Slighly refactored ControllerAdvices to include handling of Spring's
HTTP Exceptions. This fixes 500 status codes being sent instead of the
correct one.

Fixes GH-67.

Consistently use singular for packages which contain mixed kinds of
classes. Moved a few classes to packages that better fit them.

Error responses now expose exception details.

Exeption handling was broken by
56fe085e (GH-27).

Additionally, removed unused empty constructor

* Remove unused code
* Optimize imports (group 10+ and static imports)
* Remove redundant variable assignments
* Replace explicit type parameters with <>
* Remove redundant catch blocks
* Use varargs instead of explicit array instantiation
* Weaken visibility of methods and fields
* Simplify conditions
* Do not use StringBuilder for simple concatenations
* Fix code style
* Remove invalid Javadoc

The default exception handles all excaptions not handled by the
following handle methods.

It creates a response, containing the HTTP status description
and the exception message.
This response can be serialized into JSON.

remove spingfox for ApiIgnore direction
use swagger-maven-plugin to generate swagger.json before compiling rather than
 dynamically generate it on request

Updated copyright year and adjusted header format to be consistent over
all files and with other ARSnova projects.

Paul-Christian Volkmer authored 10 years ago and Daniel Gerhardt committed 10 years ago

Set default evaluation result to false and throw an AccessDeniedException.
SecurityExceptionControllerAdvice checks if there is an valid login and
decides whether to send HTTP 401 or HTTP 403.

Conflicts:
	src/test/java/de/thm/arsnova/controller/AbstractControllerTest.java

This will send HTTP 501 NOT IMPLEMENTED error in case connector client is
used and not available.

This allows expecting those exceptions in test classes.

The new NoContentException should indicate, that there is no error, but
the server could not provide a response object. This will result in
HTTP Code 204 - NO CONTENT => see RFC2616

Fixed two NullPointerExceptions wich might occure in QuestionService or
by using CouchDBDao from QuestionService.

This checks if there is a user in current security context. If not, an
UnauthorizedException is thrown which will result in HTTP - 401.

This patch uses AbstractController class to add exception handlers
into controllers. These handlers are used to detect some runtime exceptions
which can be thrown in any layer e.g. DAO or service layer.
They recognize NotFoundException and ForbiddenException. Test classes are
able to check if any of these exceptions are thrown during runtime.