Concatenate all values for a property into a string.
The default is to join the values together with a space character. This method will return an empty string if the property does not exist.
string $property The name of the property (e.g. foaf:name):
string $glue The string to glue the values together with.:
string $lang The language to filter by (e.g. en):
string Concatenation of all the values.
public function join($property, $glue = ' ', $lang = null) {
$this
->checkHasGraph();
return $this->graph
->join($this->uri, $property, $glue, $lang);
}