feat: fuel-injection을 통한 상속 이해

src/main/java/fuel/Avante.java

@@ -0,0 +1,24 @@
+package fuel;
+
+public class Avante extends Car{
+    private final int DISTANCE_PER_LITER = 15;
+
+    public Avante(int distanceToTravel) {
+        super(distanceToTravel);
+    }
+
+    @Override
+    double getDistancePerLiter() {
+        return DISTANCE_PER_LITER;
+    }
+
+    @Override
+    double getTripDistance() {
+        return super.distanceToTravel;
+    }
+
+    @Override
+    public String getName() {
+        return "Avante";
+    }
+}

src/main/java/fuel/Car.java

@@ -0,0 +1,31 @@
+package fuel;
+
+public abstract class Car {
+    protected final int distanceToTravel;
+
+    protected Car(int distanceToTravel) {
+        this.distanceToTravel = distanceToTravel;
+    }
+
+    /**
+     * 리터당 이동 거리. 즉, 연비
+     */
+    abstract double getDistancePerLiter();
+
+    /**
+     * 여행하려는 거리
+     */
+    abstract double getTripDistance();
+
+    /**
+     * 차종의 이름
+     */
+    public abstract String getName();
+
+    /**
+     * 주입해야할 연료량을 구한다.
+     */
+    public double getChargeQuantity() {
+        return getTripDistance() / getDistancePerLiter();
+    }
+}

src/main/java/fuel/K5.java

@@ -0,0 +1,24 @@
+package fuel;
+
+public class K5 extends Car{
+    private final int DISTANCE_PER_LITER = 13;
+
+    public K5(int distanceToTravel) {
+        super(distanceToTravel);
+    }
+
+    @Override
+    double getDistancePerLiter() {
+        return DISTANCE_PER_LITER;
+    }
+
+    @Override
+    double getTripDistance() {
+        return super.distanceToTravel;
+    }
+
+    @Override
+    public String getName() {
+        return "K5";
+    }
+}

src/main/java/fuel/RentCompany.java

@@ -0,0 +1,28 @@
+package fuel;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class RentCompany {
+    private List<Car> cars = new ArrayList<>();
+
+    public static RentCompany create() {
+        return new RentCompany();
+    }
+
+    public void addCar(Car car) {
+        cars.add(car);
+    }
+
+    public String generateReport() {
+        StringBuilder sb = new StringBuilder();
+        for (Car car : cars) {
+            sb.append(car.getName());
+            sb.append(" : ");
+            sb.append((int) car.getChargeQuantity());
+            sb.append("리터");
+            sb.append("\n");
+        }
+        return sb.toString();
+    }
+}

src/main/java/fuel/Sonata.java

@@ -0,0 +1,24 @@
+package fuel;
+
+public class Sonata extends Car{
+    private final int DISTANCE_PER_LITER = 10;
+
+    public Sonata(int distanceToTravel) {
+        super(distanceToTravel);
+    }
+
+    @Override
+    double getDistancePerLiter() {
+        return DISTANCE_PER_LITER;
+    }
+
+    @Override
+    double getTripDistance() {
+        return super.distanceToTravel;
+    }
+
+    @Override
+    public String getName() {
+        return "Sonata";
+    }
+}

src/test/java/RentCompanyTest.java

@@ -0,0 +1,29 @@
+import fuel.Avante;
+import fuel.K5;
+import fuel.RentCompany;
+import fuel.Sonata;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class RentCompanyTest {
+    private static final String NEWLINE = "\n";
+
+    @Test
+    public void report() throws Exception {
+        RentCompany company = RentCompany.create(); // factory method를 사용해 생성
+        company.addCar(new Sonata(150));
+        company.addCar(new K5(260));
+        company.addCar(new Sonata(120));
+        company.addCar(new Avante(300));
+        company.addCar(new K5(390));
+
+        String report = company.generateReport();
+        assertEquals(report, "Sonata : 15리터" + NEWLINE +
+                                   "K5 : 20리터" + NEWLINE +
+                                   "Sonata : 12리터" + NEWLINE +
+                                   "Avante : 20리터" + NEWLINE +
+                                   "K5 : 30리터" + NEWLINE);
+    }
+
+}