[R1] Validation error handler class

src/main/java/com/mirna/hospitalmanagementapi/infra/handlers/validation/ValidationErrorHandler.java

@@ -0,0 +1,50 @@
+package com.mirna.hospitalmanagementapi.infra.handlers.validation;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.MessageSource;
+import org.springframework.context.i18n.LocaleContextHolder;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.FieldError;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.ResponseStatus;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+/**
+ * This @RestControllerAdvice is used to handle validation errors and return appropriate response messages
+ * 
+ * @author Mirna Gama
+ * @version 1.0
+ */
+@RestControllerAdvice
+public class ValidationErrorHandler {
+
+	@Autowired
+	private MessageSource messageSource;
+	
+	@ResponseStatus(code = HttpStatus.BAD_REQUEST)
+	@ExceptionHandler(MethodArgumentNotValidException.class) 
+	public ResponseEntity<Object> handle(MethodArgumentNotValidException expection) {
+		
+		List<String> validationErrors = new ArrayList<>();
+	
+		List<FieldError> fieldErrors = expection.getBindingResult().getFieldErrors(); 
+		
+		for(FieldError fieldError : fieldErrors) {
+			String validationError = messageSource.getMessage(fieldError, LocaleContextHolder.getLocale());
+			validationErrors.add(validationError);
+		}
+		
+		Map<String, Object> body = new HashMap<>();
+		body.put("errors", validationErrors);
+
+		return new ResponseEntity<>(body, HttpStatus.BAD_REQUEST);
+	}
+	
+}