/**
  * Validates entry param data structure
  *
  * @throws InvalidEntryParamStructure
  */
 public function validate()
 {
     $requiredFields = array_values($this->entryInfo->getSchema());
     foreach ($requiredFields as $required) {
         if (!array_key_exists($required, $this->entryInfo->getData())) {
             $this->errors[] = "{$required} is required.";
         }
     }
     return empty($this->errors);
 }