes to be shared within an inheritance hierarchy, but where each descendant gets a copy of their parents' attributes, instead of just a pointer to the same. This means that the child can add elements to, for example, an array without those additions being shared with either their parent, siblings, or children, which is unlike the regular class-level attributes that are shared across the entire hierarchy.

Instance Method Summary collapse

Instance Method Details

#cattr_accessor(*syms) ⇒ Object


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# File 'lib/active_support/class_attribute_accessors.rb', line 53

def cattr_accessor(*syms)
  cattr_reader(*syms)
  cattr_writer(*syms)
end

#cattr_reader(*syms) ⇒ Object


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# File 'lib/active_support/class_attribute_accessors.rb', line 4

def cattr_reader(*syms)
  syms.select { |sym| sym.respond_to?(:id2name) }.each do |sym|
    class_eval <<-EOS
      if ! defined? @@#{sym.id2name}
        @@#{sym.id2name} = nil
      end
      
      def self.#{sym.id2name}
        @@#{sym}
      end

      def #{sym.id2name}
        @@#{sym}
      end

      def call_#{sym.id2name}
        case @@#{sym.id2name}
          when Symbol then send(@@#{sym})
          when Proc   then @@#{sym}.call(self)
          when String then @@#{sym}
          else nil
        end
      end
    EOS
  end
end

#cattr_writer(*syms) ⇒ Object


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# File 'lib/active_support/class_attribute_accessors.rb', line 31

def cattr_writer(*syms)
  syms.select { |sym| sym.respond_to?(:id2name) }.each do |sym|
    class_eval <<-EOS
      if ! defined? @@#{sym.id2name}
        @@#{sym.id2name} = nil
      end
      
      def self.#{sym.id2name}=(obj)
        @@#{sym.id2name} = obj
      end

      def self.set_#{sym.id2name}(obj)
        @@#{sym.id2name} = obj
      end

      def #{sym.id2name}=(obj)
        @@#{sym} = obj
      end
    EOS
  end
end

#class_inheritable_accessor(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 66

def class_inheritable_accessor(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_writer(*syms)
end

#class_inheritable_array(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 71

def class_inheritable_array(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_array_writer(*syms)
end

#class_inheritable_array_writer(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 38

def class_inheritable_array_writer(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}=(obj)
        write_inheritable_array(:#{sym}, obj)
      end

      def #{sym}=(obj)
        self.class.#{sym} = obj
      end
    EOS
  end
end

#class_inheritable_hash(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 76

def class_inheritable_hash(*syms)
  class_inheritable_reader(*syms)
  class_inheritable_hash_writer(*syms)
end

#class_inheritable_hash_writer(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 52

def class_inheritable_hash_writer(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}=(obj)
        write_inheritable_hash(:#{sym}, obj)
      end

      def #{sym}=(obj)
        self.class.#{sym} = obj
      end
    EOS
  end
end

#class_inheritable_reader(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 10

def class_inheritable_reader(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}
        read_inheritable_attribute(:#{sym})
      end

      def #{sym}
        self.class.#{sym}
      end
    EOS
  end
end

#class_inheritable_writer(*syms) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 24

def class_inheritable_writer(*syms)
  syms.each do |sym|
    class_eval <<-EOS
      def self.#{sym}=(obj)
        write_inheritable_attribute(:#{sym}, obj)
      end

      def #{sym}=(obj)
        self.class.#{sym} = obj
      end
    EOS
  end
end

#inheritable_attributesObject


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# File 'lib/active_support/class_inheritable_attributes.rb', line 81

def inheritable_attributes
  @inheritable_attributes ||= {}
end

#read_inheritable_attribute(key) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 99

def read_inheritable_attribute(key)
  inheritable_attributes[key]
end

#remove_subclassesObject


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# File 'lib/active_support/core_ext/object_and_class.rb', line 48

def remove_subclasses
  Object.remove_subclasses_of(self)
end

#reset_inheritable_attributesObject


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# File 'lib/active_support/class_inheritable_attributes.rb', line 103

def reset_inheritable_attributes
  inheritable_attributes.clear
end

#subclassesObject


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# File 'lib/active_support/core_ext/object_and_class.rb', line 52

def subclasses
  Object.subclasses_of(self).map { |o| o.to_s }
end

#write_inheritable_array(key, elements) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 89

def write_inheritable_array(key, elements)
  write_inheritable_attribute(key, []) if read_inheritable_attribute(key).nil?
  write_inheritable_attribute(key, read_inheritable_attribute(key) + elements)
end

#write_inheritable_attribute(key, value) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 85

def write_inheritable_attribute(key, value)
  inheritable_attributes[key] = value
end

#write_inheritable_hash(key, hash) ⇒ Object


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# File 'lib/active_support/class_inheritable_attributes.rb', line 94

def write_inheritable_hash(key, hash)
  write_inheritable_attribute(key, {}) if read_inheritable_attribute(key).nil?
  write_inheritable_attribute(key, read_inheritable_attribute(key).merge(hash))
end