Restaurant Not Found Exception

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In our restaurant update functionality, we need to handle situations where a user attempts to update a restaurant that doesn't exist.

Let's create a dedicated exception and handler to manage this scenario effectively.

Custom Exception Creation

While we've previously used Optional to handle missing restaurants, now we're retrieving a restaurant as a part of an update, so we'll use a dedicated exception to communicate the specifics of the error.

Here's our custom exception class:

package com.devtiro.restaurant.exceptions;

public class RestaurantNotFoundException extends BaseException {

    public RestaurantNotFoundException() {
    }

    public RestaurantNotFoundException(String message) {
        super(message);
    }

    public RestaurantNotFoundException(String message, Throwable cause) {
        super(message, cause);
    }

    public RestaurantNotFoundException(Throwable cause) {
        super(cause);
    }
}

Exception Handler Implementation

To manage our new exception, we'll add a handler to our existing ErrorController class:

@ControllerAdvice
public class ErrorController {
    // ... existing handlers ...

    @ExceptionHandler(RestaurantNotFoundException.class)
    public ResponseEntity<ErrorDto> handleRestaurantNotFoundException(RestaurantNotFoundException ex) {
        log.error("Caught RestaurantNotFoundException", ex);

        ErrorDto errorDto = ErrorDto.builder()
                .status(HttpStatus.NOT_FOUND.value())
                .message("The specified restaurant wasn't found")
                .build();

        return new ResponseEntity<>(errorDto, HttpStatus.NOT_FOUND);
    }

}

Summary

Created RestaurantNotFoundException for handling non-existent restaurants
Added exception handler to return HTTP 404 responses