private function loadStylesheetConstraintFromCache(DataSource $ds)
{
$id = $ds->getId();
if ($this->cache->test($id)) {
$stylesheetConstraint = $this->cache->load($id);
} else {
$csc = new CachingStylesheetConstraint();
$csc->setCacheId($id);
$this->getStylesheetParser()->setRoot($csc);
$stylesheetConstraint = $this->parseStylesheet($ds);
$this->cache->save($stylesheetConstraint, $id);
}
return $stylesheetConstraint;
}
