question: public static String validateCanal ( final Route route , final Collection < Unit > units , final PlayerID player , final GameData data ) { for ( final Territory routeTerritory : route . getAllTerritories ( ) ) { final Optional < String > result = validateCanal ( routeTerritory , route , units , player , data ) ; if ( result . isPresent ( ) ) { return result . get ( ) ; } } return null ; }
target:  Test a route's canals to see if you can move through it.