XOM API for Processing XML with Java

[jcowan AT reutershealth.com]

Elliotte Rusty Harold scripsit:

> Can you explain why you think checkDetach() is necessary for this 
> use-case? It's not obvious to me.

Well, within a single package of XOM subclasses, it's redundant
to have checkAttach and checkDetach, because you can always use
the double-dispatch pattern: the parent can ask the child via a
package-private interface "Do you want to be attached to/detached
from me?"  Where it gets important is when multiple packages are trying
to interact, since the parent has no way to get the child's input on
the subject.  In addition, if you subclass Comment, PI, or Text, then
checkAttach/checkDetach is the only way for any of them to get into
the act.  But I find it hard to imagine that anyone would care.

I agree that if you're only going to keep one, you should keep the parent
check, since typically parents care more about who their children are
than vice versa.

-- 
BALIN FUNDINUL          UZBAD KHAZADDUMU        jcowan AT reutershealth.com
BALIN SON OF FUNDIN     LORD OF KHAZAD-DUM      http://www.ccil.org/~cowan