Feat: Implement method to handle validation exception

Author: sreeraj-keyvalue

src/main/java/com/ecommerce/order/exception/CommonException.java

@@ -8,7 +8,7 @@
 @Getter
 @AllArgsConstructor
 public class CommonException extends RuntimeException {
-    private HttpStatusCode statusCode;
-    private String errorCode;
-    private String message;
+    private final HttpStatusCode statusCode;
+    private final String errorCode;
+    private final String message;
 }

src/main/java/com/ecommerce/order/exception/EntityNotFoundException.java

@@ -1,14 +1,13 @@
 package com.ecommerce.order.exception;
 
 import org.springframework.http.HttpStatus;
-import org.springframework.web.bind.annotation.ResponseStatus;
 
-@ResponseStatus(value = HttpStatus.NOT_FOUND)
 public class EntityNotFoundException extends CommonException {
 
     private static final long serialVersionUID = 1L;
 
     public <T> EntityNotFoundException(Class<T> entity) {
         super(HttpStatus.NOT_FOUND, ExceptionCodes.ENTITY_NOT_FOUND, entity.getSimpleName() + " not found");
     }
-}
+
+}

src/main/java/com/ecommerce/order/exception/ExceptionCodes.java

@@ -1,8 +1,9 @@
 package com.ecommerce.order.exception;
 
-import lombok.NoArgsConstructor;
+import lombok.experimental.UtilityClass;
 
-@NoArgsConstructor
+@UtilityClass
 public class ExceptionCodes {
     public static final String ENTITY_NOT_FOUND = "ENTITY_NOT_FOUND";
+    public static final String VALIDATION_ERROR = "VALIDATION_ERROR";
 }

src/main/java/com/ecommerce/order/exception/GlobalExceptionHandler.java

@@ -1,17 +1,54 @@
 package com.ecommerce.order.exception;
 
-import org.springframework.http.ResponseEntity;
-import org.springframework.web.bind.annotation.ControllerAdvice;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.validation.FieldError;
+import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
-import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+import org.springframework.web.context.request.WebRequest;
 
 import com.ecommerce.order.exception.dto.ErrorResponse;
 
-@ControllerAdvice
-public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
     @ExceptionHandler(CommonException.class)
-    public ResponseEntity<ErrorResponse> handleCommonException(CommonException ex) {
-        return ResponseEntity.status(ex.getStatusCode())
-                .body(new ErrorResponse(ex.getStatusCode().value(), ex.getErrorCode(), ex.getMessage()));
+    @ResponseStatus(value = HttpStatus.NOT_FOUND)
+    public ErrorResponse<String> handleCommonException(
+            CommonException ex,
+            WebRequest request) {
+
+        return (new ErrorResponse<String>(
+                ex.getStatusCode().value(),
+                ex.getErrorCode(),
+                ex.getMessage(),
+                request.getDescription(false),
+                new Date()));
     }
-}
+
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    @ResponseStatus(value = HttpStatus.BAD_REQUEST)
+    public ErrorResponse<Map<String, String>> handleValidationException(
+            MethodArgumentNotValidException ex,
+            WebRequest request) {
+        Map<String, String> errorMessages = new HashMap<>();
+        ex.getBindingResult().getAllErrors().forEach(error -> {
+            String fieldName = ((FieldError) error).getField();
+            String errorMessage = error.getDefaultMessage();
+            errorMessages.put(fieldName, errorMessage);
+        });
+
+        return new ErrorResponse<>(
+                HttpStatus.BAD_REQUEST.value(),
+                ExceptionCodes.VALIDATION_ERROR,
+                errorMessages,
+                request.getDescription(false),
+                new Date());
+    }
+
+}

src/main/java/com/ecommerce/order/exception/dto/ErrorResponse.java

@@ -1,10 +1,14 @@
 package com.ecommerce.order.exception.dto;
 
+import java.util.Date;
+
 import lombok.Data;
 
 @Data
-public class ErrorResponse {
+public class ErrorResponse<T> {
     private final int statusCode;
     private final String errorCode;
-    private final String message;
+    private final T message;
+    private final String description;
+    private final Date timestamp;
 }