to part 6

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

 package io.zipcoder.tc_spring_poll_application;
 
 import io.zipcoder.tc_spring_poll_application.error.ErrorDetail;
+import io.zipcoder.tc_spring_poll_application.error.ValidationError;
 import io.zipcoder.tc_spring_poll_application.exception.ResourceNotFoundException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.MessageSource;
 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.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 
 import javax.servlet.http.HttpServletRequest;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Date;
+import java.util.List;
 
 @ControllerAdvice
 public class RestExceptionHandler {
 
+    @Autowired
+    MessageSource messageSource;
+
     @ExceptionHandler(ResourceNotFoundException.class)
     public ResponseEntity<?> handleResourceNotFoundException(ResourceNotFoundException rnfe, HttpServletRequest request) {
 
         ErrorDetail ed = new ErrorDetail();
 
         ed.setTimeStamp(new Date().getTime());
-        ed.setTitle("Validation Failture");
+        ed.setTitle("Resource Not Found.");
         ed.setStatus(404);
         ed.setDetail("Unable to complete request or entity was not found.");
         ed.setDeveloperMessage(Arrays.toString(rnfe.getStackTrace()));
 
         return new ResponseEntity<>(ed, HttpStatus.NOT_FOUND);
     }
+
+    @ExceptionHandler(MethodArgumentNotValidException.class)
+    public ResponseEntity<?>
+    handleValidationError(MethodArgumentNotValidException manve, HttpServletRequest request){
+        ErrorDetail ed = new ErrorDetail();
+
+        ed.setTimeStamp(new Date().getTime());
+        ed.setTitle("Validation Failure");
+        ed.setStatus(404);
+        ed.setDetail("Unable to complete request.");
+        ed.setDeveloperMessage(Arrays.toString(manve.getStackTrace()));
+
+
+        List<FieldError> fieldErrors =  manve.getBindingResult().getFieldErrors();
+        for(FieldError fe : fieldErrors) {
+
+            List<ValidationError> validationErrorList = ed.getErrors().computeIfAbsent(fe.getField(), k -> new ArrayList<>());
+            ValidationError validationError = new ValidationError();
+            validationError.setCode(fe.getCode());
+            validationError.setMessage(messageSource.getMessage(fe,null));
+            validationErrorList.add(validationError);
+        }
+
+        return new ResponseEntity<>(ed, HttpStatus.BAD_REQUEST);
+    }
 }

src/main/java/io/zipcoder/tc_spring_poll_application/controller/PollController.java

 import org.springframework.web.bind.annotation.*;
 import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 
+import javax.validation.Valid;
 import java.net.URI;
 
 @RestController
         return new ResponseEntity<>(allPolls, HttpStatus.OK);
     }
 
+    @Valid
     @RequestMapping(value="/polls", method = RequestMethod.POST)
     public ResponseEntity<?> createPoll(@RequestBody Poll poll) {
         URI newPollUri = ServletUriComponentsBuilder
         return new ResponseEntity<> (p, HttpStatus.OK);
     }
 
+    @Valid
     @RequestMapping(value="/polls/{pollId}", method=RequestMethod.PUT)
     public ResponseEntity<?> updatePoll(@RequestBody Poll poll, @PathVariable Long pollId) {
         // Save the entity

src/main/java/io/zipcoder/tc_spring_poll_application/domain/Poll.java

 package io.zipcoder.tc_spring_poll_application.domain;
 
+import org.hibernate.validator.constraints.NotEmpty;
+
 import javax.persistence.*;
+import javax.validation.constraints.Size;
 import java.util.Set;
 
 @Entity
     @Column(name = "POLL_ID")
     private Long id;
 
+    @NotEmpty
     @Column(name = "QUESTION")
     private String question;
 
     @OneToMany(cascade = CascadeType.ALL)
     @JoinColumn(name = "POLL_ID")
     @OrderBy
+    @Size(min = 2, max = 6)
     private Set<Option> options;
 
 

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

 package io.zipcoder.tc_spring_poll_application.error;
 
+import java.util.List;
+import java.util.Map;
+
 public class ErrorDetail {
 
     private String title;
     private String detail;
     private long timeStamp;
     private String developerMessage;
+    private Map<String, List<ValidationError>> errors;
 
     public ErrorDetail() {
     }
     public void setDeveloperMessage(String developerMessage) {
         this.developerMessage = developerMessage;
     }
+
+    public Map<String, List<ValidationError>> getErrors() {
+        return errors;
+    }
+
+    public void setErrors(Map<String, List<ValidationError>> errors) {
+        this.errors = errors;
+    }
 }

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

+package io.zipcoder.tc_spring_poll_application.error;
+
+public class ValidationError {
+
+    private String code, 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/message.properties

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