Merge branch 'code-cleanup' into 'master'

Code cleanup

See merge request !48

pom.xml

@@ -295,6 +295,11 @@
 			<artifactId>metrics-annotation</artifactId>
 			<version>3.0.2</version>
 		</dependency>
+		<dependency>
+			<groupId>org.checkerframework</groupId>
+			<artifactId>checker-qual</artifactId>
+			<version>2.1.9</version>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/de/thm/arsnova/CASLogoutSuccessHandler.java

@@ -34,7 +34,7 @@ import java.io.IOException;
  */
 public class CASLogoutSuccessHandler implements LogoutSuccessHandler {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(CASLogoutSuccessHandler.class);
+	private static final Logger logger = LoggerFactory.getLogger(CASLogoutSuccessHandler.class);
 
 	private String casUrl;
 	private String defaultTarget;
@@ -50,7 +50,7 @@ public class CASLogoutSuccessHandler implements LogoutSuccessHandler {
 		/* Typo in "referer" intended. It is in the spec. */
 		String referrer = request.getHeader("referer");
 		if (response.isCommitted()) {
-			LOGGER.info("Response has already been committed. Unable to redirect to target");
+			logger.info("Response has already been committed. Unable to redirect to target");
 			return;
 		}
 		redirectStrategy.sendRedirect(

src/main/java/de/thm/arsnova/ImageUtils.java

@@ -56,7 +56,7 @@ public class ImageUtils {
 	/* default value is 200 pixel in height, set the value in the configuration file */
 	static final int THUMB_HEIGHT_DEFAULT = 200;
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(ImageUtils.class);
+	private static final Logger logger = LoggerFactory.getLogger(ImageUtils.class);
 
 	@Value("${imageupload.thumbnail.width}")
 	private int thumbWidth = THUMB_WIDTH_DEFAULT;
@@ -200,7 +200,7 @@ public class ImageUtils {
 
 				return result.toString();
 			} catch (IOException e) {
-				LOGGER.error(e.getLocalizedMessage());
+				logger.error(e.getLocalizedMessage());
 				return null;
 			}
 		}
@@ -248,7 +248,7 @@ public class ImageUtils {
 			return baos.toByteArray();
 
 		} catch (IOException e) {
-			LOGGER.error(e.getLocalizedMessage());
+			logger.error(e.getLocalizedMessage());
 		}
 
 		return null;

src/main/java/de/thm/arsnova/LoginAuthenticationFailureHandler.java

@@ -17,8 +17,6 @@
  */
 package de.thm.arsnova;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.security.core.AuthenticationException;
 import org.springframework.security.web.DefaultRedirectStrategy;
 import org.springframework.security.web.RedirectStrategy;
@@ -40,8 +38,6 @@ public class LoginAuthenticationFailureHandler extends
 	private final RedirectStrategy redirectStrategy = new DefaultRedirectStrategy();
 	private String failureUrl;
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(LoginAuthenticationFailureHandler.class);
-
 	@Override
 	public void onAuthenticationFailure(
 			final HttpServletRequest request,

src/main/java/de/thm/arsnova/LoginAuthenticationSucessHandler.java

@@ -17,8 +17,6 @@
  */
 package de.thm.arsnova;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.security.web.authentication.SimpleUrlAuthenticationSuccessHandler;
 
 import javax.servlet.http.HttpServletRequest;
@@ -33,8 +31,6 @@ public class LoginAuthenticationSucessHandler extends
 
 	private String targetUrl;
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(LoginAuthenticationSucessHandler.class);
-
 	@Override
 	protected String determineTargetUrl(
 			final HttpServletRequest request,

src/main/java/de/thm/arsnova/config/SecurityConfig.java

@@ -87,7 +87,7 @@ import java.util.List;
 @EnableWebSecurity
 @Profile("!test")
 public class SecurityConfig extends WebSecurityConfigurerAdapter implements ServletContextAware {
-	private final Logger logger = LoggerFactory.getLogger(SecurityConfig.class);
+	private static final Logger logger = LoggerFactory.getLogger(SecurityConfig.class);
 
 	private ServletContext servletContext;
 

src/main/java/de/thm/arsnova/controller/AudienceQuestionController.java

@@ -28,8 +28,6 @@ import io.swagger.annotations.ApiOperation;
 import io.swagger.annotations.ApiParam;
 import io.swagger.annotations.ApiResponse;
 import io.swagger.annotations.ApiResponses;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -50,8 +48,6 @@ import java.util.List;
 @Api(value = "/audiencequestion", description = "the Audience Question API")
 public class AudienceQuestionController extends PaginationController {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(AudienceQuestionController.class);
-
 	@Autowired
 	private IQuestionService questionService;
 

src/main/java/de/thm/arsnova/controller/ConfigurationController.java

@@ -27,6 +27,7 @@ import org.springframework.web.bind.annotation.ResponseBody;
 
 import javax.servlet.http.HttpServletRequest;
 import java.util.HashMap;
+import java.util.Map;
 
 /**
  * The ConfigurationController provides frontend clients with information necessary to correctly interact with the
@@ -36,7 +37,7 @@ import java.util.HashMap;
 @Controller
 @RequestMapping({"/configuration", "/arsnova-config"})
 public class ConfigurationController extends AbstractController {
-	public static final Logger LOGGER = LoggerFactory
+	private static final Logger logger = LoggerFactory
 			.getLogger(ConfigurationController.class);
 
 	@Value("${api.path:}")
@@ -161,11 +162,11 @@ public class ConfigurationController extends AbstractController {
 
 	@RequestMapping(method = RequestMethod.GET)
 	@ResponseBody
-	public HashMap<String, Object> getConfiguration(HttpServletRequest request) {
-		HashMap<String, Object> config = new HashMap<>();
-		HashMap<String, Boolean> features = new HashMap<>();
-		HashMap<String, String> publicPool = new HashMap<>();
-		HashMap<String, Object> splashscreen = new HashMap<>();
+	public Map<String, Object> getConfiguration(HttpServletRequest request) {
+		Map<String, Object> config = new HashMap<>();
+		Map<String, Boolean> features = new HashMap<>();
+		Map<String, String> publicPool = new HashMap<>();
+		Map<String, Object> splashscreen = new HashMap<>();
 
 		/* The API path could be unknown to the client in case the request was forwarded */
 		if ("".equals(apiPath)) {
@@ -268,7 +269,7 @@ public class ConfigurationController extends AbstractController {
 		}
 
 		if (!"".equals(trackingTrackerUrl)) {
-			HashMap<String, String> tracking = new HashMap<>();
+			Map<String, String> tracking = new HashMap<>();
 			config.put("tracking", tracking);
 
 			tracking.put("provider", trackingProvider);

src/main/java/de/thm/arsnova/controller/CourseController.java

@@ -45,7 +45,7 @@ import java.util.List;
 @RestController
 public class CourseController extends AbstractController {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(CourseController.class);
+	private static final Logger logger = LoggerFactory.getLogger(CourseController.class);
 
 	@Autowired(required = false)
 	private ConnectorClient connectorClient;

src/main/java/de/thm/arsnova/controller/FeedbackController.java

@@ -43,7 +43,7 @@ import org.springframework.web.bind.annotation.RestController;
 @RestController
 public class FeedbackController extends AbstractController {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(FeedbackController.class);
+	private static final Logger logger = LoggerFactory.getLogger(FeedbackController.class);
 
 	@Autowired
 	private IFeedbackService feedbackService;

src/main/java/de/thm/arsnova/controller/LecturerQuestionController.java

@@ -56,7 +56,7 @@ import java.util.List;
 @Api(value = "/lecturerquestion", description = "Operations for Lecture Questions")
 public class LecturerQuestionController extends PaginationController {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(LecturerQuestionController.class);
+	private static final Logger logger = LoggerFactory.getLogger(LecturerQuestionController.class);
 
 	@Autowired
 	private IQuestionService questionService;

src/main/java/de/thm/arsnova/controller/LegacyController.java

@@ -19,8 +19,6 @@ package de.thm.arsnova.controller;
 
 import de.thm.arsnova.services.IQuestionService;
 import de.thm.arsnova.web.DeprecatedApi;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -34,8 +32,6 @@ import org.springframework.web.bind.annotation.ResponseBody;
 @Controller
 public class LegacyController extends AbstractController {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(LegacyController.class);
-
 	@Autowired
 	private IQuestionService questionService;
 

src/main/java/de/thm/arsnova/controller/LoginController.java

@@ -141,7 +141,7 @@ public class LoginController extends AbstractController {
 	@Autowired
 	private UserSessionService userSessionService;
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(LoginController.class);
+	private static final Logger logger = LoggerFactory.getLogger(LoginController.class);
 
 	@RequestMapping(value = { "/auth/login", "/doLogin" }, method = { RequestMethod.POST, RequestMethod.GET })
 	public void doLogin(
@@ -174,7 +174,7 @@ public class LoginController extends AbstractController {
 					return;
 				}
 			} catch (AuthenticationException e) {
-				LOGGER.info("Authentication failed: {}", e.getMessage());
+				logger.info("Authentication failed: {}", e.getMessage());
 			}
 
 			userService.increaseFailedLoginCount(addr);
@@ -197,9 +197,9 @@ public class LoginController extends AbstractController {
 
 						return;
 					}
-					LOGGER.info("LDAPLOGIN: {}", auth.isAuthenticated());
+					logger.info("LDAPLOGIN: {}", auth.isAuthenticated());
 				} catch (AuthenticationException e) {
-					LOGGER.info("No LDAP login: {}", e);
+					logger.info("No LDAP login: {}", e);
 				}
 
 				userService.increaseFailedLoginCount(addr);

src/main/java/de/thm/arsnova/controller/MotdController.java

@@ -25,8 +25,6 @@ import io.swagger.annotations.ApiOperation;
 import io.swagger.annotations.ApiParam;
 import io.swagger.annotations.ApiResponse;
 import io.swagger.annotations.ApiResponses;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -49,8 +47,6 @@ import java.util.List;
 @Api(value = "/motd", description = "the Motd Controller API")
 public class MotdController extends AbstractController {
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(MotdController.class);
-
 	@Autowired
 	private IMotdService motdService;
 
@@ -72,7 +68,7 @@ public class MotdController extends AbstractController {
 			client.setTime(Long.parseLong(clientdate));
 		}
 		if (adminview) {
-			if (sessionkey.equals("null")) {
+			if ("null".equals(sessionkey)) {
 				motds = motdService.getAdminMotds();
 			} else {
 				motds = motdService.getAllSessionMotds(sessionkey);
@@ -96,7 +92,7 @@ public class MotdController extends AbstractController {
 			) {
 		if (motd != null) {
 			Motd newMotd;
-			if (motd.getAudience().equals("session") && motd.getSessionkey() != null) {
+			if ("session".equals(motd.getAudience()) && motd.getSessionkey() != null) {
 				newMotd = motdService.saveSessionMotd(motd.getSessionkey(), motd);
 			} else {
 				newMotd = motdService.saveMotd(motd);
@@ -118,7 +114,7 @@ public class MotdController extends AbstractController {
 			@ApiParam(value = "motdkey from current motd", required = true) @PathVariable final String motdkey,
 			@ApiParam(value = "current motd", required = true) @RequestBody final Motd motd
 			) {
-		if (motd.getAudience().equals("session") && motd.getSessionkey() != null) {
+		if ("session".equals(motd.getAudience()) && motd.getSessionkey() != null) {
 			return motdService.updateSessionMotd(motd.getSessionkey(), motd);
 		} else {
 			return motdService.updateMotd(motd);
@@ -129,7 +125,7 @@ public class MotdController extends AbstractController {
 	@RequestMapping(value = "/{motdkey}", method = RequestMethod.DELETE)
 	public void deleteMotd(@ApiParam(value = "Motd-key from the message that shall be deleted", required = true) @PathVariable final String motdkey) {
 		Motd motd = motdService.getMotd(motdkey);
-		if (motd.getAudience().equals("session")) {
+		if ("session".equals(motd.getAudience())) {
 			motdService.deleteSessionMotd(motd.getSessionkey(), motd);
 		} else {
 			motdService.deleteMotd(motd);

src/main/java/de/thm/arsnova/controller/SecurityExceptionControllerAdvice.java

@@ -62,16 +62,19 @@ public class SecurityExceptionControllerAdvice {
 	@ResponseStatus(HttpStatus.NOT_FOUND)
 	@ExceptionHandler(NotFoundException.class)
 	public void handleNotFoundException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.UNAUTHORIZED)
 	@ExceptionHandler(UnauthorizedException.class)
 	public void handleUnauthorizedException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.UNAUTHORIZED)
 	@ExceptionHandler(AuthenticationCredentialsNotFoundException.class)
 	public void handleAuthenticationCredentialsNotFoundException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ExceptionHandler(AccessDeniedException.class)
@@ -95,30 +98,36 @@ public class SecurityExceptionControllerAdvice {
 	@ResponseStatus(HttpStatus.FORBIDDEN)
 	@ExceptionHandler(ForbiddenException.class)
 	public void handleForbiddenException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.NO_CONTENT)
 	@ExceptionHandler(NoContentException.class)
 	public void handleNoContentException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.BAD_REQUEST)
 	@ExceptionHandler(BadRequestException.class)
 	public void handleBadRequestException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.PRECONDITION_FAILED)
 	@ExceptionHandler(PreconditionFailedException.class)
 	public void handlePreconditionFailedException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
 	@ExceptionHandler(NotImplementedException.class)
 	public void handleNotImplementedException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 
 	@ResponseStatus(HttpStatus.PAYLOAD_TOO_LARGE)
 	@ExceptionHandler(PayloadTooLargeException.class)
 	public void handlePayloadTooLargeException(final Exception e, final HttpServletRequest request) {
+		/* No implementation - handled solely by annotations */
 	}
 }

src/main/java/de/thm/arsnova/controller/SessionController.java

@@ -63,7 +63,7 @@ import java.util.List;
 @Api(value = "/session", description = "the Session Controller API")
 public class SessionController extends PaginationController {
 
-	public static final Logger LOGGER = LoggerFactory.getLogger(SessionController.class);
+	private static final Logger logger = LoggerFactory.getLogger(SessionController.class);
 
 	@Autowired
 	private ISessionService sessionService;
@@ -172,7 +172,7 @@ public class SessionController extends PaginationController {
 			) {
 		List<Session> sessions;
 
-		if (!username.equals("")) {
+		if (!"".equals(username)) {
 			try {
 				if (ownedOnly && !visitedOnly) {
 					sessions = sessionService.getUserSessions(username);
@@ -206,7 +206,7 @@ public class SessionController extends PaginationController {
 			return null;
 		}
 
-		if (sortby != null && sortby.equals("shortname")) {
+		if ("shortname".equals(sortby)) {
 			Collections.sort(sessions, new SessionShortNameComparator());
 		} else {
 			Collections.sort(sessions, new SessionNameComparator());
@@ -242,7 +242,7 @@ public class SessionController extends PaginationController {
 			return null;
 		}
 
-		if (sortby != null && sortby.equals("shortname")) {
+		if ("shortname".equals(sortby)) {
 			Collections.sort(sessions, new SessionInfoShortNameComparator());
 		} else {
 			Collections.sort(sessions, new SessionInfoNameComparator());

src/main/java/de/thm/arsnova/controller/SocketController.java

@@ -57,7 +57,7 @@ public class SocketController extends AbstractController {
 	@Autowired
 	private ARSnovaSocket server;
 
-	private static final Logger LOGGER = LoggerFactory.getLogger(SocketController.class);
+	private static final Logger logger = LoggerFactory.getLogger(SocketController.class);
 
 	@ApiOperation(value = "requested to assign Websocket session",
 			nickname = "authorize")
@@ -70,13 +70,13 @@ public class SocketController extends AbstractController {
 	public void authorize(@ApiParam(value = "sessionMap", required = true) @RequestBody final Map <String, String> sessionMap, @ApiParam(value = "response", required = true) final HttpServletResponse response) {
 		String socketid = sessionMap.get("session");
 		if (null == socketid) {
-			LOGGER.debug("Expected property 'session' missing");
+			logger.debug("Expected property 'session' missing");
 			response.setStatus(HttpStatus.BAD_REQUEST.value());
 			return;
 		}
 		User u = userService.getCurrentUser();
 		if (null == u) {
-			LOGGER.debug("Client {} requested to assign Websocket session but has not authenticated", socketid);
+			logger.debug("Client {} requested to assign Websocket session but has not authenticated", socketid);
 			response.setStatus(HttpStatus.FORBIDDEN.value());
 			return;
 		}

src/main/java/de/thm/arsnova/controller/UserController.java

@@ -48,7 +48,7 @@ public class UserController extends AbstractController {
 	@Autowired
 	private UserSessionService userSessionService;
 
-	public static final Logger LOGGER = LoggerFactory
+	private static final Logger logger = LoggerFactory
 			.getLogger(UserController.class);
 
 	@RequestMapping(value = "/register", method = RequestMethod.POST)

src/main/java/de/thm/arsnova/domain/LearningProgressFactory.java

@@ -41,7 +41,7 @@ public class LearningProgressFactory implements NovaEventVisitor, ILearningProgr
 	@Override
 	public LearningProgress create(String progressType, String questionVariant) {
 		VariantLearningProgress learningProgress;
-		if (progressType.equals("questions")) {
+		if ("questions".equals(progressType)) {
 			learningProgress = new QuestionBasedLearningProgress(databaseDao);
 		} else {
 			learningProgress = new PointBasedLearningProgress(databaseDao);