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 



53
54
55
56
 
# 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

:nodoc:



4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
 
# 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 



31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
 
# 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 



66
67
68
69
 
# 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 



71
72
73
74
 
# 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 



38
39
40
41
42
43
44
45
46
47
48
49
50
 
# 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 



76
77
78
79
 
# 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 



52
53
54
55
56
57
58
59
60
61
62
63
64
 
# 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

:nodoc:



10
11
12
13
14
15
16
17
18
19
20
21
22
 
# 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 



24
25
26
27
28
29
30
31
32
33
34
35
36
 
# 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_attributes ⇒ Object 



81
82
83
 
# File 'lib/active_support/class_inheritable_attributes.rb', line 81

def inheritable_attributes
  @inheritable_attributes ||= {}
end

#read_inheritable_attribute(key) ⇒ Object 



99
100
101
 
# File 'lib/active_support/class_inheritable_attributes.rb', line 99

def read_inheritable_attribute(key)
  inheritable_attributes[key]
end

#remove_subclasses ⇒ Object 



37
38
39
 
# File 'lib/active_support/core_ext/object_and_class.rb', line 37

def remove_subclasses
  Object.remove_subclasses_of(self)
end

#reset_inheritable_attributes ⇒ Object 



103
104
105
 
# File 'lib/active_support/class_inheritable_attributes.rb', line 103

def reset_inheritable_attributes
  inheritable_attributes.clear
end

#subclasses ⇒ Object 



41
42
43
 
# File 'lib/active_support/core_ext/object_and_class.rb', line 41

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

#write_inheritable_array(key, elements) ⇒ Object 



89
90
91
92
 
# 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 



85
86
87
 
# 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 



94
95
96
97
 
# 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