[jdom-interest] Child-Parent patch - Ideas.
jhunter at xquery.com
Thu Feb 5 14:41:29 PST 2004
Rolf sent in this change a while back, and I just integrated it with the
latest CVS code but haven't checked it in. I'm curious what other
people think of it as an approach. Rolf's description below explains
I invite people to compare the CVS HEAD (get it from CVS or at
http://jdom.org/head.zip) versus the source at http://jdom.org/rolf.zip.
Comments welcome. Which way should we go?
Rolf Lear wrote:
> I have had a look at the Child/Parent thing.
> Personally, I don't think the Idea has been taken far enough, so I
> played around with the concept, and "normalised" some of the redundancies.
> Firstly, I converted the Child interface into an Abstract class that
> deals with ALL Parent/child relationships for the Child role, including
> detaching, cloning, set/getParent (and holds the parent instance field).
> I also implemented getDocument at the Child Class level (all children
> have the same mechanism for getting the Document).
> Next, I added the method "getDocument" to the Parent Interface... and
> parent can getDocument, including the Document class which has "return
> this;" in the getDocument().
> Finally, I changed the ContentList class substantially. elementData is
> now called childData, and is of type Child instead of Object. The
> ContentList owner is now of type Parent instead of Object. I have added
> a method canContain to the Parent interface, and thus the actual Parent
> object determines what content is allowed in the contentlist, so instead
> of add(int,Text), add(int,Element), add(int,CDATA),
> add(int,ProcessingInstruction), etc, there is just add(int, Child).
> In doing all of the above, I have cut large amounts of
> redundant/duplicated code, simplified the relationships, and thrown away
> "special cases". The only downside I can see in terms of "functionality"
> is that some of the exceptions are thrown with less specialised messages...
> Please have a look, and comment on the concept. Note, that this is only
> possible by converting Child to an abstract class instead of an interface.
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