Hi Claude,
Thanks for your guidance - it worked nicely.
I made a couple of changes to make it as I wanted:
1) Need to sort using the name of the subject resources,
not the resource itself. Have to build a map to do that
2) Need to take iterator in descending order after sort,
to have the named resources come up first
The changed & tested code:
-------------------------------------------------------------------
public void writeRDFStatements(Model model, PrintWriter writer) {
Map<String, Resource> subjMap = new HashMap<String, Resource>();
ResIterator subjIter = model.listSubjects();
while (subjIter.hasNext()) {
Resource subj = subjIter.next();
Resource typeDefn = subj.getPropertyResourceValue(RDF.type);
subjMap.put(subj.toString(), subj);
}
TreeSet<String> subjs = new TreeSet<String>(subjMap.keySet());
Iterator<String> rIter = subjs.descendingIterator();
while (rIter.hasNext())
writeRDFStatements(model, subjMap.get(rIter.next()), writer);
}
-------------------------------------------------------------------
Chan
something like
protected void writeRDFStatements( Model model, PrintWriter writer )
{
Set<Resource> subjects = new TreeSet<Resource>();
subjects.addAll( model.listSubjects().asSet() );
Iterator<Resource> rIter = subjects.iterator()
while (rIter.hasNext()) writeRDFStatements( model, rIter.nex(), writer
);
}
Might do the trick, assuming that you want the statements in "natural"
order and that you don't have so many as to overflow memory.
If you want a different order you could implement a comparator and
pass it
to the TreeSet constructor.
Claude
On Thu, Sep 12, 2013 at 8:09 AM, <[email protected]> wrote:
Hi Claude,
It's close as this code at least group the triples
per subject basis and the "model.write(stream, lang)"
prints out in that manner. Still, there's no explicit
ordering in the subjects (other than the iterator's
own implicit one). Looks like I need to write my own.
Thanks
Chan
The code you are looking for is probably in
com.hp.hpl.jena.xmloutput.**impl.Basic.java
protected void writeRDFStatements( Model model, PrintWriter writer
)
{
ResIterator rIter = model.listSubjects();
while (rIter.hasNext()) writeRDFStatements( model,
rIter.nextResource(),
writer );
}
protected void writeRDFStatements
( Model model, Resource subject, PrintWriter writer )
{
StmtIterator sIter = model.listStatements( subject, null, (RDFNode)
null
);
writeDescriptionHeader( subject, writer );
while (sIter.hasNext()) writePredicate( sIter.nextStatement(),
writer );
writeDescriptionTrailer( subject, writer );
}
However, it just prints the statements out in the order the model
returns
them by listSubjects() and listStatements() for each subject
returned. So
as Chris said the order is model implementation specific.
Claude
On Thu, Sep 12, 2013 at 7:01 AM, <[email protected]> wrote:
On 2013-09-11 23:15, Chris_Dollin wrote:
On Wednesday, September 11, 2013 07:28:33 PM [email protected]
wrote:
Is there a Jena stmt/triple iterator feeding items in order ?
I looked around the Jena API list to find, but no luck. However,
the 'Model.write(outputStream, lang)' method produces triple
listing in hierarchy with indentation - wonder how the method
produces such listing.
Is Model.listStatements() what you're looking for?
[Note: there is no "in order"; the statements come out in some
unspecified implementation-specific order.]
Chris
What I'm looking for is another iterator (or a Jena utility ?)
which can order the triples in hierarchy - not in random sequence
from 'listStatements()'. I just need to traverse a resource from
the top to the bottom, and it'd be nice to have an iterator to feed
the triples that way. The model.write() produces triples in
sequence
and I just want to utilize that ordering mechanism.
Chan
