original_string: public function getId()
      {
          $value = $this->getFirstValue(PropertyIds::OBJECT_ID);
          if (is_string($value)) {
              return $value;
          }
          return null;
      }
code: public function getId()
      {
          $value = $this->getFirstValue(PropertyIds::OBJECT_ID);
          if (is_string($value)) {
              return $value;
          }
          return null;
      }
code_tokens: public function getId ( ) { $ value = $ this -> getFirstValue ( PropertyIds :: OBJECT_ID ) ; if ( is_string ( $ value ) ) { return $ value ; } return null ; }
docstring: Returns the object ID.
  
  @return string|null the object ID or <code>null</code> if the object ID is unknown
docstring_tokens: Returns the object ID .