Re: JDOM and memory

It may be useful to compare and contrast with XOM?

http://xom.nu/designprinciples.xhtml#d0e389

On Mon, Jan 23, 2012 at 9:04 AM, Rolf Lear wrote:

>
> Heh... you are right.
>
> Element should not be List<Content>, and the getContent() method can
> create a dynamic implementation as needed. That's the solution... Element
> already has rules about synchronization so multiple 'active' dynamic
> instances should not be a problem....
>
> Thanks. I will play with that concept.
>
> Rolf
>
> On Mon, 23 Jan 2012 16:59:35 +0000, Michael Kay <[email protected]> wrote:
> > On 23/01/2012 16:28, Rolf Lear wrote:
> >> Hi all.
> >>
> >> I have started on this memory optimization, and it is still in early
> >> stages. There is one API issue though:
> >>
> >> The Element API has the two methods:
> >>
> >> addContent(Content node)
> >> addContent(Collection<? extends Content>  newContent)
> >>
> >> if I make Element implement List<Content>  (which is what this
> >> memory-change will do), then the above two methods become ambiguous
> >> because
> >> Element will be both Content and List<Content>
> > And that suggests to me that it is a bad idea.
> >
> > The class hierarchy should reflect "is-a" relationships, it shouldn't be
>
> > designed to tweak performance. It's not true that an Element and its
> > contents are the same thing, therefore it's wrong to treat them as being
>
> > the same object. It will only lead to confusion.
> >
> > You can achieve the memory saving by having Element.getChildren() create
>
> > the returned List object dynamically (it doesn't need to copy any data
> > to achieve this).
> >
> >  > The logical thing to do would be to deprecate addContent(Collection)
> >
> > I don't think that solves the problem. There will be cases where
> > existing code fixes up to the wrong method, and ends up adding the
> > children of an element to a new parent rather than adding the element
> > itself.
> >
> > Michael Kay
> > Saxonica
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