Set up 404 status when nonexistent player is requested

gaming-rest/src/main/java/cz/muni/fi/pa165/rest/controllers/PlayerController.java

@@ -4,6 +4,7 @@ import cz.muni.fi.pa165.dto.PlayerDTO;
 import cz.muni.fi.pa165.facade.PlayerFacade;
 import cz.muni.fi.pa165.rest.RootUris;
 import cz.muni.fi.pa165.rest.exception.ResourceAlreadyExistsException;
+import cz.muni.fi.pa165.rest.exception.ResourceNotFoundException;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.MediaType;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -23,7 +24,12 @@ public class PlayerController {
 
     @RequestMapping(value = "/{uuid}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
     public final PlayerDTO findById(@PathVariable("uuid") String uuid) {
-        return playerFacade.getPlayerById(uuid);
+        var playerDTO = playerFacade.getPlayerById(uuid);
+        if (playerDTO != null) {
+            return playerDTO;
+        } else {
+            throw new ResourceNotFoundException();
+        }
     }
 
     @RequestMapping(method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)

gaming-rest/src/main/java/cz/muni/fi/pa165/rest/exception/ResourceNotFoundException.java

+package cz.muni.fi.pa165.rest.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+/**
+ * @author Marek Kadlečík
+ */
+
+@ResponseStatus(value=HttpStatus.NOT_FOUND, reason="The requested player was not found")
+public class ResourceNotFoundException extends RuntimeException {
+    public ResourceNotFoundException() {
+        super(HttpStatus.NOT_FOUND.getReasonPhrase());
+    }
+}
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