code: public function getMapping($className)
      {
          // Try loading mapping from original driver first
          $mapping = null;
          if (null != $this->originalDriver) {
              if ($this->originalDriver instanceof FileDriver) {
                  $mapping = $this->originalDriver->getElement($className);
              }
          }
  
          // If no mapping found try to load mapping file again
          if (null == $mapping) {
              $mappings = $this->loadMappingFile($this->locator->findMappingFile($className));
              $mapping = $mappings[$className];
          }
  
          return $mapping;
      }
docs: Tries to get a mapping for a given class
  
  @param string $className
  
  @return null|array|object