Made a Duplicate Exception class and made that be called instead for better robustness and consistency

client/src/main/java/client/exception/DuplicateIngredientException.java

@@ -0,0 +1,20 @@
+package client.exception;
+
+public class DuplicateIngredientException extends Exception{
+    private final String ingredientName;
+
+    public DuplicateIngredientException(String ingredientName){
+        super("An ingredient with name " + ingredientName + " already exists, please provide a different name");
+        this.ingredientName = ingredientName;
+    }
+
+    public  DuplicateIngredientException(String ingredientName, String message){
+        super(message);
+        this.ingredientName = ingredientName;
+    }
+
+    public String getIngredientName() {
+        return ingredientName;
+    }
+
+}

client/src/main/java/client/scenes/Ingredient/IngredientListCtrl.java

@@ -1,5 +1,6 @@
 package client.scenes.Ingredient;
 
+import client.exception.DuplicateIngredientException;
 import client.scenes.nutrition.NutritionDetailsCtrl;
 import client.utils.LocaleAware;
 import client.utils.LocaleManager;
@@ -113,6 +114,8 @@ public class IngredientListCtrl implements LocaleAware {
             refresh();                      // reload list from server
         } catch (IOException | InterruptedException e) {
             showError("Failed to create ingredient: " + e.getMessage());
+        } catch (DuplicateIngredientException e) {
+            throw new RuntimeException(e);
         }
     }
 

client/src/main/java/client/scenes/recipe/IngredientsPopupCtrl.java

@@ -1,6 +1,7 @@
 package client.scenes.recipe;
 
 import client.utils.server.ServerUtils;
+import client.exception.DuplicateIngredientException;
 import commons.Ingredient;
 import jakarta.inject.Inject;
 import javafx.fxml.FXML;
@@ -66,17 +67,16 @@ public class IngredientsPopupCtrl {
         try {
             server.createIngredient(name);  // calls POST /api/ingredients
             refresh();                      // reload list from server
-        } catch (IOException e) {
+        } catch (IOException | InterruptedException e) {
-            if (e.getMessage() != null && e.getMessage().startsWith("DUPLICATE:")) {
+
+            showError("Failed to create ingredient: " + e.getMessage());
+        } catch (DuplicateIngredientException e) {
             showError("An ingredient with the name " + name + " already exists." +
                     " Please provide a different name."); //checks if error received has the DUPLICATE string and creates a showError instance with an appropriate error message and description
 
-            } else {
-                showError("Failed to create ingredient: " + e.getMessage());
-            }
-        }  catch (InterruptedException e){
-            showError("Failed to create ingredient: " + e.getMessage());
         }
+
+
     }
 
 

client/src/main/java/client/utils/server/ServerUtils.java

@@ -1,6 +1,7 @@
 package client.utils.server;
 
 import client.utils.ConfigService;
+import client.exception.DuplicateIngredientException;
 import com.fasterxml.jackson.core.type.TypeReference;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.inject.Inject;
@@ -270,7 +271,7 @@ public class ServerUtils {
 
     //creates new ingredients in the ingredient list
 
-    public Ingredient createIngredient(String name) throws IOException, InterruptedException {
+    public Ingredient createIngredient(String name) throws IOException, InterruptedException, DuplicateIngredientException {
         Ingredient ingredient = new Ingredient(name, 0.0, 0.0, 0.0);
         String json = objectMapper.writeValueAsString(ingredient);
 
@@ -280,7 +281,7 @@ public class ServerUtils {
         HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
         final int DUPLICATE_STATUS_CODE = 409;
         if (response.statusCode() == DUPLICATE_STATUS_CODE) {
-            throw new IOException("DUPLICATE: An ingredient with the name '" + name + "' already exists.");
+            throw new DuplicateIngredientException(name);
         }
 
         if (response.statusCode() != statusOK) {