Make ChaosGameDescription fields final and add validation.

src/main/java/edu/ntnu/stud/chaosgame/game/ChaosGameDescription.java

@@ -6,9 +6,9 @@ import edu.ntnu.stud.chaosgame.transformations.Transform2D;
 import java.util.List;
 
 public class ChaosGameDescription {
-    private Vector2D minCoords;
-    private Vector2D maxCoords;
-    private List<Transform2D> transforms;
+    private final Vector2D minCoords;
+    private final Vector2D maxCoords;
+    private final List<Transform2D> transforms;
 
     /**
      * Constructor for ChaosGameDescription
@@ -17,6 +17,9 @@ public class ChaosGameDescription {
      * @param transforms Inputs a list of transformations {@link Transform2D} used in the chaos game.
      */
     public ChaosGameDescription(Vector2D minCoords, Vector2D maxCoords, List<Transform2D> transforms) {
+        if (minCoords == null || maxCoords == null || transforms == null){
+            throw new IllegalArgumentException("Coordinates and transforms must not be null.");
+        }
         this.minCoords = minCoords;
         this.maxCoords = maxCoords;
         this.transforms = transforms;