question: public void registerShield ( int worldId , SiegeShield shield ) { List < SiegeShield > mapShields = registeredShields . get ( worldId ) ; if ( mapShields == null ) { mapShields = new ArrayList < SiegeShield > ( ) ; registeredShields . put ( worldId , mapShields ) ; } mapShields . add ( shield ) ; }
target:  Registers geo shield for zone lookup