protected function mapTypes($array)
  {
    // Hard initialise simple types, lazy load more complex ones.
    foreach ($array as $key => $val) {
      if ($keyType = $this->keyType($key)) {
        $dataType = $this->dataType($key);
        if ($dataType == 'array' || $dataType == 'map') {
          $this->$key = array();
          foreach ($val as $itemKey => $itemVal) {
            if ($itemVal instanceof $keyType) {
              $this->{$key}[$itemKey] = $itemVal;
            } else {
              $this->{$key}[$itemKey] = new $keyType($itemVal);
            }
          }
        } elseif ($val instanceof $keyType) {
          $this->$key = $val;
        } else {
          $this->$key = new $keyType($val);
        }
        unset($array[$key]);
      } elseif (property_exists($this, $key)) {
          $this->$key = $val;
          unset($array[$key]);
      } elseif (property_exists($this, $camelKey = $this->camelCase($key))) {
          // This checks if property exists as camelCase, leaving it in array as snake_case
          // in case of backwards compatibility issues.
          $this->$camelKey = $val;
      }
    }
    $this->modelData = $array;
  }