Module: SingleForwardable
Relationships & Source Files | |
Defined in: | lib/forwardable.rb |
Overview
SingleForwardable
can be used to setup delegation at the object level as well.
printer = String.new
printer.extend SingleForwardable # prepare object for delegation
printer.def_delegator "STDOUT", "puts" # add delegation for STDOUT.puts()
printer.puts "Howdy!"
Also, SingleForwardable
can be used to set up delegation for a Class or Module.
class Implementation
def self.service
puts "serviced!"
end
end
module Facade
extend SingleForwardable
def_delegator :Implementation, :service
end
Facade.service #=> serviced!
If you want to use both ::Forwardable and SingleForwardable
, you can use methods def_instance_delegator and def_single_delegator, etc.
Instance Method Summary
-
#def_delegator(accessor, method, ali = method)
Alias for #def_single_delegator.
-
#def_delegators(accessor, *methods)
Alias for #def_single_delegators.
-
#def_single_delegator(accessor, method, new_name = method)
(also: #def_delegator)
Defines a method method which delegates to accessor (i.e. it calls the method of the same name in accessor).
-
#def_single_delegators(accessor, *methods)
(also: #def_delegators)
Shortcut for defining multiple delegator methods, but with no provision for using a different name.
-
#delegate(hash)
Alias for #single_delegate.
-
#delegate(method) ⇒ accessor
(also: #delegate)
Takes a hash as its argument.
Instance Method Details
#def_delegator(accessor, method, ali = method)
Alias for #def_single_delegator.
# File 'lib/forwardable.rb', line 291
alias def_delegator def_single_delegator
#def_delegators(accessor, *methods)
Alias for #def_single_delegators.
# File 'lib/forwardable.rb', line 290
alias def_delegators def_single_delegators
#def_single_delegator(accessor, method, new_name = method) Also known as: #def_delegator
Defines a method method which delegates to accessor (i.e. it calls the method of the same name in accessor). If new_name is provided, it is used as the name for the delegate method.
# File 'lib/forwardable.rb', line 283
def def_single_delegator(accessor, method, ali = method) gen = Forwardable._delegator_method(self, accessor, method, ali) instance_eval(&gen) end
#def_single_delegators(accessor, *methods) Also known as: #def_delegators
Shortcut for defining multiple delegator methods, but with no provision for using a different name. The following two code samples have the same effect:
def_delegators :@records, :size, :<<, :map
def_delegator :@records, :size
def_delegator :@records, :<<
def_delegator :@records, :map
# File 'lib/forwardable.rb', line 269
def def_single_delegators(accessor, *methods) methods.delete("__send__") methods.delete("__id__") for method in methods def_single_delegator(accessor, method) end end
#delegate(hash)
Alias for #single_delegate.
# File 'lib/forwardable.rb', line 289
alias delegate single_delegate
#delegate(method) ⇒ accessor
#delegate([method, method, ...]=> accessor)
Also known as: #delegate
accessor
#delegate([method, method, ...]=> accessor)
Takes a hash as its argument. The key is a symbol or an array of symbols. These symbols correspond to method names. The value is the accessor to which the methods will be delegated.
# File 'lib/forwardable.rb', line 249
def single_delegate(hash) hash.each{ |methods, accessor| methods = [methods] unless methods.respond_to?(:each) methods.each{ |method| def_single_delegator(accessor, method) } } end