Re: [morph-developer] InstantiatingReflector

[Matt B. <gud...@ya...>]

I am reawakening this thread.  I touched on this
subject during the original discussion, but at the
time I couldn't quite articulate what was bothering me
about the whole business.  Last Friday it burst upon
me, and I have continued to kick it around over the
weekend but have not been able to refute my own logic:

Basically with InstantiatingReflector taking a source
parameter, it IS a converter.  What is the difference
between:

InstantiatingReflector.newInstance(Class, Object)
-and-
DecoratedConverter.convert(Class, Object)
?

>From my POV, nothing.  Different semantics for what,
using the method parameters as an indicator, is one
concept.  The role of the InstantiatingReflector in
the Morph library is to adapt a copier to the
converter interface, using the following algorithm:

1. Create a new instance I
2. Invoke copy() using I as the destination object.

This sequence of operations amounts to a "derived
conversion":  one which relies on a parent conversion
to supply the target object, then modifies the
resulting object.  This modification will always
consist of making changes on a target object based on
the source object (otherwise the parent converter
alone would suffice), and thus infallibly corresponds
in intent with Copier.copy().  This proves that a
DerivedConverter is precisely a Copier that implements
Converter by first delegating to a parent Converter,
then copies the source to the resulting destination
object.  The parent converter can be overridden, but
would default to an, e.g., NewInstanceConverter which
simply creates a new instance of the destinationClass.

In adopting the DerivedConverter concept,
InstantiatingReflector would, in my opinion, no longer
be needed, and would hopefully be deprecated and then
removed as soon as the current players on the mailing
list(s) are all up to speed.  Because the interfaces
are so similar, I would expect the refactoring of a
custom InstantiatingReflector implementation to a
custom Converter implementation to be trivial.

I invite discussion, but I really think I have
something here.

Impatiently awaiting comment,
Matt B


 
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