chore: etc

commons/src/main/java/commons/FormalIngredient.java

@@ -76,4 +76,9 @@ public class FormalIngredient extends RecipeIngredient implements Scalable<Forma
     public int hashCode() {
         return Objects.hash(super.hashCode(), amount, unitSuffix);
     }
+
+    @Override
+    public double kcal() {
+        return ingredient.kcalPer100g() * amountInBaseUnit();
+    }
 }

commons/src/main/java/commons/Recipe.java

@@ -37,7 +37,7 @@ import java.util.Objects;
 // TABLE named recipes
 @Entity
 @Table(name = "recipes")
-public class Recipe {
+public class Recipe implements Scalable<Recipe> {
 
     // PRIMARY Key, unique id for recipe, generated automatically.
     @Id
@@ -191,5 +191,16 @@ public class Recipe {
                 ", preparationSteps=" + preparationSteps +
                 '}';
     }
+    public double kcal() {
+        return this.ingredients.stream().mapToDouble(RecipeIngredient::kcal).sum();
+    }
 
+    @Override
+    public Recipe scaleBy(double factor) {
+        return new Recipe(id, name, locale, ingredients.stream().map(ri -> switch (ri) {
+            case FormalIngredient f -> f.scaleBy(factor);
+            case VagueIngredient v -> v;
+            default -> throw new IllegalArgumentException("Unexpected child class of RecipeIngredient!");
+        }).toList(), preparationSteps);
+    }
 }

commons/src/main/java/commons/RecipeIngredient.java

@@ -92,4 +92,5 @@ public abstract class RecipeIngredient {
     public int hashCode() {
         return Objects.hash(id, ingredient);
     }
+    public abstract double kcal();
 }

commons/src/main/java/commons/Scalable.java

@@ -1,8 +1,8 @@
 package commons;
 
-public interface Scalable<IngredientType extends RecipeIngredient> {
-    default IngredientType scaleBy(int numPortions) {
+public interface Scalable<T> {
+    default T scaleBy(int numPortions) {
         return scaleBy((double) numPortions);
     };
-    IngredientType scaleBy(double factor);
+    T scaleBy(double factor);
 }

commons/src/main/java/commons/VagueIngredient.java

@@ -50,4 +50,9 @@ public class VagueIngredient extends RecipeIngredient {
     public int hashCode() {
         return Objects.hashCode(description);
     }
+
+    @Override
+    public double kcal() {
+        return 0;
+    }
 }