feat: implement immutable classes

src/main/java/core/basesyntax/Car.java

@@ -1,25 +1,108 @@
 package core.basesyntax;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
-/**
- * Make this class immutable. See requirements in task description.
- */
-public class Car {
-    private int year;
-    private String color;
-    private List<Wheel> wheels;
-    private Engine engine;
+public final class Car {
+    private final int year;
+    private final String color;
+    private final List<Wheel> wheels;
+    private final Engine engine;
 
-    //implement this class
+    public Car(int year, String color, List<Wheel> wheels, Engine engine) {
+        if (wheels == null) {
+            throw new NullPointerException();
+        }
+
+        this.year = year;
+        this.color = color;
+        this.wheels = cloneWheels(wheels);
+        this.engine = cloneEngine(engine);
+    }
+
+    public int getYear() {
+        return year;
+    }
+
+    public String getColor() {
+        return color;
+    }
+
+    public List<Wheel> getWheels() {
+        return cloneWheels(wheels);
+    }
+
+    public Engine getEngine() {
+        return cloneEngine(engine);
+    }
+
+    public Car changeEngine(Engine engine) {
+        return new Car(year, color, wheels, engine);
+    }
+
+    public Car changeColor(String newColor) {
+        return new Car(year, newColor, wheels, engine);
+    }
+
+    public Car addWheel(Wheel newWheel) {
+        List<Wheel> newWheels = cloneWheels(wheels);
+        newWheels.add(cloneWheel(newWheel));
+        return new Car(year, color, newWheels, engine);
+    }
+
+    private static Engine cloneEngine(Engine engine) {
+        return engine == null ? null : engine.clone();
+    }
+
+    private static Wheel cloneWheel(Wheel wheel) {
+        return wheel == null ? null : wheel.clone();
+    }
+
+    private static List<Wheel> cloneWheels(List<Wheel> wheels) {
+        List<Wheel> clonedWheels = new ArrayList<>();
+
+        if (wheels == null) {
+            return clonedWheels;
+        }
+
+        for (Wheel wheel : wheels) {
+            clonedWheels.add(cloneWheel(wheel));
+        }
+
+        return clonedWheels;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+
+        Car car = (Car) o;
+
+        return year == car.year
+                && Objects.equals(color, car.color)
+                && Objects.equals(wheels, car.wheels)
+                && Objects.equals(engine, car.engine);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(year, color, wheels, engine);
+    }
 
     @Override
     public String toString() {
         return "Car{"
-            + "year=" + year
-            + ", color='" + color + '\''
-            + ", wheels=" + wheels
-            + ", engine=" + engine
-            + '}';
+                + "year=" + year
+                + ", color='" + color + '\''
+                + ", wheels=" + wheels
+                + ", engine=" + engine
+                + '}';
     }
 }

src/main/java/core/basesyntax/Engine.java

@@ -1,16 +1,64 @@
 package core.basesyntax;
 
-public class Engine {
+import java.util.Objects;
+
+public class Engine implements Cloneable {
     private int horsePower;
     private String manufacturer;
 
-    //implement this class
+    public Engine(int horsePower, String manufacturer) {
+        this.horsePower = horsePower;
+        this.manufacturer = manufacturer;
+    }
+
+    public int getHorsePower() {
+        return horsePower;
+    }
+
+    public void setHorsePower(int horsePower) {
+        this.horsePower = horsePower;
+    }
+
+    public String getManufacturer() {
+        return manufacturer;
+    }
+
+    public void setManufacturer(String manufacturer) {
+        this.manufacturer = manufacturer;
+    }
+
+    @Override
+    public Engine clone() {
+        try {
+            return (Engine) super.clone();
+        } catch (CloneNotSupportedException e) {
+            throw new RuntimeException("Can't clone engine", e);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Engine engine = (Engine) o;
+        return horsePower == engine.horsePower
+                && Objects.equals(manufacturer, engine.manufacturer);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(horsePower, manufacturer);
+    }
 
     @Override
     public String toString() {
         return "Engine{"
-            + "horsePower=" + horsePower
-            + ", manufacturer='" + manufacturer + '\''
-            + '}';
+                + "horsePower=" + horsePower
+                + ", manufacturer='" + manufacturer + '\''
+                + '}';
     }
 }

src/main/java/core/basesyntax/Wheel.java

@@ -1,14 +1,52 @@
 package core.basesyntax;
 
-public class Wheel {
+import java.util.Objects;
+
+public class Wheel implements Cloneable {
     private int radius;
 
-    //implement this class
+    public Wheel(int radius) {
+        this.radius = radius;
+    }
+
+    public int getRadius() {
+        return radius;
+    }
+
+    public void setRadius(int radius) {
+        this.radius = radius;
+    }
+
+    @Override
+    public Wheel clone() {
+        try {
+            return (Wheel) super.clone();
+        } catch (CloneNotSupportedException e) {
+            throw new RuntimeException("Can't clone wheel", e);
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        Wheel wheel = (Wheel) o;
+        return radius == wheel.radius;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(radius);
+    }
 
     @Override
     public String toString() {
         return "Wheel{"
-            + "radius=" + radius
-            + '}';
+                + "radius=" + radius
+                + '}';
     }
 }