finalize error messaging

src/main/java/io/zipcoder/tc_spring_poll_application/exception/ErrorDetail.java

@@ -1,11 +1,23 @@
 package io.zipcoder.tc_spring_poll_application.exception;
 
+import java.util.List;
+import java.util.Map;
+
 public class ErrorDetail {
     private String title;
     private int status;
     private String detail;
     private long timeStamp;
     private String developerMessage;
+    private Map<String, List<ValidationError>> errors;
+
+    public Map<String, List<ValidationError>> getErrors() {
+        return errors;
+    }
+
+    public void setErrors(Map<String, List<ValidationError>> errors) {
+        this.errors = errors;
+    }
 
     public String getTitle() {
         return title;

src/main/java/io/zipcoder/tc_spring_poll_application/exception/RestExceptionHandler.java

@@ -2,14 +2,24 @@ package io.zipcoder.tc_spring_poll_application.exception;
 
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
+import org.springframework.validation.FieldError;
+import org.springframework.context.MessageSource;
+import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
 
+import javax.inject.Inject;
 import javax.servlet.http.HttpServletRequest;
+import java.util.ArrayList;
 import java.util.Date;
+import java.util.List;
 
 @ControllerAdvice
-public class RestExceptionHandler {
+public class RestExceptionHandler extends ResponseEntityExceptionHandler {
+
+    @Inject
+    private MessageSource messageSource;
 
     @ExceptionHandler(ResourceNotFoundException.class)
     public ResponseEntity<?> handleResourceNotFoundException(ResourceNotFoundException rnfe, HttpServletRequest request) {
@@ -21,4 +31,23 @@ public class RestExceptionHandler {
         return new ResponseEntity<>(errorDetail, HttpStatus.NOT_FOUND);
     }
 
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<?> handleValidationError(MethodArgumentNotValidException manve, HttpServletRequest request) {
+        ErrorDetail errorDetail = new ErrorDetail();
+        List<FieldError> fieldErrors = manve.getBindingResult().getFieldErrors();
+        for (FieldError fe : fieldErrors) {
+
+            List<ValidationError> validationErrorList = errorDetail.getErrors().get(fe.getField());
+            if (validationErrorList == null) {
+                validationErrorList = new ArrayList<>();
+                errorDetail.getErrors().put(fe.getField(), validationErrorList);
+            }
+            ValidationError validationError = new ValidationError();
+            validationError.setCode(fe.getCode());
+            validationError.setMessage(messageSource.getMessage(fe, null));
+            validationErrorList.add(validationError);
+        }
+        return new ResponseEntity(errorDetail, HttpStatus.BAD_REQUEST);
+    }
+
 }

src/main/java/io/zipcoder/tc_spring_poll_application/exception/ValidationError.java

@@ -0,0 +1,22 @@
+package io.zipcoder.tc_spring_poll_application.exception;
+
+public class ValidationError {
+    private String code;
+    private String message;
+
+    public String getCode() {
+        return code;
+    }
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}

src/main/resources/messages.properties

@@ -0,0 +1,2 @@
+NotEmpty.poll.question=Question is a required field
+Size.poll.options=Options must be greater than {2} and less than {1}