feat: Implemented the Table Inheritance pattern (#3105)

* sample classes and tests

* sample classes and tests

* read me addition

* fix violations

* fix quality (coverage)

* fix quality (coverage) #2

* resolved comments

table-inheritance/src/test/java/AppTest.java

@@ -0,0 +1,50 @@
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.iluwatar.table.inheritance.App;
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.logging.ConsoleHandler;
+import java.util.logging.Handler;
+import java.util.logging.Logger;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests if the main method runs without throwing exceptions and prints expected output.
+ */
+
+class AppTest {
+
+  @Test
+  void testAppMainMethod() {
+
+    ByteArrayOutputStream outContent = new ByteArrayOutputStream();
+    PrintStream printStream = new PrintStream(outContent);
+
+    System.setOut(printStream);
+
+    Logger logger = Logger.getLogger(App.class.getName());
+
+    Handler handler = new ConsoleHandler() {
+      @Override
+      public void publish(java.util.logging.LogRecord recordObj) {
+        printStream.println(getFormatter().format(recordObj));
+      }
+    };
+    handler.setLevel(java.util.logging.Level.ALL);
+    logger.addHandler(handler);
+
+    App.main(new String[]{});
+
+    String output = outContent.toString();
+
+    assertTrue(output.contains("Retrieved Vehicle:"));
+    assertTrue(output.contains("Toyota"));  // Car make
+    assertTrue(output.contains("Ford"));    // Truck make
+    assertTrue(output.contains("Retrieved Car:"));
+    assertTrue(output.contains("Retrieved Truck:"));
+  }
+}
+
+
+
+

table-inheritance/src/test/java/VehicleDatabaseTest.java

@@ -0,0 +1,169 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import com.iluwatar.table.inheritance.Car;
+import com.iluwatar.table.inheritance.Truck;
+import com.iluwatar.table.inheritance.Vehicle;
+import com.iluwatar.table.inheritance.VehicleDatabase;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit tests for the {@link VehicleDatabase} class.
+ * Tests saving, retrieving, and printing vehicles of different types.
+ */
+class VehicleDatabaseTest {
+
+  private VehicleDatabase vehicleDatabase;
+
+  /**
+   * Sets up a new instance of {@link VehicleDatabase} before each test.
+   */
+  @BeforeEach
+  public void setUp() {
+    vehicleDatabase = new VehicleDatabase();
+  }
+
+  /**
+   * Tests saving a {@link Car} to the database and retrieving it.
+   */
+  @Test
+  void testSaveAndRetrieveCar() {
+    Car car = new Car(2020, "Toyota", "Corolla", 4, 1);
+    vehicleDatabase.saveVehicle(car);
+
+    Vehicle retrievedVehicle = vehicleDatabase.getVehicle(car.getId());
+    assertNotNull(retrievedVehicle);
+    assertEquals(car.getId(), retrievedVehicle.getId());
+    assertEquals(car.getMake(), retrievedVehicle.getMake());
+    assertEquals(car.getModel(), retrievedVehicle.getModel());
+    assertEquals(car.getYear(), retrievedVehicle.getYear());
+
+    Car retrievedCar = vehicleDatabase.getCar(car.getId());
+    assertNotNull(retrievedCar);
+    assertEquals(car.getNumDoors(), retrievedCar.getNumDoors());
+  }
+
+  /**
+   * Tests saving a {@link Truck} to the database and retrieving it.
+   */
+  @Test
+  void testSaveAndRetrieveTruck() {
+    Truck truck = new Truck(2018, "Ford", "F-150", 60, 2);
+    vehicleDatabase.saveVehicle(truck);
+
+    Vehicle retrievedVehicle = vehicleDatabase.getVehicle(truck.getId());
+    assertNotNull(retrievedVehicle);
+    assertEquals(truck.getId(), retrievedVehicle.getId());
+    assertEquals(truck.getMake(), retrievedVehicle.getMake());
+    assertEquals(truck.getModel(), retrievedVehicle.getModel());
+    assertEquals(truck.getYear(), retrievedVehicle.getYear());
+
+    Truck retrievedTruck = vehicleDatabase.getTruck(truck.getId());
+    assertNotNull(retrievedTruck);
+    assertEquals(truck.getLoadCapacity(), retrievedTruck.getLoadCapacity());
+  }
+
+  /**
+   * Tests saving multiple vehicles to the database and printing them.
+   */
+  @Test
+  void testPrintAllVehicles() {
+    Car car = new Car(2020, "Toyota", "Corolla", 4, 1);
+    Truck truck = new Truck(2018, "Ford", "F-150", 60, 2);
+    vehicleDatabase.saveVehicle(car);
+    vehicleDatabase.saveVehicle(truck);
+
+    vehicleDatabase.printAllVehicles();
+
+    Vehicle retrievedCar = vehicleDatabase.getVehicle(car.getId());
+    Vehicle retrievedTruck = vehicleDatabase.getVehicle(truck.getId());
+
+    assertNotNull(retrievedCar);
+    assertNotNull(retrievedTruck);
+  }
+
+  /**
+   * Tests the constructor of {@link Car} with valid values.
+   */
+  @Test
+  void testCarConstructor() {
+    Car car = new Car(2020, "Toyota", "Corolla", 4, 1);
+    assertEquals(2020, car.getYear());
+    assertEquals("Toyota", car.getMake());
+    assertEquals("Corolla", car.getModel());
+    assertEquals(4, car.getNumDoors());
+    assertEquals(1, car.getId()); // Assuming the ID is auto-generated in the constructor
+  }
+
+  /**
+   * Tests the constructor of {@link Car} with invalid number of doors (negative value).
+   */
+  @Test
+  void testCarConstructorWithInvalidNumDoors() {
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      new Car(2020, "Toyota", "Corolla", -4, 1);
+    });
+    assertEquals("Number of doors must be positive.", exception.getMessage());
+  }
+
+  /**
+   * Tests the constructor of {@link Car} with zero doors.
+   */
+  @Test
+  void testCarConstructorWithZeroDoors() {
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      new Car(2020, "Toyota", "Corolla", 0, 1);
+    });
+    assertEquals("Number of doors must be positive.", exception.getMessage());
+  }
+
+  /**
+   * Tests the constructor of {@link Truck} with invalid load capacity (negative value).
+   */
+  @Test
+  void testTruckConstructorWithInvalidLoadCapacity() {
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      new Truck(2018, "Ford", "F-150", -60, 2);
+    });
+    assertEquals("Load capacity must be positive.", exception.getMessage());
+  }
+
+  /**
+   * Tests the constructor of {@link Truck} with zero load capacity.
+   */
+  @Test
+  void testTruckConstructorWithZeroLoadCapacity() {
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      new Truck(2018, "Ford", "F-150", 0, 2);
+    });
+    assertEquals("Load capacity must be positive.", exception.getMessage());
+  }
+
+  /**
+   * Tests setting invalid number of doors in {@link Car} using setter (negative value).
+   */
+  @Test
+  void testSetInvalidNumDoors() {
+    Car car = new Car(2020, "Toyota", "Corolla", 4, 1);
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      car.setNumDoors(-2);
+    });
+    assertEquals("Number of doors must be positive.", exception.getMessage());
+  }
+
+  /**
+   * Tests setting invalid load capacity in {@link Truck} using setter (negative value).
+   */
+  @Test
+  void testSetInvalidLoadCapacity() {
+    Truck truck = new Truck(2018, "Ford", "F-150", 60, 2);
+    IllegalArgumentException exception = assertThrows(IllegalArgumentException.class, () -> {
+      truck.setLoadCapacity(-10);
+    });
+    assertEquals("Load capacity must be positive.", exception.getMessage());
+  }
+}
+
+