create ValidationService

Co-Authored-By: xxnitram <xxnitram@users.noreply.github.com>

src/main/java/mops/gruppen2/service/ValidationService.java

@@ -0,0 +1,54 @@
+package mops.gruppen2.service;
+
+import mops.gruppen2.domain.Group;
+import mops.gruppen2.domain.User;
+import mops.gruppen2.domain.Visibility;
+import mops.gruppen2.domain.exception.GroupNotFoundException;
+import mops.gruppen2.domain.exception.NoValueException;
+import mops.gruppen2.domain.exception.UserAlreadyExistsException;
+import java.util.UUID;
+
+public class ValidationService {
+
+    private final ControllerService controllerService;
+    private final UserService userService;
+
+    public ValidationService(ControllerService controllerService, UserService userService) {
+        this.controllerService = controllerService;
+        this.userService = userService;
+    }
+
+    public boolean checkTitleAndDescription(String title, String description) {
+        if(title != null && description != null) return true;
+        throw new NoValueException("Titel und Beschreibung müssen ausgefüllt werden");
+    }
+
+    public boolean checkSearch(String search) {
+        return search != null;
+    }
+
+    public void checkGroup(String title){
+        if(title == null) throw new GroupNotFoundException("@details");
+    }
+
+    public boolean checkIfUserInGroup(Group group, User user) {
+        if (group.getVisibility() == Visibility.PRIVATE) {
+            throw new GroupNotFoundException("Du hast keine Zugriffsberechtigung");
+        }
+        return group.getMembers().contains(user);
+    }
+
+    public Group checkParent(UUID parentId) {
+        Group parent = null;
+        if (!controllerService.idIsEmpty(parentId)) {
+            parent = userService.getGroupById(parentId);
+        }
+        return parent;
+    }
+
+    public void checkIfUserInGroupJoin(Group group, User user) {
+        if(!group.getMembers().contains(user)){
+            throw new UserAlreadyExistsException("@details");
+        }
+    }
+}