/**
* Calls the corresponding function in the block and executes the data retrieval function.
* @return \SimpleXMLElement The XML data tree
*/
public final function callMemcacheBlock()
{
$callback = $this->getCallback();
$db = $this->getDatabase();
$mem = new \System\Cache\Memcache\Memcache();
$xml = null;
if ($mem->keyExists($this->key)) {
$xmlString = $mem->get($this->key);
if ($xmlString) {
//suppress warning here in case of malformed xml
$xml = @simplexml_load_string($xmlString);
if ($xml instanceof \SimpleXMLElement) {
return $xml;
} else {
$errorLogger = \System\Log\ErrorLogger::getInstance();
$errorLogger->out('[MemcacheBlock] Could not read memcache key ' . $this->key . ' as XML. Regenerating.', \System\Log\LoggerLevel::LEVEL_WARNING);
}
}
}
if (is_callable($callback)) {
$xml = call_user_func($callback, $this);
$mem->store($this->key, $xml->asXML(), $this->timeout);
} else {
throw new \System\Error\Exception\InvalidMethodException('The given callback cannot be called. Does it exist and is it public?');
}
return $xml;
}
