Java接口:根据对象类型调用实现类

我有一个接口,其2个实现说:

public interface ObjectProcessor {
  public void process(List objectNames);
}

public CarImpl implements ObjectProcessor {
@override 
public void process(List carNames){
//car logic
} }

public VanImpl implements ObjectProcessor {
@override 
public void process(List vanNames){
//van logic
}
}

现在使用此界面的调用者看起来像:

public void caller(VehicleType vehicleType, List vehicleNames ) {
ObjectProcessor processor = null ;
 if (VehicleType == VehicleType.CAR) {
      processor = new CarImpl();
      processor.process(vehicleNames);
}
}

VehicleType是ENUM这很好用.但无论如何我可以动态调用接口而无需
添加if语句.将来,如果我支持其他车辆,我需要添加一个if语句以及该接口的新实现.我怎么能避免这个？

像这样覆盖枚举中的抽象工厂方法.

public enum VehicleType {
    Car {
        @Override
        public ObjectProcessor createImpl() {
            return new CarImpl();
        }
    },
    Van {
        @Override
        public ObjectProcessor createImpl() {
            return new VanImpl();
        }
    };
    public abstract ObjectProcessor createImpl();
}

public void caller(VehicleType vehicleType, List vehicleNames ) {
    ObjectProcessor processor = vehicleType.createImpl();
    processor.process(vehicleNames);
}

VechicleType将枚举与工厂结合在一起.

或者你可以像这样在枚举中记录所有逻辑.

public enum VehicleType {
    Car {
        @Override
        public ObjectProcessor createImpl() {
            return new ObjectProcessor() {

                @Override
                public void process(List objectNames) {
                    // car logic
                }

            };
        }
    },
    Van {
        @Override
        public ObjectProcessor createImpl() {
            return new ObjectProcessor() {

                @Override
                public void process(List objectNames) {
                    // van logic
                }

            };
        }
    };
    public abstract ObjectProcessor createImpl();
}

在这种情况下,您不再需要实现类(CarImpl,VanImpl,...).