Exception: NRSER::AbstractMethodError

Inherits:
NotImplementedError
  • Object
show all
Defined in:
lib/nrser/errors.rb

Overview

Extension of Ruby’s NotImplementedError to provide a useful message and convenient constructor for abstract methods.

Examples:


def f
  raise NRSER::AbstractMethodError.new( self, __method__ )

Instance Method Summary collapse

Constructor Details

#initialize(instance, method_name) ⇒ AbstractMethodError

Construct a new ‘AbstractMethodError`.

Parameters:

  • instance (Object) —

    Instance that invoked the abstract method.

  • method_name (Symbol | String) —

    Name of abstract method.



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# File 'lib/nrser/errors.rb', line 27

def initialize instance, method_name
  @instance = instance
  @method_name = method_name
  @method = instance.method @method_name
  
  message = if @method.owner == instance.class
    NRSER.dedent <<-END
      Method #{ @method.owner.name }##{ @method_name } is abstract, meaning 
      #{ @method.owner.name } is an abstract class and the invoking 
      instance #{ @instance } should NOT have been constructed.
    END
  else
    NRSER.squish <<-END
      Method #{ @method.owner.name }##{ @method_name } is abstract and 
      has not been implemented in invoking class #{ @instance.class }.
      
      If you *are* developing the invoking class #{ @instance.class } it
      (or a parent class between it and #{ @method.owner.name }) must 
      implement ##{ @method_name }.
      
      If you *are not* developing #{ @instance.class } it should be treated
      as an abstract base class and should NOT be constructed. You need to
      find a subclass of #{ @instance.class } to instantiate or write 
      your own.
    END
  end
  
  super message
end