Re: Visitor pattern vs if-ladder

Philipp wrote :


I set up an enum wich contains an instance of a class which does the
work:

public interface BaseWorker
{
   public void doWork();
}

public class MotorBikeWorker implements BaseWorker
{
   ...

   @Override
   public void doWork()
   {
      .. do something
   }
}

public enum CarWorker
{
  MOTOR_BIKE(new MotorBikeWorker()),
  BIKE(new BikeWorker());

  private BaseWorker worker;

  CarWorker( BaseWorker worker )
  {
      this.worker = worker;
  }

  public BaseWorker getWorker()
  {
     return this.worker;
  }
}

public abstract class Vehicle
{
   private CarWorker workerEnum;

   public Vehicle(CarWorker workerEnum)
   {
      this.workerEnum = workerEnum;
   }

   public final CarWorker getWorkerEnum()
   {
      return this.workerEnum;
   }
}

public class MotorBike extends Vehicle
{
   public MotorBike()
   {
      super(CarWorker.MOTOR_BIKE);
   }
}

You then set up the class with the correct enum. To get work done you
simply call:

vehicleInstance.getWorkerEnum().getWorker().doWork();

// um, this is from memory as my work machine is not connected to
anything

--
Wojtek :-)