public function add_triple($s, $p, $o, $o_type = null)
{
//skip triple with empty subject, predicate or object
if (!isset($s) || !isset($p) || !isset($o)) {
return;
}
$this->number_of_triples++;
//detect object type in case it was not provided
if (empty($o_type)) {
if (RdfStream::is_uri($o)) {
$o_type = RdfStream::RDF_URI;
} else {
if (is_int($o)) {
$o_type = RdfStream::RDF_INTEGER;
} else {
if (stristr($p, "date") >= 0 && ($date = RdfStream::get_xsddatetime($o))) {
if (strlen($date) > 10) {
$o_type = RdfStream::RDF_DATETIME;
} else {
$o_type = RdfStream::RDF_DATE;
}
$o = $date;
} else {
$o_type = RdfStream::RDF_STRING;
}
}
}
}
switch ($this->output) {
case RdfStream::RDF_SYNTAX_NT:
$this->nt_add_triple($s, $p, $o, $o_type);
break;
case RdfStream::RDF_SYNTAX_RDFXML:
default:
$this->rdfxml_add_triple($s, $p, $o, $o_type);
break;
}
}
