Its mostly just esthetics. Java still doesn't support covariant return types
so you cannot override clone() like this...
public interface Element {
public Element clone() {
...
}
}
So clone() must return type Object. This is a shame which makes it a bit
ugly to use...
Element e1 = ...;
Element e2 = (Element) e1.clone();
Also the clone() method throws a checked CloneNotSupportedException. So you
have to do things like this
try {
Element e2 = (Element) e1.clone();
}
catch (CloneNotSupportedException e) {
}
rather than the simpler
Element e2 = e1.createCopy();
createCopy() can take an optional QName or a string for the new element name
as well allowing a clone with a different element name to be made...
Element e3 = e1.createCopy( "foo" );
James
----- Original Message -----
From: "Brain, Jim" <[EMAIL PROTECTED]>
To: "'James Strachan'" <[EMAIL PROTECTED]>; "Brain, Jim"
<[EMAIL PROTECTED]>; "DOM4J Mailing List (E-mail)"
<[EMAIL PROTECTED]>
Sent: Monday, December 03, 2001 3:14 PM
Subject: RE: [dom4j-user] Found the problem with my issue
> I saw that afterI sent the email.
>
> However, if the standard clone call is implemented, why add the
createCopy()
> method. Is there a preference of one over the other?
>
> Jim
>
>
> Jim Brain, [EMAIL PROTECTED]
> "Researching tomorrow's decisions today."
> (319) 369-2070 (work)
> SYSTEMS ARCHITECT, INDIVIDUAL ITS, LIFE INVESTORS INSURANCE COMPANY OF
> AMERICA
>
> -----Original Message-----
> From: James Strachan [mailto:[EMAIL PROTECTED]]
> Sent: Saturday, December 01, 2001 4:17 AM
> To: Brain, Jim; DOM4J Mailing List (E-mail)
> Subject: Re: [dom4j-user] Found the problem with my issue
>
> You can call clone() if you wish.
>
> Element e1 = ...;
> Element e2 = (Element) e1.clone();
>
> Node implements Cloneable. If you look at the Interface Hierarchy this
might
> make more sense...
>
> http://dom4j.org/apidocs/org/dom4j/package-tree.html
>
> James
> ----- Original Message -----
> From: "Brain, Jim" <[EMAIL PROTECTED]>
> To: "DOM4J Mailing List (E-mail)" <[EMAIL PROTECTED]>
> Sent: Friday, November 30, 2001 7:49 PM
> Subject: [dom4j-user] Found the problem with my issue
>
>
> > Re: the issue I was having with returning an element from a class
through
> a
> > classloader, etc.
> >
> > As James surmised, the classloader was not the issue.
> >
> > The issue was:
> >
> > I created a class T:
> >
> > Class T
> > Element _e;
> >
> > Element getE()
> > { return _e; }
> >
> > void setE(Element e) {
> > _e=e;
> > }
> > }
> >
> > That did not work when I called getE to get the element, so I changed
the
> > setE to be:
> >
> > return e.detach();
> >
> > that worked until I invoked the Class.forName to load the T class... I
> > thought.
> >
> > So, I changed getE to be:
> >
> > Document d=DocumentHelper.newDocument();
> > d.setRootElement(_e);
> > return d.getRootElement().detach()
> >
> > which looked like it worked.
> >
> > In any case, the classloader was just hiding the issue. The real issue
> was
> > that I was calling T.getE() in my test code, and the second call failed,
> > because _e had been attached to a document in the first part of my test.
> I
> > changed the code to be:
> >
> > Element getE()
> > { return e.createCopy("Name"); }
> >
> > void setE(Element e)
> > { _e=e.createCopy("name); }
> >
> > Now, all works. Yay!
> >
> > However, this brings up a couple of questions:
> >
> > Since element subs fom Object, can't I use use clone()? Or, since there
> is
> > obviously a new API, why wasn;t clone overridden?
> > As well, is there a method on Element that is createCopy()? I want the
> same
> > localname (I think). Why do I need to give a new name?
> >
> > Jim
> >
> >
> >
> >
> >
> > Jim Brain, [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
> > "Researching tomorrow's decisions today."
> > (319) 369-2070 (work)
> > Systems Architect, Individual ITS, Life Investors Insurance Company of
> > America
> >
> >
> > _______________________________________________
> > dom4j-user mailing list
> > [EMAIL PROTECTED]
> > https://lists.sourceforge.net/lists/listinfo/dom4j-user
> >
>
>
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