XOM API for Processing XML with Java

[Wolfgang Hoschek <wolfgang.hoschek AT mac.com>]

That's not a wellformed XML document, hence can't be constructed with  
XOM, hence can't be serialized (whether using bnux or not).
A namespaced element has a qualified name and a namespace URI; the  
latter is missing in your example. Thus, XOM raises an exception even  
before bnux even comes comes into play, probably on

        new Element("gml:featureMember")

Rather, you'd have to construct namespace'd elements like this:

        new Element("gml:featureMember", "http://www.opengis.net/gml";)

Although it's not really necessary you can also add a namespace  
declaration via

        element.addNamespaceDeclaration("gml", "http://www.opengis.net/gml";)

Wolfgang.


On Apr 11, 2006, at 8:37 PM, Galip Aydin wrote:

> Wolfgang,
> Thanks for the reply. I am trying to serialize individual GML  
> fragments
> which do not contain namespace declarations, as following;
> <gml:featureMember>
>  <Entity>
>   <Bus>
>    <location>
>     <gml:Point srsName="null">
>      <gml:coord>
>       <gml:X>-82.3773</gml:X>
>       <gml:Y>28.0804</gml:Y>
>       <gml:Z>1.0</gml:Z>
>      </gml:coord>
>     </gml:Point>
>    </location>
>   </Bus>
>  </Entity>
> </gml:featureMember>
>
> When I use the method described in the samples it gives an error  
> about the
> namespace gml. So what is the best way to convert this XML fragment  
> to bnux?
> Thanks again,
> Galip.
>
>
> ----- Original Message -----
> From: "Wolfgang Hoschek" <wolfgang.hoschek AT mac.com>
> To: "Galip Aydin" <gaydin AT grids.ucs.indiana.edu>
> Cc: <xom-interest AT lists.ibiblio.org>
> Sent: Tuesday, April 11, 2006 11:03 PM
> Subject: Re: [XOM-interest] BNUX Question
>
>
> > On Apr 11, 2006, at 7:49 PM, Galip Aydin wrote:
> >
> > > Hi All
> > > I I am trying to use bnux in a GIS project to compress very  
> > > large  GML
> > > documents. GML documents are XML files with geographic  information
> > > encoded according to OpenGIS standards. However because  of the  
> > > current
> > > architecture I am having trouble using bnux, and I  was wondering if
> > > anybody has a suggestion. Here is the problem:
> > > I am creating GML documents from MySQL ResultSets. There are   
> > > several
> > > namespace declaration at the top of the GML documents and  several
> > > hundred <gml:featureMember> elements. Each featureMember  element is
> > > created using an individual database results. The system  works as
> > > follows: I am retrieving the results from the MySQL  database in a
> > > streaming fashion, for each result creating a  featureMember  
> > > element and
> > > publishing this to a publish/subscribe  messaging system topic. The
> > > client accumulates the results to  construct the whole GML document.
> > > However since each featureMember  element does not contain the  
> > > namespace
> > > declarations I can't use bnux.
> > > Now, is there a way to create a Streaming Serializer Factory by
> > > providing the namespaces once and use it to compress elements of   
> > > that
> > > document as they become available?
> > >
> > > Thanks in advance for any suggestions.
> > > Galip.
> >
> > I'm not sure I understand the problem. On deserialization, bnux   
> > recreates
> > whatever has been given to it before on serialization,  including
> > namespaces. There's no loss of information.
> >
> > It works by feeding normal XOM nodes such as elements into bnux.  
> > Each  XOM
> > element can have namespaces, but it need not. Such namespaces can  be
> > given in the Element constructor and via
> > Element.addNamespaceDeclaration(). In streaming fashion, you'll use a
> > StreamingSerializer obtained from
> > StreamingSerializerFactory.createBinaryXMLSerializer() to write bnux
> > format. There's an example in the javadoc for StreamingSerializer.
> >
> > BTW, you might want to get started with the bin/fire-bnux command   
> > line
> > test tool, converting bnux to and from XML. You might also want   
> > to run
> > the testsuite via "ant download-testdata test-bnux".
> >
> > Wolfgang.
>
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