Re: Accessibility of suBclass-fields from suPERclass (reflection)

From:

Eric Sosman <esosman@comcast-dot-net.invalid>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 16 Aug 2014 20:22:16 -0400

Message-ID:

<lsosjs$gtc$1@dont-email.me>

On 8/16/2014 6:37 PM, Andreas Leitgeb wrote:

Robert Klemme <shortcutter@googlemail.com> wrote:

On 16.08.2014 10:46, Andreas Leitgeb wrote:

I'm not complaining about that extra setAccessibility(true), I just
would like to see an example of where a Base-class accessing its children
could be a security issue. I'm not talking of some arbitrary class
attempting access, but about the target class's parent (or grandparent)
class.

If you want a superclass to access subclass state you need to provide
means for it, e.g. defining abstract accessor or other methods in the
base class which then must be implemented in subclasses.

I'll describe my situation a bit:

I have a special Base class, and each of its subclasses serve exactly
one purpose: a collection of name/value associations where the java-
compiler knows about the valid names, so as to detect accesses to
non-existing names already at compile-time. (without that last premise,
I would have used HashMaps instead of subclasses)

Would an EnumMap serve?

Overall-operations, (e.g. resetting all values of a given subclass
instance) are done from Base-class by use of reflection.

Why by reflection? Why not by a reset() method, abstract in
the superclass?

I'm confident you have reasons, but I'm sure I haven't yet
grasped them.

--
esosman@comcast-dot-net.invalid