Added validations for top level string fields, added error handler to controller

build.gradle

@@ -21,6 +21,7 @@ repositories {
 
 dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-web:2.5.3'
+    implementation 'org.springframework.boot:spring-boot-starter-validation'
     implementation 'com.fasterxml.jackson.core:jackson-databind:2.12.4'
     testImplementation 'org.springframework.boot:spring-boot-starter-test:2.5.3'
     compileOnly 'org.projectlombok:lombok'

src/main/java/com/nisum/paymentvendorsimulator/creditcard/controllers/CreditCardController.java

@@ -3,16 +3,25 @@ package com.nisum.paymentvendorsimulator.creditcard.controllers;
 import com.nisum.paymentvendorsimulator.creditcard.domain.dto.CreditCardRequest;
 import com.nisum.paymentvendorsimulator.creditcard.domain.dto.CreditCardResponse;
 import com.nisum.paymentvendorsimulator.creditcard.services.CreditCardService;
+import com.nisum.paymentvendorsimulator.exceptions.BaseController;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.*;
 
+import javax.validation.ConstraintViolation;
+import javax.validation.ConstraintViolationException;
+import javax.validation.Valid;
+import java.util.Set;
+
 @RestController
 @RequestMapping("/api/cc")
 @CrossOrigin(origins = "*")
-public class CreditCardController {
+public class CreditCardController{
 
   private static final Logger logger = LoggerFactory.getLogger(CreditCardController.class);
 
@@ -20,9 +29,17 @@ public class CreditCardController {
   CreditCardService ccService;
 
   @PostMapping(value = "/authorize", consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
-  public CreditCardResponse authorize(@RequestBody CreditCardRequest ccRequest) {
+  public CreditCardResponse authorize(@Valid @RequestBody CreditCardRequest ccRequest) {
     logger.info("this is CC controller");
+    //validationService.validatePostAuthorization(ccRequest);
     return ccService.authorize(ccRequest);
   }
 
+  @ExceptionHandler(MethodArgumentNotValidException.class)
+  @ResponseStatus(HttpStatus.BAD_REQUEST)
+  public ResponseEntity<String> handleMethodArgumentNotValidException(MethodArgumentNotValidException e) {
+    System.out.println("in exception handler");
+    return new ResponseEntity<>("not valid due to validation error: " + e.getMessage(), HttpStatus.BAD_REQUEST);
+  }
+
 }

src/main/java/com/nisum/paymentvendorsimulator/creditcard/domain/dto/CreditCardRequest.java

@@ -5,14 +5,21 @@ import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
+import javax.validation.constraints.NotBlank;
+
 @Getter
 @Setter
 @AllArgsConstructor
 @NoArgsConstructor
 public class CreditCardRequest {
+
   CreditCardData card;
   CreditCardAmount amount;
+
+  @NotBlank(message="reference can't be blank")
   String reference;
+
+  @NotBlank(message="merchantAccount can't be blank")
   String merchantAccount;
   CreditCardAddress billingAddress;
 //  String returnUrl; // for Adyen payment, not classic integration, do we need?

src/main/java/com/nisum/paymentvendorsimulator/exceptions/BaseControllerAdvice.java

@@ -2,10 +2,13 @@ package com.nisum.paymentvendorsimulator.exceptions;
 
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 
+import javax.validation.ConstraintViolationException;
 import java.time.LocalDateTime;
 
 @ControllerAdvice