Created IngredientService

server/src/main/java/server/database/IngredientRepository.java

@@ -12,5 +12,7 @@ public interface IngredientRepository extends JpaRepository<Ingredient, Long> {
     List<Ingredient> findAllByOrderByNameAsc();
     Page<Ingredient> findAllByOrderByNameAsc(Pageable pageable);
     Optional<Ingredient> findByName(String name);
+
+    boolean existsByName(String name);
 }
 

server/src/main/java/service/IngredientService.java

@@ -0,0 +1,65 @@
+package service;
+
+import commons.Ingredient;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.stereotype.Service;
+import server.database.IngredientRepository;
+
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class IngredientService {
+    IngredientRepository ingredientRepository;
+
+    public IngredientService(IngredientRepository ingredientRepository) {
+        this.ingredientRepository = ingredientRepository;
+    }
+
+    public Optional<Ingredient> findById(Long id) {
+        return ingredientRepository.findById(id);
+    }
+
+    public List<Ingredient> findAll() {
+        return ingredientRepository.findAll();
+    }
+
+    public List<Ingredient> findAll(int limit) {
+        return ingredientRepository.findAll(PageRequest.of(0, limit)).toList();
+    }
+
+    /**
+     * Creates a new ingredient. Returns empty if the recipe with the same name or id already exists.
+     * @param ingredient Ingredient to be saved in the db.
+     * @return The created ingredient (the ingredient arg with a new assigned id) or empty if it already exists in db.
+     */
+    public Optional<Ingredient> create(Ingredient ingredient) {
+        if (ingredientRepository.existsByName(ingredient.getName()) ||
+                ingredientRepository.existsById(ingredient.getId())) {
+            return Optional.empty();
+        }
+
+        return Optional.of(ingredientRepository.save(ingredient));
+    }
+
+    /**
+     * Updates an ingredient. The ingredient with the provided id will be replaced (in db) with the provided ingredient.
+     * @param id id of the ingredient to update.
+     * @param ingredient Ingredient to be saved in the db.
+     * @return The created ingredient (the ingredient arg with a new assigned id.)
+     */
+    public Optional<Ingredient> update(Long id, Ingredient ingredient) {
+        assert id.equals(ingredient.getId()) :
+                "The id of the updated ingredient doesn't match the provided ingredient's id.";
+        if (!ingredientRepository.existsById(id)) {
+            return Optional.empty();
+        }
+
+        return Optional.of(ingredientRepository.save(ingredient));
+    }
+
+    public void delete(Long id) {
+        ingredientRepository.deleteById(id);
+    }
+
+}