implemented server side exception handler

server/src/main/java/ru/dragonestia/picker/controller/ExceptionHandlerController.java

@@ -1,9 +1,52 @@
 package ru.dragonestia.picker.controller;
 
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
+import ru.dragonestia.picker.exception.*;
 
 @RestControllerAdvice
 public class ExceptionHandlerController {
 
-    // TODO
+    private ResponseEntity<String> error(Exception ex, HttpStatus status) {
+        return ResponseEntity.status(status)
+                .header("X-Server-Exception", ex.getClass().getSimpleName())
+                .body(ex.getMessage());
+    }
+
+    @ExceptionHandler(AdminAccountMutationException.class)
+    ResponseEntity<String> adminAccountMutation(AdminAccountMutationException ex) {
+        return error(ex, HttpStatus.LOCKED);
+    }
+
+    @ExceptionHandler(AlreadyExistsException.class)
+    ResponseEntity<String> alreadyExistsException(AlreadyExistsException ex) {
+        return error(ex, HttpStatus.METHOD_NOT_ALLOWED);
+    }
+
+    @ExceptionHandler(ConflictingPersistParametersException.class)
+    ResponseEntity<String> conflictingPersistParameter(ConflictingPersistParametersException ex) {
+        return error(ex, HttpStatus.NOT_ACCEPTABLE);
+    }
+
+    @ExceptionHandler(DoesNotExistsException.class)
+    ResponseEntity<String> doesNotExists(DoesNotExistsException ex) {
+        return error(ex, HttpStatus.NOT_FOUND);
+    }
+
+    @ExceptionHandler(InvalidIdentifierException.class)
+    ResponseEntity<String> invalidIdentifier(InvalidIdentifierException ex) {
+        return error(ex, HttpStatus.BAD_REQUEST);
+    }
+
+    @ExceptionHandler(NoRoomsAvailableException.class)
+    ResponseEntity<String> noRoomsAvailable(NoRoomsAvailableException ex) {
+        return error(ex, HttpStatus.INSUFFICIENT_STORAGE);
+    }
+
+    @ExceptionHandler(RoomAreFullException.class)
+    ResponseEntity<String> roomAreFull(RoomAreFullException ex) {
+        return error(ex, HttpStatus.INSUFFICIENT_STORAGE);
+    }
 }