Check to see if a property exists for this resource.
This method will return true if the property exists. If the value parameter is given, then it will only return true if the value also exists for that property.
string $property The name of the property (e.g. foaf:name):
mixed $value An optional value of the property:
bool True if value the property exists.
public function hasProperty($property, $value = null) {
$this
->checkHasGraph();
return $this->graph
->hasProperty($this->uri, $property, $value);
}