GeneralExceptionHandler.java

package de.rwth.idsg.bikeman.web.rest.exception;

import lombok.extern.slf4j.Slf4j;
import org.hibernate.exception.ConstraintViolationException;
import org.springframework.beans.TypeMismatchException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.MessageSource;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataIntegrityViolationException;
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 org.springframework.web.client.RestClientException;

import javax.servlet.http.HttpServletResponse;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

/**
 * Created by sgokay on 14.07.14.
 */
@ControllerAdvice(basePackages = "de.rwth.idsg.bikeman.web.rest")
@Slf4j
public class GeneralExceptionHandler {

    @Autowired
    private MessageSource messageSource;

    @ExceptionHandler(Exception.class)
    public ResponseEntity<ErrorMessage> processException(Exception e) {
        log.error("Exception happened", e);

        HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
        ErrorMessage msg = new ErrorMessage(
                status.value(),
                status.getReasonPhrase(),
                e.getMessage()
        );
        return new ResponseEntity<>(msg, status);
    }

    @ExceptionHandler(DataAccessException.class)
    public ResponseEntity<ErrorMessage> processDataAccessException(DataAccessException e) {
        log.error("Exception happened", e);

        // Fallback to most general message, when we have no cause
        String errorMsg = e.getMessage();

        // Inception level 1
        if (e.getCause() != null) {
            errorMsg = e.getCause().getMessage();

            // Inception level 2
            if (e.getCause().getCause() != null) {
                errorMsg = e.getCause().getCause().getMessage();
            }
        }

        HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
        ErrorMessage msg = new ErrorMessage(
                status.value(),
                status.getReasonPhrase(),
                errorMsg
        );
        return new ResponseEntity<>(msg, status);
    }

   /**
    * Catches the controller path errors of the Rest API.
    *
    * Example: If a controller declares an integer in the path, but frontend sends anything but an integer.
    */
    @ExceptionHandler(TypeMismatchException.class)
    public ResponseEntity<ErrorMessage> processTypeException(TypeMismatchException e) {
        log.error("Exception happened", e);

        HttpStatus status = HttpStatus.UNPROCESSABLE_ENTITY;
        ErrorMessage msg = new ErrorMessage(
                status.value(),
                status.getReasonPhrase(),
                e.getMessage()
        );
        return new ResponseEntity<>(msg, status);
    }

   /**
    * Catches the Hibernate validation errors and
    * responds with an error message in appropriate language.
    */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<ErrorMessage> processValidationException(MethodArgumentNotValidException e) {
        log.error("Exception happened", e);

        Locale currentLocale =  LocaleContextHolder.getLocale();

        List<FieldError> errors = e.getBindingResult().getFieldErrors();
        List<String> errorMessages = new ArrayList<>();
        for (FieldError fieldError : errors) {
            String localizedError = messageSource.getMessage(fieldError, currentLocale);
            errorMessages.add(localizedError);
        }

        HttpStatus status = HttpStatus.BAD_REQUEST;
        ErrorMessage msg = new ErrorMessage(
                status.value(),
                status.getReasonPhrase(),
                "Validation failed for the submitted form"
        );
        msg.setFieldErrors(errorMessages);
        return new ResponseEntity<>(msg, status);
    }
}