Refactor: Added validation

src/main/java/hng_java_boilerplate/product/dto/ProductDTO.java

@@ -1,5 +1,7 @@
 package hng_java_boilerplate.product.dto;
 
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -13,12 +15,28 @@
 @NoArgsConstructor
 @AllArgsConstructor
 public class ProductDTO {
+
     private String id;
+    @NotNull(message = "Name is required")
+    @NotBlank(message = "Name is required")
     private String name;
+
+    @NotNull(message = "Name is required")
+    @NotBlank(message = "Name is required")
     private String description;
+
+    @NotNull(message = "Name is required")
+    @NotBlank(message = "Name is required")
     private String category;
+
+    @NotNull(message = "Name is required")
+    @NotBlank(message = "Name is required")
     private Double price;
+
+    @NotNull(message = "Name is required")
+    @NotBlank(message = "Name is required")
     private String image_url;
+
     private LocalDateTime created_at;
     private LocalDateTime updated_at;
 }