/**
* Serialize the given SMWExpData object, possibly recursively with
* increased indentation.
*
* @param $data SMWExpData containing the data to be serialised.
* @param $indent string specifying a prefix for indentation (usually a sequence of tabs)
*/
protected function serializeNestedExpData(SMWExpData $data, $indent)
{
if (count($data->getProperties()) == 0) {
return;
// nothing to export
}
// Avoid posting turtle property declarations already known for the
// subject more than once
if ($data->getSubject()->getDataItem() !== null && $data->getSubject()->getDataItem()->getNamespace() === SMW_NS_PROPERTY) {
$hash = $data->getHash();
$poolCache = InMemoryPoolCache::getInstance()->getPoolCacheFor('turtle.serializer');
if ($poolCache->contains($hash) && $poolCache->fetch($hash)) {
return;
}
$poolCache->save($hash, true);
}
$this->recordDeclarationTypes($data);
$bnode = false;
$this->post_ns_buffer .= $indent;
if (!$data->getSubject()->isBlankNode()) {
$this->serializeExpResource($data->getSubject());
} else {
// blank node
$bnode = true;
$this->post_ns_buffer .= "[";
}
if ($indent !== '' && !$bnode) {
// called to generate a nested descripion; but Turtle cannot nest non-bnode descriptions, do this later
$this->subexpdata[] = $data;
return;
} elseif (!$bnode) {
$this->post_ns_buffer .= "\n ";
}
$firstproperty = true;
foreach ($data->getProperties() as $property) {
$this->post_ns_buffer .= $firstproperty ? "\t" : " ;\n {$indent}\t";
$firstproperty = false;
$prop_decl_queued = false;
$class_type_prop = $this->isOWLClassTypeProperty($property);
$this->serializeExpResource($property);
$firstvalue = true;
foreach ($data->getValues($property) as $value) {
$this->post_ns_buffer .= $firstvalue ? ' ' : ' , ';
$firstvalue = false;
if ($value instanceof SMWExpLiteral) {
$prop_decl_type = SMW_SERIALIZER_DECL_APROP;
$this->serializeExpLiteral($value);
} elseif ($value instanceof SMWExpResource) {
$prop_decl_type = SMW_SERIALIZER_DECL_OPROP;
$this->serializeExpResource($value);
} elseif ($value instanceof SMWExpData) {
// resource (maybe blank node), could have subdescriptions
$prop_decl_type = SMW_SERIALIZER_DECL_OPROP;
$collection = $value->getCollection();
if ($collection !== false) {
// RDF-style collection (list)
$this->post_ns_buffer .= "( ";
foreach ($collection as $subvalue) {
$this->serializeNestedExpData($subvalue, $indent . "\t\t");
if ($class_type_prop) {
$this->requireDeclaration($subvalue->getSubject(), SMW_SERIALIZER_DECL_CLASS);
}
}
$this->post_ns_buffer .= " )";
} else {
if ($class_type_prop) {
$this->requireDeclaration($value->getSubject(), SMW_SERIALIZER_DECL_CLASS);
}
if (count($value->getProperties()) > 0) {
// resource with data: serialise
$this->post_ns_buffer .= "\n";
$this->serializeNestedExpData($value, $indent . "\t\t");
} else {
// resource without data: may need to be queued
$this->serializeExpResource($value->getSubject());
}
}
}
if (!$prop_decl_queued) {
$this->requireDeclaration($property, $prop_decl_type);
$prop_decl_queued = true;
}
}
}
$this->post_ns_buffer .= ($bnode ? " ]" : " .") . ($indent === '' ? "\n\n" : '');
}
