On Tue, 20 May 2003, Jacob Kjome wrote:
>
> Hi Arno,
>
> Your response was very informative!
>
> Looks like the package switch from dom.html to dom.html2 came between the
> following releases...
>
> http://www.w3.org/TR/2001/WD-DOM-Level-2-HTML-20011210/java-binding.html
> and
> http://www.w3.org/TR/2002/CR-DOM-Level-2-HTML-20020605/java-binding.html
>
>
> So, where is the source being kept for xmlParserAPIs.jar and xml-apis.jar
> because it doesn't exist any longer in the Xerces2-j source. Are these
> just API's which are collected from external sources where the standards
> are stored....as of Xerces-2.4.0? And how is xml-apis.jar different from
> xmlParserAPIs.jar? Why have both?
XML APIs such as DOM, SAX are now extracted from the xml-commons project
when compiling Xerces. You can view the source here:
http://cvs.apache.org/viewcvs.cgi/xml-commons/java/external/src/. Thus
Xerces no longer maintains copies of these sources. The purpose of
xml-commons is to share common code across proejcts, so Xalan and other
projects should come packaged with the same (synched up) APIs.
xmlParserAPIs.jar and xml-apis.jar are the same package. The name of the
second package is just a naming convention that I believe Xalan and other
projects use. The first package name is deprecated though I don't think
that's mentioned in the Xerces documentation. Keeping the former name
around prevents people from having to change environment variables, etc.
> A further question. Since Xerces2 seems to be doing the "correct" thing in
> distributing only the original html dom level1 standard interfaces rather
> than the level2, it seems that consumers of the interfaces ought to fall
> into line with the original standard, if possible. To that end, what is
> the appropriate change to make to the following code...
>
> optionElement.setSelected(selectionModel.isSelectedIndex(i));
>
>
> would it be?.....
>
> if (selectionModel.isSelectedIndex(i))
> optionElement.setAttribute("selected", "selected");
> else optionElement.removeAttribute("selected");
>
>
> Or is there another way?
>
> I based this on the following implementation of setAttribute() in
> org.apache.html.dom.HTMLElementImpl.java
>
> void setAttribute( String name, boolean value )
> {
> if ( value )
> setAttribute( name, name );
> else
> removeAttribute( name );
> }
>
> BTW, the javadoc for that seems to be incorrect. It claims "If the value
> is true, the attribute is set to an empty string". That is, obviously, not
> the case. If the value is true, the attribute value is set to the value of
> the "name" parameter, which is the same as the attribute name. So, instead
> of <option selected ...>, as the javadoc seems to claim, it would be
> <option selected="selected" ...>. I'm actually not complaining about the
> behavior (I don't want that to change), I'm just saying that javadoc should
> be corrected to state what actually happens.
>
> thanks,
>
> Jake
>
> At 01:37 PM 5/20/2003 +0200, Arno Schatz wrote:
> >Hi Jake,
> >
> >The problem is that the HTML DOM Level 2 early Working drafts changed the
> >API of some HTMLElements, but not the package names (see
> >http://www.w3.org/TR/2000/WD-DOM-Level-2-HTML-20001113/java-binding.html).
> >Before the final recommendation the package names where changed to
> >org.w3c.dom.html2, thus ending the confusion about incompatibility.
> >
> >The source of the problem is that people were using the interfaces from
> >those early Level 2 interfaces and getting into compatibility issues. This
> >poped up again on the Xerces-J developer list when Neeraj discovered
> >incompatibilities with JDK1.4, because JDK1.4 ships with such an early
> >Level 2 api (having the old package name, but some new methods). See
> >thread 'Xerces DOM HTML impl' on the developer list.
> >
> >Since, the HTML DOM implementation provided by Xerces is really DOM Level
> >1, they are shipping the 'real' DOM Level 1 API with Xerces. However, this
> >may result in some tricky classpath issues if you are using JDK1.4, since
> >the Xerces classes don't provide the additional methods found in JDK1.4
> >(HTML DOM Level 2) but not present in the original HTML DOM Level 1 API.
> >
> >I also think the only clean solution is to use HTML DOM Level 1 API or
> >provide a DOM Level 2 Implementation, but then use the final
> >recommendation with the new package names. Then you won't have any
> >incompatibilities any more. (But AFAIK, there is no Level 2 implementation
> >out there :-( ).
> >
> >Also another point to mention is that HTML DOM Level 2 is based on DOM
> >Level 2 Core, while Level 1 is based on, you guessed it, Core DOM Level
> >1. So if you are using Xerces 2, you will use DOM Core Level 2 + HTML DOM
> >Level 1. This seems to works ok. I just found some performance drawbacks,
> >for example, HTMLDOcument implements the 'getElementById' method in a very
> >slow fashion (searching the tree every time). This method is provided
> >in class Document since Level 2 (and implemented by Xerces as Hashtable
> >lookup).
> >
> >hope that helps,
> > Arno
> >
> >
> >Jacob Kjome wrote:
> >>Hello,
> >>I ran into a very strange issue when using the org.w3c.dom.html
> >>interfaces in the release versions of Xerces2 (tried 2.3.0 and 2.4.0).
> >>The binaries of the xmlParserAPIs.jar and xml-apis.jar both seem to
> >>contain a different version of the html dom interfaces than what comes in
> >>the source. For instance, in the Xerces-J-src.2.3.0.zip download, when I
> >>browse to org.w3c.dom.html.HTMLOptionElement.java, said file contains the
> >>method setSelected(boolean). However, when I grab the class file from
> >>the binary release (Xerces-J-bin.2.3.0.zip) it HTMLOptionElement does not
> >>contain that method. What gives here?
> >>Another very confusing thing is the source download for the 2.4.0
> >>distribution (Xerces-J-src.2.4.0.zip) contains only a single file in the
> >>org.w3c.dom.html package ( HTMLDOMImplementation.java ). Where are
> >>rest? Well, maybe in the xml-apis--src.zip that comes in the
> >>Xerces-J-tools.2.4.0.zip download. Is that right? Well, the problem
> >>here is that the w3c htm dom being used there is based on the original
> >>html dom 1 source released back in 1998. HTMLOptionElement did not have
> >>the setSelected(boolean), only getSelected(). But anyone who has used
> >>Xerces-1 has already been used to using newer dom interfaces with
> >>setSelected(boolean) in HTMLOptionElement.
> >>Can anyone clear this up?
> >>1. Why has Xerces2 reverted to an older version of the dom interfaces
> >>than Xerces1 had?
> >>2. Why does the source download for Xerces 2.3.0 come with newer
> >>versions of the dom interfaces than is released in the 2.3.0 binaries (or
> >>any of the Xerces2 binaries, for that matter)? And why does the source
> >>download for Xerces 2.4.0 not have these newer sources anymore?
> >>3. Where did these newer sources come from anyway? After the html DOM1
> >>release, all work was done on the html DOM2 release,. but that falls
> >>under a different package named org.w3c.dom.html2.
> >>
> >>Curiously enough, if I extract the org.w3c.dom.html package from the
> >>Xerces 2.3.0 source distribution, compile the interfaces, jar the
> >>interfaces, and put the jar in my build classpath, everything compiles
> >>just fine.
> >>extremely confused,
> >>Jake
> >>
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