Get all literal values for a property of the resource
This method will return an empty array if the resource does not has any literal values for that property.
string $property The name of the property (e.g. foaf:name):
string $lang The language to filter by (e.g. en):
array An array of values associated with the property
public function allLiterals($property, $lang = null) {
$this
->checkHasGraph();
return $this->graph
->all($this->uri, $property, 'literal', $lang);
}