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  • delegate.rb

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Delegator

Delegator is an abstract class used to build delegator pattern objects from subclasses. Subclasses should redefine _getobj_. For a concrete implementation, see SimpleDelegator.

Constants

IgnoreBacktracePat

Public Class Methods

new(obj) click to toggle source

Pass in the obj to delegate method calls to. All methods supported by obj will be delegated to.

 
               # File delegate.rb, line 124
  def initialize(obj)
    preserved = ::Kernel.public_instance_methods(false)
    preserved -= ["to_s","to_a","inspect","==","=~","==="]
    for t in self.class.ancestors
      preserved |= t.public_instance_methods(false)
      preserved |= t.private_instance_methods(false)
      preserved |= t.protected_instance_methods(false)
      break if t == Delegator
    end
    preserved << "singleton_method_added"
    for method in obj.methods
      next if preserved.include? method
      begin
        eval "          def self.#{method}(*args, &block)
            begin
              __getobj__.__send__(:#{method}, *args, &block)
            ensure
              $@.delete_if{|s|IgnoreBacktracePat=~s} if $@
            end
          end
", nil, __FILE__, __LINE__+1
      rescue SyntaxError
        raise NameError, "invalid identifier %s" % method, caller(4)
      end
    end
  end
            

Public Instance Methods

__getobj__() click to toggle source

This method must be overridden by subclasses and should return the object method calls are being delegated to.

 
               # File delegate.rb, line 175
def __getobj__
  raise NotImplementedError, "need to define `__getobj__'"
end
            
marshal_dump() click to toggle source

Serialization support for the object returned by _getobj_.

 
               # File delegate.rb, line 180
def marshal_dump
  __getobj__
end
            
marshal_load(obj) click to toggle source

Reinitializes delegation from a serialized object.

 
               # File delegate.rb, line 184
def marshal_load(obj)
  initialize_methods(obj)
  __setobj__(obj)
end
            
method_missing(m, *args, &block) click to toggle source

Handles the magic of delegation through _getobj_.

 
               # File delegate.rb, line 154
def method_missing(m, *args, &block)
  target = self.__getobj__
  unless target.respond_to?(m)
    super(m, *args, &block)
  end
  target.__send__(m, *args, &block)
end
            
respond_to?(m, include_private = false) click to toggle source

Checks for a method provided by this the delegate object by fowarding the call through _getobj_.

 
               # File delegate.rb, line 166
def respond_to?(m, include_private = false)
  return true if super
  return self.__getobj__.respond_to?(m, include_private)
end
            

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