Module: Jinx::Inversible

Included in:
Resource
Defined in:
lib/jinx/resource/inversible.rb

Overview

Resource inverse integrity aspect mix-in. The Inversible methods are intended for the sole use of the Inverse class mix-in.

Instance Method Summary collapse

Instance Method Details

#add_to_inverse_collection(newval, accessors, inverse) { ... } ⇒ Object

Sets a collection attribute value in a way which enforces inverse integrity. The inverse of the attribute is a collection accessed by calling inverse on newval.

Parameters:

  • newval (Resource) —

    the new attribute reference value

  • accessors ((Symbol, Symbol)) —

    the reader and writer to use in setting the attribute

  • inverse (Symbol) —

    the inverse collection attribute to which this domain object will be added

Yields:

  • a factory to create a new collection on demand (default is an Array)



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# File 'lib/jinx/resource/inversible.rb', line 60

def add_to_inverse_collection(newval, accessors, inverse)
  rdr, wtr = accessors
  # the current inverse
  oldval = send(rdr)
  # no-op if no change
  return newval if newval == oldval

  # delete self from the current inverse reference collection
  if oldval then
    coll = oldval.send(inverse)
    coll.delete(self) if coll
  end
  
  # call the writer on this object
  send(wtr, newval)
  
  # add self to the inverse collection
  if newval then
    coll = newval.send(inverse)
    if coll.nil? then
      coll = block_given? ? yield : Array.new
      newval.set_property_value(inverse, coll)
    end
    coll << self
    if oldval then
      logger.debug { "Moved #{qp} from #{rdr} #{oldval.qp} #{inverse} to #{newval.qp}." }
    else
      logger.debug { "Added #{qp} to #{rdr} #{newval.qp} #{inverse}." }
    end
  end
  
  newval
end

#set_inverse(other, writer, inv_writer) ⇒ Object

Sets an attribute inverse by calling the attribute writer method with the other argument. If other is non-nil, then the inverse writer method is called on self.

Parameters:

  • other (Resource) —

    the attribute value to set

  • writer (Symbol) —

    the attribute writer method

  • inv_writer (Symbol) —

    the attribute inverse writer method defined for the other object



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# File 'lib/jinx/resource/inversible.rb', line 12

def set_inverse(other, writer, inv_writer)
  other.send(inv_writer, self) if other
  send(writer, other)
end

#set_inversible_noncollection_attribute(newval, accessors, inverse_writer) ⇒ Object

Sets a non-collection attribute value in a way which enforces inverse integrity.

Parameters:

  • newval (Object) —

    the value to set

  • accessors ((Symbol, Symbol)) —

    the reader and writer methods to use in setting the attribute

  • inverse_writer (Symbol) —

    the inverse attribute writer method



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# File 'lib/jinx/resource/inversible.rb', line 24

def set_inversible_noncollection_attribute(newval, accessors, inverse_writer)
  rdr, wtr = accessors
  # the previous value
  oldval = send(rdr)
  # bail if no change
  return newval if newval.equal?(oldval)

  # clear the previous inverse
  logger.debug { "Moving #{qp} from #{oldval.qp} to #{newval.qp}..." } if oldval and newval
  if oldval then
    clr_wtr = self.class === oldval && oldval.send(rdr).equal?(self) ? wtr : inverse_writer
    oldval.send(clr_wtr, nil)
  end
  
  # call the writer
  send(wtr, newval)
  
  # call the inverse writer on self
  if newval then
    newval.send(inverse_writer, self)
    logger.debug { "Moved #{qp} from #{oldval.qp} to #{newval.qp}." } if oldval
  end
  
  newval
end