/**
* Short description of method getRdfTriples
*
* @access public
* @author Joel Bout, <*****@*****.**>
* @param Resource resource
* @return \core_kernel_classes_ContainerCollection
*/
public function getRdfTriples(\core_kernel_classes_Resource $resource)
{
$returnValue = null;
$returnValue = new \core_kernel_classes_ContainerCollection(new \common_Object(__METHOD__));
$referencer = ResourceReferencer::singleton();
$tableName = $referencer->resourceLocation($resource);
if (!empty($tableName)) {
try {
$tblmgr = new TableManager($tableName);
$propertiesTableName = $tblmgr->getPropertiesTable();
$dbWrapper = \core_kernel_classes_DbWrapper::singleton();
// We get the triples for cardinality = multiple or lg dependent properties
// as usual...
$quotedUri = $dbWrapper->quote($resource->getUri());
$propsQuery = 'SELECT "b"."id", "b"."uri", "p"."property_uri" AS "property_uri", COALESCE("p"."property_value", "p"."property_foreign_uri") as "property_value", "p"."l_language" FROM "' . $tableName . '" "b" ';
$propsQuery .= 'INNER JOIN "' . $propertiesTableName . '" "p" ON ("b"."id" = "p"."instance_id") WHERE "b"."uri" = ' . $quotedUri;
$propertyColumns = $tblmgr->getPropertyColumns();
$baseQuery = '';
if (!empty($propertyColumns)) {
// But if we have properties as columns in the 'base table' we
// have to be crafty...
$baseQueries = array();
foreach ($propertyColumns as $k => $pC) {
$quotedPropUri = $dbWrapper->quote($pC);
$baseQueries[] = 'SELECT "b"."id", "b"."uri", ' . $quotedPropUri . ' AS "property_uri", "b"."' . $k . '" AS "property_value", \'\' AS "l_language" FROM "' . $tableName . '" "b" WHERE "b"."uri" = ' . $quotedUri . ' AND "b"."' . $k . '" IS NOT NULL';
}
$baseQuery = implode(' UNION ', $baseQueries);
}
$query = $propsQuery . ' UNION ' . $baseQuery . ' ORDER BY "property_uri"';
try {
$result = $dbWrapper->query($query);
while ($row = $result->fetch()) {
if ($row['property_value'] != null) {
$triple = new \core_kernel_classes_Triple();
$triple->subject = $row['uri'];
$triple->predicate = $row['property_uri'];
$triple->object = $row['property_value'];
$triple->lg = $row['l_language'];
$returnValue->add($triple);
}
}
// In hard mode, the rdf:type given to resources is defined by
// 'the table' their are belonging to. In this case, we need to
// manually add these triples to the end result.
$types = $resource->getTypes();
foreach ($types as $class) {
$triple = new \core_kernel_classes_Triple();
$triple->subject = $resource->getUri();
$triple->predicate = RDF_TYPE;
$triple->object = $class->getUri();
$triple->lg = '';
$returnValue->add($triple);
}
} catch (\PDOException $e) {
$uri = $resource->getUri();
throw new Exception("Unable to retrieve RDF triples of resource '{$uri}': " . $e->getMessage());
}
} catch (HardapiException $e) {
throw new Exception("Unable to access data from table '{$tableName}: " . $e->getMessage());
}
}
return $returnValue;
}
