Set up parent category mechanism.

codiki-application/src/main/java/org/codiki/application/category/CategoryUseCases.java

@@ -68,11 +68,14 @@ public class CategoryUseCases {
         }
 
         if (!isNull(subCategoryIds)) {
-            List<Category> subCategories;
-            try {
-                subCategories = categoryPort.findAllByIds(subCategoryIds);
-            } catch (CategoryNotFoundException exception) {
-                throw new CategoryEditionException(exception);
+            List<Category> subCategories = emptyList();
+
+            if (!subCategoryIds.isEmpty()) {
+                try {
+                    subCategories = categoryPort.findAllByIds(subCategoryIds);
+                } catch (CategoryNotFoundException exception) {
+                    throw new CategoryEditionException(exception);
+                }
             }
             categoryBuilder.withSubCategories(subCategories);
         }
@@ -93,4 +96,8 @@ public class CategoryUseCases {
 
         categoryPort.deleteById(categoryId);
     }
+
+    public List<Category> getAll() {
+        return categoryPort.findAll();
+    }
 }