public function updateRepr() {
if (null !== $this->sourceId) {
$this->message = sprintf('The service "%s" has a dependency on a non-existent parameter "%s".', $this->sourceId, $this->key);
}
elseif (null !== $this->sourceKey) {
$this->message = sprintf('The parameter "%s" has a dependency on a non-existent parameter "%s".', $this->sourceKey, $this->key);
}
else {
$this->message = sprintf('You have requested a non-existent parameter "%s".', $this->key);
}
}