Found Needle in Haystack. Fixed? Singelton

ActiveCommand.cpp

@@ -14,15 +14,15 @@ namespace commands
 
     void ActiveCommand::run(stringstream& args)
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         int user_id;
         args >> user_id;
         if (!user_id)
             throw Error(102, "Ein Parameter eines Befehls konnte nicht gelesen werden");
-        const User* u = mgr.get_user(user_id);
+        const User* u = mgr->get_user(user_id);
         if (!u)
             throw Error(401, "Eine solche BenutzerIn existiert nicht.");
-        for (const Assignment* a : mgr.get_assignments_for_user(user_id))
+        for (const Assignment* a : mgr->get_assignments_for_user(user_id))
             cout << a->get_task_id() << "\n";
     }
 } // commands

AddCommand.cpp

@@ -17,21 +17,21 @@ namespace commands
     void AddCommand::run(stringstream& args)
     {
         const string data_type = Util::read_string(args);
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         if (data_type == "user")
         {
             AddUser u;
             args >> u;
-            mgr.add_user(new User(u));
+            mgr->add_user(new User(u));
         }
         else if (data_type == "task")
         {
             AddTask t;
             args >> t;
-            mgr.add_task(new Task(t));
+            mgr->add_task(new Task(t));
         }
         else
             throw Error(102, "Ein Parameter eines Befehls konnte nicht gelesen werden.");
-        mgr.save();
+        mgr->save();
     }
 } // commands

AssignCommand.cpp

@@ -14,21 +14,21 @@ namespace commands
 
     void AssignCommand::run(stringstream& args)
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         int user_id, task_id;
         args >> user_id >> task_id;
         if (!args)
             throw Error(102, "Ein Parameter eines Befehls konnte nicht gelesen werden");
-        const User* u = mgr.get_user(user_id);
+        const User* u = mgr->get_user(user_id);
         if (!u)
             throw Error(401, "Eine solche BenutzerIn existiert nicht.");
-        const Task* t = mgr.get_task(task_id);
+        const Task* t = mgr->get_task(task_id);
         if (!t)
             throw Error(402, "Eine solche Aufgabe existiert nicht.");
-        if (mgr.assignment_exists(user_id, task_id))
+        if (mgr->assignment_exists(user_id, task_id))
             throw Error(302, "Eine solche Zuordnung existiert bereits.");
         Assignment* a = new Assignment(user_id, task_id);
-        mgr.add_assignment(a);
+        mgr->add_assignment(a);
-        mgr.save();
+        mgr->save();
     }
 } // commands

Assignment.cpp

@@ -7,7 +7,14 @@ using util::Manager;
 namespace models {
     Assignment::Assignment(const int& user_id, const int& task_id) : user_id(user_id), task_id(task_id) {
         //validate user exist
-        //Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
+        if (mgr->get_user(user_id) == nullptr) {
+            throw Error(401, "Eine solche BenutzerIn existiert nicht.");
+        }
+        if (mgr->get_task(task_id) == nullptr) {
+            throw Error(402, "Eine solche Aufgabe existiert nicht.");
+        }
+
 
     }
     Assignment::Assignment(): user_id(0), task_id(0) {}

DelCommand.cpp

@@ -14,18 +14,18 @@ namespace commands
 
     void DelCommand::run(stringstream& args)
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         const string data_type = Util::read_string(args);
         int id;
         args >> id;
         if (!args)
             throw Error(102, "Ein Parameter eines Befehls konnte nicht gelesen werden");
         if (data_type == "user")
-            mgr.del_user(id);
+            mgr->del_user(id);
         else if (data_type == "task")
-            mgr.del_task(id);
+            mgr->del_task(id);
         else
             throw Error(102, "Ein Parameter eines Befehls konnte nicht gelesen werden");
-        mgr.save();
+        mgr->save();
     }
 } // commands

ListCommand.cpp

@@ -17,16 +17,16 @@ namespace commands
 
     void ListCommand::run(stringstream& args)
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         const string data_type = Util::read_string(args);
         if (data_type == "users")
-            for (const User* u : mgr.get_users())
+            for (const User* u : mgr->get_users())
                 cout << *u;
         else if (data_type == "tasks")
-            for (const Task* t : mgr.get_tasks())
+            for (const Task* t : mgr->get_tasks())
                 cout << *t;
         else if (data_type == "assignments")
-            for (const Assignment* a : mgr.get_assignments())
+            for (const Assignment* a : mgr->get_assignments())
                 cout << *a;
         else
             throw Error(101, "Befehl ist unbekannt.");

Manager.cpp

@@ -103,7 +103,7 @@ namespace util
     void Manager::update_task_id_index()
     {
         int i = 0;
-        for (const auto& task_pair : this->users)
+        for (const auto& task_pair : this->tasks)
             if (task_pair.second && task_pair.second->get_id() >= i)
                 i = task_pair.second->get_id() + 1;
         this->task_id_index = i;
@@ -129,13 +129,13 @@ namespace util
         return value;
     }
 
-    Manager* Manager::INSTANCE;
+    Manager* Manager::INSTANCE = nullptr;
 
-    Manager& Manager::get_instance()
+    Manager* Manager::get_instance()
     {
-        if (!INSTANCE)
+        if (INSTANCE == nullptr)
             INSTANCE = new Manager();
-        return *INSTANCE;
+        return INSTANCE;
     }
 
     vector<User*> Manager::get_users() const

Manager.h

@@ -30,7 +30,9 @@ namespace util
         void update_task_id_index();
 
     public:
-        static Manager& get_instance();
+        Manager(const Manager&) = delete;
+        Manager& operator=(const Manager&) = delete;
+        static Manager* get_instance();
 
         void save();
         void update_indexes();

ShowCommand.cpp

@@ -18,15 +18,15 @@ namespace commands
 
     void ShowCommand::run(stringstream& args)
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         const string data_type = Util::read_string(args);
         if (data_type == "user")
-            for (User* u : mgr.get_users()) {
+            for (User* u : mgr->get_users()) {
                 AddUser au = {*u};
                 cout << au;
             }
         else if (data_type == "task")
-            for (Task* t : mgr.get_tasks()) {
+            for (Task* t : mgr->get_tasks()) {
                 AddTask at = {*t};
                 cout << at;
             }

Task.cpp

@@ -20,8 +20,8 @@ namespace models
 
     Task::Task(const AddTask& t): id(0), name(t.get_name()), description(t.get_description()), children(t.get_children())
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
-        this->id = mgr.get_task_id();
+        this->id = mgr->get_task_id();
     }
 
 

UnassignCommand.cpp

@@ -13,21 +13,21 @@ namespace commands
 
     void UnassignCommand::run(stringstream& args)
     {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
         int user_id, task_id;
         args >> user_id >> task_id;
         if (!args)
             throw Error(102, "Ein Parameter eines Befehls konnte nicht gelesen werden");
-        const User* u = mgr.get_user(user_id);
+        const User* u = mgr->get_user(user_id);
         if (!u)
             throw Error(401, "Eine solche BenutzerIn existiert nicht.");
-        const Task* t = mgr.get_task(task_id);
+        const Task* t = mgr->get_task(task_id);
         if (!t)
             throw Error(401, "Eine solche Zuordnung existiert nicht.");
-        if (!mgr.assignment_exists(user_id, task_id))
+        if (!mgr->assignment_exists(user_id, task_id))
             throw Error(302, "Eine solche Zuordnung existiert bereits.");
         Assignment as = {user_id, task_id};
-        mgr.del_assignment(as);
+        mgr->del_assignment(as);
-        mgr.save();
+        mgr->save();
     }
 } // commands

User.cpp

@@ -62,8 +62,8 @@ namespace models {
 
 
     istream& operator>>(istream& is, AddUser& u) {
-        Manager& mgr = Manager::get_instance();
+        Manager* mgr = Manager::get_instance();
-        int id = mgr.get_user_id();
+        int id = mgr->get_user_id();
 
         string name, surname;
         is >> name >> surname;

tasks

@@ -1,13 +0,0 @@
-[tasks]
-0 %Eine Aufgabe% %Mit einer längeren Beschreibung%
-1 %Noch eine Aufgabe% %Kurze Beschreibung% 0
-
-[users]
-0 Fleissiger Mitarbeiter
-1 NochEin Mitarbeiter
-
-[assignments]
-0 0
-0 1
-1 1
-