add validation in request

src/main/java/com/billpaymentservice/bbps/dto/request/ComplaintRequestDTO.java

@@ -1,5 +1,7 @@
 package com.billpaymentservice.bbps.dto.request;
 
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
 import lombok.Getter;
 import lombok.Setter;
 
@@ -7,9 +9,16 @@ import lombok.Setter;
 @Setter
 public class ComplaintRequestDTO extends BaseClass {
 
-	private String ticketDescription; // Complaint description that the user enters
-	private String ticketDisposition; // Complaint disposition
-	private String ticketDispositionCode; // Type of complaint
-	private String txnId; // Transaction ID (optional)
+	@NotBlank(message = "Ticket description cannot be null.")
+	private String ticketDescription;
+
+	@NotBlank(message = "Ticket disposition cannot be null.")
+	private String ticketDisposition;
+
+	@NotBlank(message = "Ticket disposition code cannot be null.")
+	private String ticketDispositionCode;
+
+	@NotBlank(message = "Transaction ID cannot be null.")
+	private String txnId;
 
 }