src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/checks/UserLoggedinCheck.java

@@ -0,0 +1,30 @@
+package ch.unibas.dmi.dbis.cs108.casono.server.app.checks;
+
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.checks.HandlerCheck;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
+import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.Response;
+import java.util.Optional;
+
+public class UserLoggedinCheck implements HandlerCheck {
+    private final UserRegistry userRegistry;
+
+    public UserLoggedinCheck(UserRegistry userRegistry) {
+        this.userRegistry = userRegistry;
+    }
+
+    @Override
+    public Optional<Response> check(Request request) {
+        Optional<User> user = userRegistry.getBySessionId(request.getSessionId());
+        if (user.isPresent()) {
+            return Optional.empty();
+        }
+        return Optional.of(
+                new ErrorResponse(
+                        request.getContext(),
+                        "USER_NOT_LOGGED_IN",
+                        "The execution of this command requires the user to be logged in"));
+    }
+}