나는 Java의 초보자이며 추상 클래스를 이해하려고 노력하고 있습니다. 다음은 필자가 작성한 코드입니다. 문제는 그 클래스의 인스턴스를 반환하는 메소드를 작성하는 방법입니다.추상 클래스의 인스턴스를 반환하는 메서드를 작성하는 방법은 무엇입니까?
public abstract class VehicleEngine
{
protected String name;
protected double fabricationCons;
protected double consum;
protected int mileage;
public VehicleEngine(String n, double fC)
{
name = n;
fabricationCons = fC;
mileage = 0;
consum = 0;
}
private void setFabricationCons(double fC)
{
fabricationCons = fC;
}
public abstract double currentConsum();
public String toString()
{
return name + " : " + fabricationCons + " : " + currentConsum();
}
public void addMileage(int km)
{
mileage += km;
}
public double getFabricationConsum()
{
return fabricationCons;
}
public String getName()
{
return name;
}
public int getMileage()
{
return mileage;
}
//public VehicleEngine get(String name){
//if(getName().equals(name)){
//return VehicleEngine;
//}
//return null;
//}
}
public class BenzinVehicle extends VehicleEngine
{
public BenzinVehicle(String n, double fC)
{
super(n, fC);
}
@Override
public double currentConsum()
{
if (getMileage() >= 75000) {
consum = getFabricationConsum() + 0.4;
} else {
consum = getFabricationConsum();
}
return consum;
}
}
public class DieselVehicle extends VehicleEngine
{
public DieselVehicle(String n, double fC)
{
super(n, fC);
}
@Override
public double currentConsum()
{
int cons = 0;
if (getMileage() < 5000) {
consum = getFabricationConsum();
} else {
consum = getFabricationConsum() + (getFabricationConsum() * (0.01 * (getMileage()/5000)));
}
return consum;
}
}
이것은 주입니다.
public class Subject2
{
public static void main(String[] args)
{
VehicleEngine c1 = new BenzinVehicle("Ford Focus 1.9", 5.0);
DieselVehicle c2 = new DieselVehicle("Toyota Yaris 1.4D", 4.0);
BenzinVehicle c3 = new BenzinVehicle("Citroen C3 1.6",5.2);
c1.addMileage(30000);
c1.addMileage(55700);
c2.addMileage(49500);
c3.addMileage(35400);
System.out.println(c1);
System.out.println(c2);
System.out.println(VehicleEngine.get("Citroen C3 1.6")); //this is the line with problems
System.out.println(VehicleEngine.get("Ford Focus "));
}
}
그리고 출력이되어야한다 :
Ford Focus 1.9 : 5.0 : 5.4
Toyota Yaris 1.4D : 4.0 : 4.36
Citroen C3 1.6 : 5.2 : 5.2
null
[공장 패턴] (http://en.wikipedia.org/wiki/Factory_method_pattern)을 확인하십시오. –