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SiRPAC feedback: literal valued versus resource valued statements

From: Dan Brickley <Daniel.Brickley@Bristol.ac.uk>
Date: Wed, 10 Feb 1999 18:42:41 +0000 (GMT)
To: www-rdf-comments@w3.org
Message-ID: <Pine.GHP.4.02A.9902101832250.3094-100000@mail.ilrt.bris.ac.uk>

Hi Janne (and others),

I've been trying to figure out how SiRPAC distinguishes between RDF
statements where the value is a literal (such as a string) versus cases
where the value is another resource identified by URI. This distinction
does not seem to be evident in the triples-oriented output format, ie.
triple("aaa","bbb","ccc")   isn't enough to tell you whether to treat
"ccc" as a resource identifier or a string.

The class org.w3c.rdf.Triple in SiRPAC v1.8 is defined as follows:

public class Triple
  private String        m_sPredicate = null;
  private String        m_sSubject = null;
  private String        m_sObject = null;

   * The parameters to constructor are in the following format
   * Predicate, Subject, Object
  public Triple (String sPredicate, String sSubject, String sObject) {
    m_sPredicate = sPredicate;
    m_sSubject = sSubject;
    m_sObject = sObject;

  public String predicate () {
    return m_sPredicate;

  public String subject () {
    return m_sSubject;

  public String object () {
    return m_sObject;

...and again this doesn't make the distinction. I'm trying to plumb
SiRPAC into a system with an API along lines of

RDFGraph db = new RDFGraph();
db.assert( Resource, Property, Value, VAL_TYPE) 

...and don't seem to be  able to get the appropriate info from SiRPAC
without string inspection / heuristics for guessing the value type.

Am I missing something in another class which would help?

I'm sending this to rdf-comments as I guess it is something we'll
need to think about if we want to do interoperability testing of



Institute for Learning and Research Technology http://www.ilrt.bris.ac.uk/
University of Bristol,  Bristol BS8 1TN, UK.   phone:+44(0)117-9288478
Received on Wednesday, 10 February 1999 13:42:49 UTC

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