Parent

Class/Module Index [+]

Quicksearch

Module

Extends the module object with module and instance accessors for class attributes, just like the native attr* accessors for instance attributes.

module AppConfiguration
  mattr_accessor :google_api_key
  self.google_api_key = "123456789"

  mattr_accessor :paypal_url
  self.paypal_url = "www.sandbox.paypal.com"
end

AppConfiguration.google_api_key = "overriding the api key!"

Public Instance Methods

as_load_path() click to toggle source

Returns String#underscore applied to the module name minus trailing classes.

ActiveRecord.as_load_path               # => "active_record"
ActiveRecord::Associations.as_load_path # => "active_record/associations"
ActiveRecord::Base.as_load_path         # => "active_record" (Base is a class)

The Kernel module gives an empty string by definition.

Kernel.as_load_path # => ""
Math.as_load_path   # => "math"
# File lib/active_support/core_ext/module/loading.rb, line 12
def as_load_path
  if self == Object || self == Kernel
    ''
  elsif is_a? Class
    parent == self ? '' : parent.as_load_path
  else
    name.split('::').collect do |word|
      word.underscore
    end * '/'
  end
end
attr_accessor_with_default(sym, default = nil, &block) click to toggle source

Declare an attribute accessor with an initial default return value.

To give attribute :age the initial value 25:

class Person
  attr_accessor_with_default :age, 25
end

some_person.age
=> 25
some_person.age = 26
some_person.age
=> 26

To give attribute :element_name a dynamic default value, evaluated in scope of self:

attr_accessor_with_default(:element_name) { name.underscore }
# File lib/active_support/core_ext/module/attr_accessor_with_default.rb, line 21
def attr_accessor_with_default(sym, default = nil, &block)
  raise 'Default value or block required' unless !default.nil? || block
  define_method(sym, block_given? ? block : Proc.new { default })
  module_eval(      def #{sym}=(value)                        # def age=(value)        class << self; attr_reader :#{sym} end  #   class << self; attr_reader :age end        @#{sym} = value                         #   @age = value      end                                       # end, __FILE__, __LINE__ + 1)
end
attr_internal(*attrs) click to toggle source
attr_internal_accessor(*attrs) click to toggle source

Declares an attribute reader and writer backed by an internally-named instance variable.

# File lib/active_support/core_ext/module/attr_internal.rb, line 18
def attr_internal_accessor(*attrs)
  attr_internal_reader(*attrs)
  attr_internal_writer(*attrs)
end
Also aliased as: attr_internal
attr_internal_reader(*attrs) click to toggle source

Declares an attribute reader backed by an internally-named instance variable.

# File lib/active_support/core_ext/module/attr_internal.rb, line 3
def attr_internal_reader(*attrs)
  attrs.each do |attr|
    module_eval "def #{attr}() #{attr_internal_ivar_name(attr)} end"
  end
end
attr_internal_writer(*attrs) click to toggle source

Declares an attribute writer backed by an internally-named instance variable.

# File lib/active_support/core_ext/module/attr_internal.rb, line 10
def attr_internal_writer(*attrs)
  attrs.each do |attr|
    module_eval "def #{attr}=(v) #{attr_internal_ivar_name(attr)} = v end"
  end
end
delegate(*methods) click to toggle source

Provides a delegate class method to easily expose contained objects' methods as your own. Pass one or more methods (specified as symbols or strings) and the name of the target object as the final :to option (also a symbol or string). At least one method and the :to option are required.

Delegation is particularly useful with Active Record associations:

class Greeter < ActiveRecord::Base
  def hello()   "hello"   end
  def goodbye() "goodbye" end
end

class Foo < ActiveRecord::Base
  belongs_to :greeter
  delegate :hello, :to => :greeter
end

Foo.new.hello   # => "hello"
Foo.new.goodbye # => NoMethodError: undefined method `goodbye' for #<Foo:0x1af30c>

Multiple delegates to the same target are allowed:

class Foo < ActiveRecord::Base
  belongs_to :greeter
  delegate :hello, :goodbye, :to => :greeter
end

Foo.new.goodbye # => "goodbye"

Methods can be delegated to instance variables, class variables, or constants by providing them as a symbols:

class Foo
  CONSTANT_ARRAY = [0,1,2,3]
  @@class_array  = [4,5,6,7]

  def initialize
    @instance_array = [8,9,10,11]
  end
  delegate :sum, :to => :CONSTANT_ARRAY
  delegate :min, :to => :@@class_array
  delegate :max, :to => :@instance_array
end

Foo.new.sum # => 6
Foo.new.min # => 4
Foo.new.max # => 11

Delegates can optionally be prefixed using the :prefix option. If the value is true, the delegate methods are prefixed with the name of the object being delegated to.

Person = Struct.new(:name, :address)

class Invoice < Struct.new(:client)
  delegate :name, :address, :to => :client, :prefix => true
end

john_doe = Person.new("John Doe", "Vimmersvej 13")
invoice = Invoice.new(john_doe)
invoice.client_name    # => "John Doe"
invoice.client_address # => "Vimmersvej 13"

It is also possible to supply a custom prefix.

class Invoice < Struct.new(:client)
  delegate :name, :address, :to => :client, :prefix => :customer
end

invoice = Invoice.new(john_doe)
invoice.customer_name    # => "John Doe"
invoice.customer_address # => "Vimmersvej 13"

If the object to which you delegate can be nil, you may want to use the :allow_nil option. In that case, it returns nil instead of raising a NoMethodError exception:

class Foo
  attr_accessor :bar
  def initialize(bar = nil)
    @bar = bar
  end
  delegate :zoo, :to => :bar
end

Foo.new.zoo   # raises NoMethodError exception (you called nil.zoo)

class Foo
  attr_accessor :bar
  def initialize(bar = nil)
    @bar = bar
  end
  delegate :zoo, :to => :bar, :allow_nil => true
end

Foo.new.zoo   # returns nil
# File lib/active_support/core_ext/module/delegation.rb, line 99
def delegate(*methods)
  options = methods.pop
  unless options.is_a?(Hash) && to = options[:to]
    raise ArgumentError, "Delegation needs a target. Supply an options hash with a :to key as the last argument (e.g. delegate :hello, :to => :greeter)."
  end

  if options[:prefix] == true && options[:to].to_s =~ /^[^a-z_]/
    raise ArgumentError, "Can only automatically set the delegation prefix when delegating to a method."
  end

  prefix = options[:prefix] && "#{options[:prefix] == true ? to : options[:prefix]}_"

  file, line = caller.first.split(':', 2)
  line = line.to_i

  methods.each do |method|
    on_nil =
      if options[:allow_nil]
        'return'
      else
        %(raise "#{prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}")
      end

    module_eval(        def #{prefix}#{method}(*args, &block)               # def customer_name(*args, &block)          #{to}.__send__(#{method.inspect}, *args, &block)  #   client.__send__(:name, *args, &block)        rescue NoMethodError                                # rescue NoMethodError          if #{to}.nil?                                     #   if client.nil?            #{on_nil}          else                                              #   else            raise                                           #     raise          end                                               #   end        end                                                 # end, file, line)
  end
end
included_in_classes() click to toggle source

Returns the classes in the current ObjectSpace where this module has been mixed in according to Module#included_modules.

module M
end

module N
  include M
end

class C
  include M
end

class D < C
end

p M.included_in_classes # => [C, D]
# File lib/active_support/core_ext/module/inclusion.rb, line 21
def included_in_classes
  classes = []
  ObjectSpace.each_object(Class) { |k| classes << k if k.included_modules.include?(self) }

  classes.reverse.inject([]) do |unique_classes, klass| 
    unique_classes << klass unless unique_classes.collect { |k| k.to_s }.include?(klass.to_s)
    unique_classes
  end
end
mattr_accessor(*syms) click to toggle source
# File lib/active_support/core_ext/module/attribute_accessors.rb, line 63
def mattr_accessor(*syms)
  mattr_reader(*syms)
  mattr_writer(*syms)
end
mattr_reader(*syms) click to toggle source
# File lib/active_support/core_ext/module/attribute_accessors.rb, line 16
def mattr_reader(*syms)
  options = syms.extract_options!
  syms.each do |sym|
    next if sym.is_a?(Hash)
    class_eval(        unless defined? @@#{sym}          @@#{sym} = nil        end        def self.#{sym}          @@#{sym}        end, __FILE__, __LINE__ + 1)

    unless options[:instance_reader] == false
      class_eval(          def #{sym}            @@#{sym}          end, __FILE__, __LINE__ + 1)
    end
  end
end
mattr_writer(*syms) click to toggle source
# File lib/active_support/core_ext/module/attribute_accessors.rb, line 40
def mattr_writer(*syms)
  options = syms.extract_options!
  syms.each do |sym|
    class_eval(        unless defined? @@#{sym}          @@#{sym} = nil        end        def self.#{sym}=(obj)          @@#{sym} = obj        end, __FILE__, __LINE__ + 1)

    unless options[:instance_writer] == false
      class_eval(          def #{sym}=(obj)            @@#{sym} = obj          end, __FILE__, __LINE__ + 1)
    end
  end
end
remove_possible_method(method) click to toggle source
# File lib/active_support/core_ext/module/remove_method.rb, line 2
def remove_possible_method(method)
  remove_method(method)
rescue NameError
end
synchronize(*methods) click to toggle source

Synchronize access around a method, delegating synchronization to a particular mutex. A mutex (either a Mutex, or any object that responds to synchronize and yields to a block) must be provided as a final :with option. The :with option should be a symbol or string, and can represent a method, constant, or instance or class variable. Example:

class SharedCache
  @@lock = Mutex.new
  def expire
    ...
  end
  synchronize :expire, :with => :@@lock
end
# File lib/active_support/core_ext/module/synchronization.rb, line 15
def synchronize(*methods)
  options = methods.extract_options!
  unless options.is_a?(Hash) && with = options[:with]
    raise ArgumentError, "Synchronization needs a mutex. Supply an options hash with a :with key as the last argument (e.g. synchronize :hello, :with => :@mutex)."
  end

  methods.each do |method|
    aliased_method, punctuation = method.to_s.sub(/([?!=])$/, ''), $1

    if method_defined?("#{aliased_method}_without_synchronization#{punctuation}")
      raise ArgumentError, "#{method} is already synchronized. Double synchronization is not currently supported."
    end

    module_eval(        def #{aliased_method}_with_synchronization#{punctuation}(*args, &block)     # def expire_with_synchronization(*args, &block)          #{with}.synchronize do                                                    #   @@lock.synchronize do            #{aliased_method}_without_synchronization#{punctuation}(*args, &block)  #     expire_without_synchronization(*args, &block)          end                                                                       #   end        end                                                                         # end, __FILE__, __LINE__ + 1)

    alias_method_chain method, :synchronization
  end
end

[Validate]

Generated with the Darkfish Rdoc Generator 2.