/// <summary>
/// Gives the collection of "xmlns" attributes of the "rdf:RDF" root node
/// </summary>
internal static XmlAttributeCollection GetXmlnsNamespaces(XmlNode rdfRDF, XmlNamespaceManager nsMgr)
{
XmlAttributeCollection xmlns = rdfRDF.Attributes;
if (xmlns != null && xmlns.Count > 0)
{
IEnumerator iEnum = xmlns.GetEnumerator();
while (iEnum != null && iEnum.MoveNext())
{
XmlAttribute attr = (XmlAttribute)iEnum.Current;
if (attr.LocalName.ToUpperInvariant() != "XMLNS")
{
//Try to resolve the current namespace against the namespace register;
//if not resolved, create new namespace with scope limited to actual node
RDFNamespace ns =
(RDFNamespaceRegister.GetByPrefix(attr.LocalName) ??
RDFNamespaceRegister.GetByNamespace(attr.Value) ??
new RDFNamespace(attr.LocalName, attr.Value));
nsMgr.AddNamespace(ns.Prefix, ns.Namespace.ToString());
}
}
}
return(xmlns);
}
/// <summary>
/// Finds if the given token contains a recognizable namespace and, if so, abbreviates it with its prefix.
/// It also prepares the result in a format useful for serialization.
/// </summary>
internal static String AbbreviateNamespace(String token)
{
//Null or Space token: it's a trick, give empty result
if (token == null || token.Trim() == String.Empty)
{
return(String.Empty);
}
//Blank token: abbreviate it with "_"
if (token.StartsWith("bnode:"))
{
return(token.Replace("bnode:", "_:"));
}
//Prefixed token: check if it starts with a known prefix, if so just return it
if (RDFNamespaceRegister.GetByPrefix(token.Split(':')[0]) != null)
{
return(token);
}
//Uri token: search a known namespace, if found replace it with its prefix
String tokenBackup = token;
Boolean abbrev = false;
RDFNamespaceRegister.Instance.Register.ForEach(ns => {
if (!abbrev)
{
String nS = ns.ToString();
if (!token.Equals(nS, StringComparison.OrdinalIgnoreCase))
{
if (token.StartsWith(nS))
{
token = token.Replace(nS, ns.NamespacePrefix + ":").TrimEnd(new Char[] { '/' });
//Accept the abbreviation only if it has generated a valid XSD QName
try {
var qn = new RDFTypedLiteral(token, RDFModelEnums.RDFDatatypes.XSD_QNAME);
abbrev = true;
}
catch {
token = tokenBackup;
abbrev = false;
}
}
}
}
});
//Search done, let's analyze results:
if (abbrev)
{
return(token); //token is a relative or a blank uri
}
if (token.Contains("^^")) //token is a typedLiteral absolute uri
{
return(token.Replace("^^", "^^<") + ">");
}
return("<" + token + ">"); //token is an absolute uri
}
