Implement review fixes

<UserStory> 1960: Service Refactoring </UserStory>

UserStory #1960

<Changes>
1. Replaced the Controller load/save workflow with initialize() and shutdown() methods.
2. Moved startup checks such as admin verification, low stock alerts, and payment reminders into Controller::initialize().
3. Updated UserInterface to use the new Controller initialization and shutdown flow.
4. Updated DataStore::getUsers() and DataStore::getNotifications() to load data directly from shared memory.
5. Added logic to rebuild user notification mappings when user data is loaded from shared memory.
6. Implemented user and notification persistence through DataStore::saveUsers() and DataStore::saveNotifications().
7. Updated UserManagementService to use TrackedRecord-based shared memory records.
8. Added DataStore locking and unlocking to user management operations for synchronization.
9. Updated createUser(), updateUserDetails(), removeUser(), and deleteNotification() to persist changes through shared memory.
10. Removed legacy loadUsers() and saveUsers() implementations from UserManagementService.
11. Added required header dependencies for shared memory support.
</Changes>

<Test>
N/A
</Test>

<Review>
Sreeja Reghukumar, please review
</Review>

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem.vcxproj

@@ -157,6 +157,7 @@
     <ClInclude Include="core\patterns\Observer.h" />
     <ClInclude Include="core\patterns\Subject.h" />
     <ClInclude Include="datastores\DataStore.h" />
+    <ClInclude Include="datastores\DataStoreLockGuard.h" />
     <ClInclude Include="datastores\sharedmemory\FileHeader.h" />
     <ClInclude Include="datastores\sharedmemory\MappingInfo.h" />
     <ClInclude Include="datastores\sharedmemory\RecordState.h" />

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.cpp

@@ -588,63 +588,37 @@ void Controller::configureNotifications(bool paymentNotifications, bool serviceN
 }
 
 /*
-Function: loadSystemData
+Function: initialize
-Description: Loads all system data from persistent storage into memory.
+Description: Initializes the system and run system checks to ensure critical configurations, such as verifying admin existence.
-             Invokes the respective management services to load users, inventory items, services,
-             combo packages, service bookings, job cards, invoices, and observers.
 Parameters:
     - None
 Returns:
-    - void
+    - bool
 */
-void Controller::loadSystemData()
+bool Controller::initialize()
 {
-    m_userManagementService.loadUsers();
+    auto& dataStore = DataStore::getInstance();
-    m_inventoryManagementService.loadInventoryItems();
-    m_serviceManagementService.loadServices();
-    m_serviceManagementService.loadComboPackages();
-    m_serviceManagementService.loadServiceBookings();
-    m_serviceManagementService.loadJobCards();
-    m_paymentManagementService.loadInvoices();
-    m_serviceManagementService.loadObservers();
-    m_paymentManagementService.loadObservers();
-    m_inventoryManagementService.loadObservers();
-}
 
-/*
+    if (!dataStore.initialize())
-Function: saveSystemData
+    {
-Description: Saves all system data from memory back to persistent storage.
+        return false;
-             Invokes the respective management services to save users, inventory items, services,
+    }
-             combo packages, service bookings, job cards, invoices, and observers.
-Parameters:
-    - None
-Returns:
-    - void
-*/
-void Controller::saveSystemData()
-{
-    m_userManagementService.saveUsers();
-    m_inventoryManagementService.saveInventoryItems();
-    m_serviceManagementService.saveServices();
-    m_serviceManagementService.saveComboPackages();
-    m_serviceManagementService.saveServiceBookings();
-    m_serviceManagementService.saveJobCards();
-    m_paymentManagementService.saveInvoices();
-    m_serviceManagementService.saveObservers();
-    m_paymentManagementService.saveObservers();
-    m_inventoryManagementService.saveObservers();
-}
-
-/*
-Function: runSystemChecks
-Description: Runs system checks to ensure critical configurations, such as verifying admin existence.
-Parameter: None
-Return type: void
-*/
-void Controller::runSystemChecks()
-{
     m_userManagementService.ensureAdminExists();
     m_inventoryManagementService.sendLowStockAlerts();
     m_paymentManagementService.sendPaymentReminders();
+    return true;
 }
 
+/*
+Function: shutdown
+Description: Shutdown the system, and do necessary cleanups
+Parameters:
+    - None
+Returns:
+    - void
+*/
+void Controller::shutdown()
+{
+    auto& dataStore = DataStore::getInstance();
+    dataStore.shutdown();
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/controllers/Controller.h

@@ -70,7 +70,6 @@ public:
     util::Vector<const Notification*> getNotifications();
     void deleteNotification(const std::string& notificationID);
     void configureNotifications(bool paymentNotifications, bool serviceNotifications);
-    void loadSystemData();
+    bool initialize();
-    void saveSystemData();
+    void shutdown();
-    void runSystemChecks();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStore.cpp

@@ -228,6 +228,22 @@ Returns:
 */
 util::Map<std::string, TrackedRecord<User>>& DataStore::getUsers()
 {
+    auto users = loadRecords<User, SerializedUser>(m_users);
+    refreshCache(m_userCache, users);
+    auto& notifications = getNotifications();
+    int numberOfNotifications = m_notificationCache.getSize();
+    for (int index = 0; index < numberOfNotifications; index++)
+    {
+        Notification* notification = notifications.getValueAt(index).data;
+        const std::string& recipientUserId = notification->getRecipientUserId();
+        int userIndex = m_userCache.find(recipientUserId);
+        if (userIndex == -1)
+        {
+            throw std::runtime_error("Invalid recipient user ID");
+        }
+        User* user = m_userCache.getValueAt(userIndex).data;
+        user->addNotification(notification);
+    }
     return m_userCache;
 }
 
@@ -241,6 +257,8 @@ Returns:
 */
 util::Map<std::string, TrackedRecord<Notification>>& DataStore::getNotifications()
 {
+    auto notifications = loadRecords<Notification, SerializedNotification>(m_notifications);
+    refreshCache(m_notificationCache, notifications);
     return m_notificationCache;
 }
 
@@ -371,6 +389,8 @@ Returns:
 */
 void DataStore::saveUsers()
 {
+    saveRecords<User, SerializedUser>(m_users, m_userCache);
+    saveNotifications();
 }
 
 /*
@@ -383,6 +403,7 @@ Returns:
 */
 void DataStore::saveNotifications()
 {
+    saveRecords<Notification, SerializedNotification>(m_notifications, m_notificationCache);
 }
 
 /*

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/DataStoreLockGuard.h

@@ -0,0 +1,28 @@
+/*
+File: DataStoreLockGuard.h
+Description: Defines the DataStoreLockGuard class used to manage DataStore
+             locking and unlocking automatically within a scope.
+Author: Trenser
+Date: 12-June-2026
+*/
+
+#pragma once
+#include "DataStore.h"
+
+class DataStoreLockGuard
+{
+public:
+    explicit DataStoreLockGuard(DataStore& dataStore)
+        : m_dataStore(dataStore)
+    {
+        m_dataStore.lockDataStore();
+    }
+    ~DataStoreLockGuard()
+    {
+        m_dataStore.unlockDataStore();
+    }
+    DataStoreLockGuard(const DataStoreLockGuard&) = delete;
+    DataStoreLockGuard& operator=(const DataStoreLockGuard&) = delete;
+private:
+    DataStore& m_dataStore;
+};

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/datastores/sharedmemory/SharedMemory.cpp

@@ -10,6 +10,7 @@ Created: 11-June-2026
 */
 
 #include "SharedMemory.h"
+#include "Windows.h"
 #include "Config.h"
 
 /*

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.cpp

@@ -9,7 +9,6 @@ Date: 19-May-2026
 
 #include <sstream>
 #include <stdexcept>
-#include "SerializedRecords.h"
 #include "ComboPackage.h"
 #include "Service.h"
 #include "Factory.h"
@@ -29,8 +28,7 @@ Returns:
 ComboPackage::ComboPackage()
     : m_id("CMP" + std::to_string(++m_uid)),
     m_status(util::State::ACTIVE),
-    m_discountPercentage(0.0) {
+    m_discountPercentage(0.0) {}
-}
 
 /*
 Function: ComboPackage
@@ -272,38 +270,72 @@ static util::Vector<std::string> getServiceIDsAsVector(const std::string& servic
 
 /*
 Function: serialize
-Description: Serializes the ComboPackage object into a SerializedComboPackage record.
+Description: Serializes the combo package into a CSV-formatted string.
 Parameters:
     - None
 Returns:
-    - SerializedComboPackage: Serialized representation of the combo package
+    - std::string: Serialized combo package record
 */
-SerializedComboPackage ComboPackage::serialize() const
+std::string ComboPackage::serialize() const
 {
-    SerializedComboPackage serialized = {};
+    std::ostringstream serializedComboPackage;
-    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    serializedComboPackage << m_id << ','
-    strcpy_s(serialized.packageName, sizeof(serialized.packageName), m_packageName.c_str());
+        << m_packageName << ','
-    strcpy_s(serialized.serviceIDs, sizeof(serialized.serviceIDs), getServiceIDsAsString(m_serviceIDs).c_str());
+        << m_discountPercentage << ','
-    serialized.discountPercentage = m_discountPercentage;
+        << getServiceIDsAsString(m_serviceIDs) << ','
-    serialized.status = m_status;
+        << util::getStateString(m_status);
-    return serialized;
+    return serializedComboPackage.str();
 }
 
 /*
 Function: deserialize
-Description: Deserializes a SerializedComboPackage record into a ComboPackage object.
+Description: Deserializes a CSV-formatted string into a ComboPackage object.
 Parameters:
-    - serializedComboPackage: const SerializedComboPackage&, serialized combo package record
+    - record: const std::string&, serialized combo package record
 Returns:
     - ComboPackage*: Pointer to the deserialized ComboPackage object
+Throws:
+    - std::runtime_error if data is invalid
 */
-ComboPackage* ComboPackage::deserialize(const SerializedComboPackage& serializedComboPackage)
+ComboPackage* ComboPackage::deserialize(const std::string& record)
 {
-    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serializedComboPackage.serviceIDs);
+    std::string id, packageName;
+    std::string discountPercentageString, serviceIDsString, statusString;
+    double discountPercentage;
+    std::istringstream serializedComboPackage(record);
+    getline(serializedComboPackage, id, ',');
+    getline(serializedComboPackage, packageName, ',');
+    getline(serializedComboPackage, discountPercentageString, ',');
+    getline(serializedComboPackage, serviceIDsString, ',');
+    getline(serializedComboPackage, statusString, ',');
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid combo package data");
+    }
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    util::State status = util::getState(statusString);
     return Factory::getObject<ComboPackage>(
-        serializedComboPackage.id,
+        id,
-        serializedComboPackage.packageName,
+        packageName,
-        serializedComboPackage.discountPercentage,
+        discountPercentage,
         serviceIDs,
-        serializedComboPackage.status);
+        status
-}
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for combo package serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,PackageName,DiscountPercentage,ServiceIDs,Status")
+*/
+std::string ComboPackage::getHeaders()
+{
+    return "ID,PackageName,DiscountPercentage,ServiceIDs,Status";
+}

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ComboPackage.h

@@ -12,7 +12,6 @@ Date: 19-May-2026
 #include "Enums.h"
 
 class Service;
-class SerializedComboPackage;
 
 class ComboPackage
 {
@@ -39,6 +38,7 @@ public:
     void setDiscountPercentage(double discountPercentage);
     void setServices(const util::Map<std::string, Service*>& services);
     void setState(util::State status);
-    SerializedComboPackage serialize() const;
+    std::string serialize() const;
-    static ComboPackage* deserialize(const SerializedComboPackage&);
+    static ComboPackage* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.cpp

@@ -9,7 +9,6 @@ Date:19-May-2026
 
 #include <sstream>
 #include <stdexcept>
-#include "SerializedRecords.h"
 #include "JobCard.h"
 #include "Factory.h"
 #include "StringHelper.h"
@@ -29,8 +28,7 @@ JobCard::JobCard()
     m_booking(nullptr),
     m_service(nullptr),
     m_technician(nullptr),
-    m_status(util::ServiceJobStatus()) {
+    m_status(util::ServiceJobStatus()) {}
-}
 
 /*
 Function: JobCard
@@ -67,8 +65,7 @@ JobCard::JobCard(const std::string& bookingId,
     m_technician(technician),
     m_assignedDate(assignedDate),
     m_status(status),
-    m_completionDate(completionDate) {
+    m_completionDate(completionDate) {}
-}
 
 /*
 Function: JobCard (parameterized constructor with ID)
@@ -354,41 +351,79 @@ void JobCard::setCompletionDate(const util::Timestamp& completionDate)
 
 /*
 Function: serialize
-Description: Serializes the JobCard object into a SerializedJobCard record.
+Description: Serializes the job card into a CSV-formatted string.
 Parameters:
     - None
 Returns:
-    - SerializedJobCard: Serialized representation of the job card
+    - std::string: Serialized job card record
 */
-SerializedJobCard JobCard::serialize() const
+std::string JobCard::serialize() const
 {
-    SerializedJobCard serialized = {};
+    std::ostringstream serializedJobCard;
-    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    serializedJobCard << m_id << ','
-    strcpy_s(serialized.bookingId, sizeof(serialized.bookingId), m_bookingId.c_str());
+        << m_bookingId << ','
-    strcpy_s(serialized.serviceId, sizeof(serialized.serviceId), m_serviceId.c_str());
+        << m_serviceId << ','
-    strcpy_s(serialized.technicianId, sizeof(serialized.technicianId), m_technicianId.c_str());
+        << m_technicianId << ','
-    serialized.assignedDate = m_assignedDate;
+        << m_assignedDate.toString() << ','
-    serialized.status = m_status;
+        << util::getServiceJobStatusString(m_status) << ','
-    serialized.completionDate = m_completionDate;
+        << m_completionDate.toString();
-    return serialized;
+    return serializedJobCard.str();
 }
 
 /*
 Function: deserialize
-Description: Deserializes a SerializedJobCard record into a JobCard object.
+Description: Deserializes a CSV-formatted string into a JobCard object.
 Parameters:
-    - serializedJobCard: const SerializedJobCard&, serialized job card record
+    - record: const std::string&, serialized job card record
 Returns:
     - JobCard*: Pointer to the deserialized JobCard object
+Throws:
+    - std::runtime_error if timestamp parsing fails
 */
-JobCard* JobCard::deserialize(const SerializedJobCard& serializedJobCard)
+JobCard* JobCard::deserialize(const std::string& record)
 {
+    std::string id, bookingId, serviceId, technicianId;
+    std::string assignedDateString, statusString, completionDateString;
+    std::istringstream serializedJobCard(record);
+    getline(serializedJobCard, id, ',');
+    getline(serializedJobCard, bookingId, ',');
+    getline(serializedJobCard, serviceId, ',');
+    getline(serializedJobCard, technicianId, ',');
+    getline(serializedJobCard, assignedDateString, ',');
+    getline(serializedJobCard, statusString, ',');
+    getline(serializedJobCard, completionDateString, ',');
+    util::Timestamp assignedDate;
+    util::Timestamp completionDate;
+    try
+    {
+        assignedDate = util::Timestamp::fromString(assignedDateString);
+        completionDate = util::Timestamp::fromString(completionDateString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid timestamp");
+    }
+    util::ServiceJobStatus status = util::getServiceJobStatus(statusString);
     return Factory::getObject<JobCard>(
-        serializedJobCard.id,
+        id,
-        serializedJobCard.bookingId,
+        bookingId,
-        serializedJobCard.serviceId,
+        serviceId,
-        serializedJobCard.technicianId,
+        technicianId,
-        serializedJobCard.assignedDate,
+        assignedDate,
-        serializedJobCard.status,
+        status,
-        serializedJobCard.completionDate);
+        completionDate
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for job card serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,BookingID,ServiceID,TechnicianID,AssignedDate,Status,CompletionDate")
+*/
+std::string JobCard::getHeaders()
+{
+    return "ID,BookingID,ServiceID,TechnicianID,AssignedDate,Status,CompletionDate";
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/JobCard.h

@@ -15,7 +15,6 @@ Date:19-May-2026
 class ServiceBooking;
 class Service;
 class User;
-struct SerializedJobCard;
 
 class JobCard
 {
@@ -35,11 +34,11 @@ public:
     JobCard();
     JobCard(const std::string& bookingId,
         ServiceBooking* booking,
-        Service* service,
+        Service* service, 
-        const std::string& serviceId,
+        const std::string& serviceId, 
-        const std::string& technicianId,
+        const std::string& technicianId, 
-        User* technician,
+        User* technician, 
-        const util::Timestamp& assignedDate,
+        const util::Timestamp& assignedDate, 
         util::ServiceJobStatus status,
         const util::Timestamp& completionDate
     );
@@ -71,6 +70,7 @@ public:
     void setAssignedDate(const util::Timestamp& assignedDate);
     void setStatus(util::ServiceJobStatus status);
     void setCompletionDate(const util::Timestamp& completionDate);
-    SerializedJobCard serialize() const;
+    std::string serialize() const;
-    static JobCard* deserialize(const SerializedJobCard&);
+    static JobCard* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Service.cpp

@@ -8,7 +8,6 @@ Date: 19-May-2026
 */
 
 #include <sstream>
-#include "SerializedRecords.h"
 #include "Service.h"
 #include "InventoryItem.h"
 #include "StringHelper.h"
@@ -28,8 +27,7 @@ Returns:
 Service::Service()
     : m_id("SRV" + std::to_string(++m_uid)),
     m_status(util::State::ACTIVE),
-    m_laborCost(0.0) {
+    m_laborCost(0.0) {}
-}
 
 /*
 Function: Service
@@ -46,7 +44,7 @@ Service::Service(const std::string& name, const util::Map<std::string, Inventory
     m_name(name),
     m_requiredInventoryItems(requiredInventoryItems),
     m_status(util::State::ACTIVE),
-    m_laborCost(laborCost)
+    m_laborCost(laborCost) 
 {
     int numberOfInventoryItems = m_requiredInventoryItems.getSize();
     auto inventoryItemPointers = m_requiredInventoryItems.getValues();
@@ -268,38 +266,72 @@ static util::Vector<std::string> getInventoryItemIDsAsVector(const std::string&
 
 /*
 Function: serialize
-Description: Serializes the Service object into a SerializedService record.
+Description: Serializes the service into a CSV-formatted string.
 Parameters:
     - None
 Returns:
-    - SerializedService: Serialized representation of the service
+    - std::string: Serialized service record
 */
-SerializedService Service::serialize() const
+std::string Service::serialize() const
 {
-    SerializedService serialized = {};
+    std::ostringstream serializedService;
-    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    serializedService << m_id << ','
-    strcpy_s(serialized.name, sizeof(serialized.name), m_name.c_str());
+        << m_name << ','
-    strcpy_s(serialized.inventoryItemIDs, sizeof(serialized.inventoryItemIDs), getInventoryItemIDsAsString(m_requiredInventoryItemIDs).c_str());
+        << getInventoryItemIDsAsString(m_requiredInventoryItemIDs) << ','
-    serialized.laborCost = m_laborCost;
+        << m_laborCost << ','
-    serialized.status = m_status;
+        << util::getStateString(m_status);
-    return serialized;
+    return serializedService.str();
 }
 
 /*
 Function: deserialize
-Description: Deserializes a SerializedService record into a Service object.
+Description: Deserializes a CSV-formatted string into a Service object.
 Parameters:
-    - serializedService: const SerializedService&, serialized service record
+    - record: const std::string&, serialized service record
 Returns:
     - Service*: Pointer to the deserialized Service object
+Throws:
+    - std::runtime_error if labor cost parsing fails
 */
-Service* Service::deserialize(const SerializedService& serializedService)
+Service* Service::deserialize(const std::string& record)
 {
-    util::Vector<std::string> inventoryItemIDs = getInventoryItemIDsAsVector(serializedService.inventoryItemIDs);
+    std::string id, name;
+    std::string inventoryItemIDsString, laborCostString, statusString;
+    double laborCost;
+    std::istringstream serializedService(record);
+    getline(serializedService, id, ',');
+    getline(serializedService, name, ',');
+    getline(serializedService, inventoryItemIDsString, ',');
+    getline(serializedService, laborCostString, ',');
+    getline(serializedService, statusString, ',');
+    util::Vector<std::string> inventoryItemIDs = getInventoryItemIDsAsVector(inventoryItemIDsString);
+    try
+    {
+        laborCost = std::stod(laborCostString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid labor cost");
+    }
+    util::State status = util::getState(statusString);
     return Factory::getObject<Service>(
-        serializedService.id,
+        id,
-        serializedService.name,
+        name,
         inventoryItemIDs,
-        serializedService.laborCost,
+        laborCost,
-        serializedService.status);
+        status
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for service serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Name,InventoryIDs,LaborCost,Status")
+*/
+std::string Service::getHeaders()
+{
+    return "ID,Name,InventoryIDs,LaborCost,Status";
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/Service.h

@@ -6,6 +6,7 @@ Author: Trenser
 Date: 19-May-2026
 */
 
+
 #pragma once
 #include <string>
 #include "Map.h"
@@ -13,7 +14,6 @@ Date: 19-May-2026
 #include "Enums.h"
 
 class InventoryItem;
-struct SerializedService;
 
 class Service
 {
@@ -40,6 +40,7 @@ public:
     void setRequiredInventoryItems(const util::Map<std::string, InventoryItem*>& requiredInventoryItems);
     void setLaborCost(double laborCost);
     void setState(util::State status);
-    SerializedService serialize() const;
+    std::string serialize() const;
-    static Service* deserialize(const SerializedService&);
+    static Service* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ServiceBooking.cpp

@@ -6,10 +6,8 @@ Description: Implementation file containing the method definitions of the
 Author: Trenser
 Date:19-May-2026
 */
-
 #include <stdexcept>
 #include <sstream>
-#include "SerializedRecords.h"
 #include "ServiceBooking.h"
 #include "Service.h"
 #include "Enums.h"
@@ -30,8 +28,7 @@ ServiceBooking::ServiceBooking()
     m_customer(nullptr),
     m_assignedTechnician(nullptr),
     m_status(util::ServiceJobStatus::PENDING),
-    m_discountPercentage(0.0) {
+    m_discountPercentage(0.0) {}
-}
 
 /*
 Function: ServiceBooking
@@ -440,46 +437,84 @@ static util::Vector<std::string> getServiceIDsAsVector(const std::string& servic
 
 /*
 Function: serialize
-Description: Serializes the ServiceBooking object into a SerializedServiceBooking record.
+Description: Serializes the service booking into a CSV-formatted string.
 Parameters:
     - None
 Returns:
-    - SerializedServiceBooking: Serialized representation of the service booking
+    - std::string: Serialized booking record
 */
-SerializedServiceBooking ServiceBooking::serialize() const
+std::string ServiceBooking::serialize() const
 {
-    SerializedServiceBooking serialized = {};
+    std::ostringstream serializedBooking;
-    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    serializedBooking << m_id << ','
-    strcpy_s(serialized.serviceIDs, sizeof(serialized.serviceIDs), getServiceIDsAsString(m_serviceIDs).c_str());
+        << util::getServiceJobStatusString(m_status) << ','
-    strcpy_s(serialized.customerId, sizeof(serialized.customerId), m_customerId.c_str());
+        << getServiceIDsAsString(m_serviceIDs) << ','
-    strcpy_s(serialized.vehicleNumber, sizeof(serialized.vehicleNumber), m_vehicleNumber.c_str());
+        << m_customerId << ','
-    strcpy_s(serialized.vehicleBrand, sizeof(serialized.vehicleBrand), m_vehicleBrand.c_str());
+        << m_vehicleNumber << ','
-    strcpy_s(serialized.vehicleModel, sizeof(serialized.vehicleModel), m_vehicleModel.c_str());
+        << m_vehicleBrand << ','
-    strcpy_s(serialized.assignedTechnicianId, sizeof(serialized.assignedTechnicianId), m_assignedTechnicianId.c_str());
+        << m_vehicleModel << ','
-    serialized.status = m_status;
+        << m_assignedTechnicianId << ','
-    serialized.discountPercentage = m_discountPercentage;
+        << m_discountPercentage << ',';
-    return serialized;
+    return serializedBooking.str();
 }
 
 /*
 Function: deserialize
-Description: Deserializes a SerializedServiceBooking record into a ServiceBooking object.
+Description: Deserializes a CSV-formatted string into a ServiceBooking object.
 Parameters:
-    - serializedServiceBooking: const SerializedServiceBooking&, serialized service booking record
+    - record: const std::string&, serialized booking record
 Returns:
     - ServiceBooking*: Pointer to the deserialized ServiceBooking object
+Throws:
+    - std::runtime_error if discount percentage parsing fails
 */
-ServiceBooking* ServiceBooking::deserialize(const SerializedServiceBooking& serializedServiceBooking)
+ServiceBooking* ServiceBooking::deserialize(const std::string& record)
 {
-    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serializedServiceBooking.serviceIDs);
+    std::string id, customerId, vehicleNumber, vehicleBrand, vehicleModel, assignedTechnicianId;
+    std::string serviceJobStatusString, serviceIDsString, discountPercentageString;
+    double discountPercentage;
+    std::istringstream serializedBooking(record);
+    getline(serializedBooking, id, ',');
+    getline(serializedBooking, serviceJobStatusString, ',');
+    getline(serializedBooking, serviceIDsString, ',');
+    getline(serializedBooking, customerId, ',');
+    getline(serializedBooking, vehicleNumber, ',');
+    getline(serializedBooking, vehicleBrand, ',');
+    getline(serializedBooking, vehicleModel, ',');
+    getline(serializedBooking, assignedTechnicianId, ',');
+    getline(serializedBooking, discountPercentageString, ',');
+    util::Vector<std::string> serviceIDs = getServiceIDsAsVector(serviceIDsString);
+    try
+    {
+        discountPercentage = std::stod(discountPercentageString);
+    }
+    catch (...)
+    {
+        throw std::runtime_error("Invalid discount percentage");
+    }
+    util::ServiceJobStatus status = util::getServiceJobStatus(serviceJobStatusString);
     return Factory::getObject<ServiceBooking>(
-        serializedServiceBooking.id,
+        id,
-        serializedServiceBooking.status,
+        status,
         serviceIDs,
-        serializedServiceBooking.customerId,
+        customerId,
-        serializedServiceBooking.vehicleNumber,
+        vehicleNumber,
-        serializedServiceBooking.vehicleBrand,
+        vehicleBrand,
-        serializedServiceBooking.vehicleModel,
+        vehicleModel,
-        serializedServiceBooking.assignedTechnicianId,
+        assignedTechnicianId,
-        serializedServiceBooking.discountPercentage);
+        discountPercentage
+    );
+}
+
+/*
+Function: getHeaders
+Description: Retrieves the CSV headers for service booking serialization.
+Parameters:
+    - None
+Returns:
+    - std::string: Header string ("ID,Status,ServiceIDs,CustomerID,VehicleNumber,VehicleBrand,VehicleModel,AssignedTechnicianID,DiscountPercentage")
+*/
+std::string ServiceBooking::getHeaders()
+{
+    return "ID,Status,ServiceIDs,CustomerID,VehicleNumber,VehicleBrand,VehicleModel,AssignedTechnicianID,DiscountPercentage";
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/ServiceBooking.h

@@ -6,7 +6,6 @@ Description: Header file declaring the ServiceBooking class, which represents
 Author: Trenser
 Date:19-May-2026
 */
-
 #pragma once
 #include <string>
 #include "Map.h"
@@ -15,7 +14,6 @@ Date:19-May-2026
 
 class Service;
 class User;
-struct SerializedServiceBooking;
 
 class ServiceBooking
 {
@@ -80,6 +78,7 @@ public:
     void setAssignedTechnicianId(const std::string& assignedTechnicianId);
     void setAssignedTechnician(User* assignedTechnician);
     void setDiscountPercentage(double discountPercentage);
-    SerializedServiceBooking serialize() const;
+    std::string serialize() const;
-    static ServiceBooking* deserialize(const SerializedServiceBooking&);
+    static ServiceBooking* deserialize(const std::string&);
+    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/User.cpp

@@ -8,6 +8,7 @@ Date: 19-May-2026
 */
 
 #include <sstream>
+#include "SerializedRecords.h"
 #include "User.h"
 #include "Notification.h"
 #include "Enums.h"
@@ -28,7 +29,8 @@ Returns:
 User::User()
     : m_id("USR" + std::to_string(++m_uid)),
     m_type(util::UserType::CUSTOMER),
-    m_status(util::State::ACTIVE) {}
+    m_status(util::State::ACTIVE) {
+}
 
 /*
 Function: User
@@ -51,7 +53,8 @@ User::User(const std::string& userName, const std::string& password, const std::
     m_phone(phone),
     m_email(email),
     m_type(role),
-    m_status(util::State::ACTIVE) {}
+    m_status(util::State::ACTIVE) {
+}
 
 /*
 Function: User (parameterized constructor with ID)
@@ -324,68 +327,43 @@ void User::setState(util::State status)
 
 /*
 Function: serialize
-Description: Serializes the user into a CSV-formatted string.
+Description: Serializes the User object into a SerializedUser record.
 Parameters:
     - None
 Returns:
-    - std::string: Serialized user record
+    - SerializedUser: Serialized representation of the user
 */
-std::string User::serialize() const
+SerializedUser User::serialize() const
 {
-    std::ostringstream serializedUser;
+    SerializedUser serialized = {};
-    serializedUser << m_id << ','
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
-        << m_userName << ','
+    strcpy_s(serialized.username, sizeof(serialized.username), m_userName.c_str());
-        << m_password << ','
+    strcpy_s(serialized.password, sizeof(serialized.password), m_password.c_str());
-        << m_name << ','
+    strcpy_s(serialized.name, sizeof(serialized.name), m_name.c_str());
-        << m_phone << ','
+    strcpy_s(serialized.phone, sizeof(serialized.phone), m_phone.c_str());
-        << m_email << ','
+    strcpy_s(serialized.email, sizeof(serialized.email), m_email.c_str());
-        << util::getUserTypeString(m_type) << ','
+    serialized.userType = m_type;
-        << util::getStateString(m_status);
+    serialized.status = m_status;
-    return serializedUser.str();
+    return serialized;
 }
 
 /*
 Function: deserialize
-Description: Deserializes a CSV-formatted string into a User object.
+Description: Deserializes a SerializedUser record into a User object.
 Parameters:
-    - record: const std::string&, serialized user record
+    - serializedUser: const SerializedUser&, serialized user record
 Returns:
     - User*: Pointer to the deserialized User object
 */
-User* User::deserialize(const std::string& record)
+User* User::deserialize(const SerializedUser& serializedUser)
 {
-    std::string id, name, username, phone, password, email;
+    return Factory::getObject<User>(
-    std::string userTypeString, stateString;
+        serializedUser.id,
-    std::istringstream serializedUser(record);
+        serializedUser.username,
-    getline(serializedUser, id, ',');
+        serializedUser.password,
-    getline(serializedUser, username, ',');
+        serializedUser.name,
-    getline(serializedUser, password, ',');
+        serializedUser.phone,
-    getline(serializedUser, name, ',');
+        serializedUser.email,
-    getline(serializedUser, phone, ',');
+        serializedUser.userType,
-    getline(serializedUser, email, ',');
+        serializedUser.status);
-    getline(serializedUser, userTypeString, ',');
-    getline(serializedUser, stateString);
-    util::UserType userType = util::getUserType(userTypeString);
-    util::State status = util::getState(stateString);
-    return Factory::getObject<User>(id,
-        username,
-        password,
-        name,
-        phone,
-        email,
-        userType,
-        status);
-}
-
-/*
-Function: getHeaders
-Description: Retrieves the CSV headers for user serialization.
-Parameters:
-    - None
-Returns:
-    - std::string: Header string ("ID,Username,Password,Name,Phone,Email,UserType,UserStatus")
-*/
-std::string User::getHeaders()
-{
-    return "ID,Username,Password,Name,Phone,Email,UserType,UserStatus";
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/User.h

@@ -14,6 +14,7 @@ Date: 19-May-2026
 #include "Enums.h"
 
 class Notification;
+struct SerializedUser;
 
 class User : public Observer
 {
@@ -51,7 +52,6 @@ public:
     void addNotification(Notification* notification) override;
     void setRole(util::UserType role);
     void setState(util::State status);
-    std::string serialize() const;
+    SerializedUser serialize() const;
-    static User* deserialize(const std::string&);
+    static User* deserialize(const SerializedUser& serializedUser);
-    static std::string getHeaders();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.cpp

@@ -20,6 +20,9 @@ Date:19-May-2026
 #include "UserManagementService.h"
 #include "Vector.h"
 #include "Validator.h"
+#include "Utility.h"
+#include "TrackedRecord.h"
+#include "DataStoreLockGuard.h"
 
 /*
 Function: ensureAdminExists
@@ -31,12 +34,13 @@ Return type: void
 */
 void UserManagementService::ensureAdminExists()
 {
+	DataStoreLockGuard lock(m_dataStore);
 	auto& usersMap = m_dataStore.getUsers();
 	int usersMapSize = usersMap.getSize();
 	bool isAdminFound = false;
 	for (int index = 0; index < usersMapSize; index++)
 	{
-		User* user = usersMap.getValueAt(index);
+		User* user = usersMap.getValueAt(index).data;
 		if (user && user->getUserType() == util::UserType::ADMIN)
 		{
 			isAdminFound = true;
@@ -73,7 +77,9 @@ void UserManagementService::createUser(const std::string& username, const std::s
 	InventoryManagementService inventoryManagementService;
 	PaymentManagementService paymentManagementService;
 	ServiceManagementService serviceManagementService;
-	auto& usersMap = m_dataStore.getUsers();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	auto usersMap = util::getObjects(trackedUsersMap);
 	if (util::isUsernameDuplicate(username, usersMap))
 	{
 		throw std::runtime_error("Username already exists");
@@ -87,13 +93,14 @@ void UserManagementService::createUser(const std::string& username, const std::s
 		throw std::runtime_error("Phone already exists");
 	}
 	User* newUser = Factory::getObject<User>(username, password, name, phone, email, type);
-	usersMap.insert(newUser->getId(), newUser);
+	trackedUsersMap.insert(newUser->getId(), util::createNewRecord(newUser));
 	paymentManagementService.attach(newUser);
 	serviceManagementService.attach(newUser);
 	if (newUser->getUserType() == util::UserType::ADMIN)
 	{
 		inventoryManagementService.attach(newUser);
 	}
+	m_dataStore.saveUsers();
 }
 
 /*
@@ -107,19 +114,24 @@ Return type: void
 */
 void UserManagementService::updateUserDetails(const std::string& userID, const std::string& email, const std::string& phone)
 {
-	auto& usersMap = m_dataStore.getUsers();
+	DataStoreLockGuard lock(m_dataStore);
-	int index = usersMap.find(userID);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	auto usersMap = util::getObjects(trackedUsersMap);
+	int index = trackedUsersMap.find(userID);
 	if (index == -1)
 	{
 		throw std::runtime_error("User does not exist!\n");
 	}
-	User* user = usersMap.getValueAt(index);
+	User* user = trackedUsersMap.getValueAt(index).data;
+	bool isModified = false;
 	if (email != user->getEmail())
 	{
 		if (util::isEmailDuplicate(email, usersMap))
 		{
 			throw std::runtime_error("Email already exists!\n");
 		}
+		user->setEmail(email);
+		isModified = true;
 	}
 	if (phone != user->getPhone())
 	{
@@ -127,9 +139,14 @@ void UserManagementService::updateUserDetails(const std::string& userID, const s
 		{
 			throw std::runtime_error("Phone number already exists!\n");
 		}
+		user->setPhone(phone);
+		isModified = true;
+	}
+	if (isModified)
+	{
+		trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
+		m_dataStore.saveUsers();
 	}
-	user->setEmail(email);
-	user->setPhone(phone);
 }
 
 /*
@@ -144,12 +161,13 @@ Throws:
 */
 util::Vector<Notification*> UserManagementService::getUserNotifications(const std::string& userID)
 {
-	auto& usersMap = m_dataStore.getUsers();
+	DataStoreLockGuard lock(m_dataStore);
-	if (usersMap.find(userID) == -1)
+	auto& trackedUsersMap = m_dataStore.getUsers(); 
+	if (trackedUsersMap.find(userID) == -1)
 	{
 		throw std::runtime_error("No user found with given UserID");
 	}
-	User* user = usersMap[userID];
+	User* user = trackedUsersMap[userID].data;
 	if (user)
 	{
 		auto& notifications = user->getNotifications();
@@ -169,97 +187,41 @@ util::Vector<Notification*> UserManagementService::getUserNotifications(const st
 
 /*
 Function: deleteNotification
-Description: Deletes a specific notification associated with a given user ID.
+Description: Marks a specific notification associated with a given user
+			 as inactive.
 Parameters:
 	- notificationID: The unique ID of the notification to be deleted.
 	- userID: The unique ID of the user whose notification is to be deleted.
 Returns:
 	- void
 Throws:
-	- std::runtime_error if no user is found with the given UserID or if no notification is found with the given NotificationID.
+	- std::runtime_error if no user is found with the given UserID or
+	  if no notification is found with the given NotificationID.
 */
 void UserManagementService::deleteNotification(const std::string& notificationID, const std::string& userID)
 {
-	auto& usersMap = m_dataStore.getUsers();
+	DataStoreLockGuard lock(m_dataStore);
-	if (usersMap.find(userID) == -1)
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	auto& trackedNotificationsMap = m_dataStore.getNotifications();
+	int userIndex = trackedUsersMap.find(userID);
+	if (userIndex == -1)
 	{
 		throw std::runtime_error("No user found with given UserID");
 	}
-	User* user = usersMap[userID];
+	User* user = trackedUsersMap.getValueAt(userIndex).data;
 	auto& notifications = user->getNotifications();
 	if (notifications.find(notificationID) == -1)
 	{
 		throw std::runtime_error("No notification found with given NotificationID");
 	}
-	notifications.remove(notificationID);
+	int notificationIndex = trackedNotificationsMap.find(notificationID);
-}
+	if (notificationIndex == -1)
-
+	{
-/*
+		throw std::runtime_error("No notification found with given NotificationID");
-Function: loadUsers
+	}
-Description: Loads users and notifications from persistent storage into the datastore.
+	notifications[notificationID]->setState(util::State::INACTIVE);
-             Validates that each notification’s recipient exists and attaches the
+	trackedNotificationsMap.getValueAt(notificationIndex).state = RecordState::MODIFIED;
-             notification to the corresponding user.
+	m_dataStore.saveNotifications();
-Parameters:
-    - None
-Returns:
-    - void
-Throws:
-    - std::runtime_error if a notification recipient user ID is invalid
-*/
-void UserManagementService::loadUsers()
-{
-    util::FileManager<User> userFileManager(config::file::USER_FILE);
-    util::FileManager<Notification> notificationFileManager(config::file::NOTIFICATION_FILE);
-    auto& users = m_dataStore.getUsers();
-    auto usersMap = userFileManager.load();
-    auto notificationsMap = notificationFileManager.load();
-    int numberOfUsers = usersMap.getSize();
-    int numberOfNotifications = notificationsMap.getSize();
-    for (int index = 0; index < numberOfUsers; index++)
-    {
-        users[usersMap.getKeyAt(index)] = usersMap.getValueAt(index);
-    }
-    for (int index = 0; index < numberOfNotifications; index++)
-    {
-        Notification* notification = notificationsMap.getValueAt(index);
-        const std::string& recipientUserId = notification->getRecipientUserId();
-        int userIndex = users.find(recipientUserId);
-        if (userIndex == -1)
-        {
-            throw std::runtime_error("Invalid recipient user ID");
-        }
-        User* user = users.getValueAt(userIndex);
-        user->addNotification(notification);
-    }
-}
-
-/*
-Function: saveUsers
-Description: Saves users and their notifications from the datastore to persistent storage.
-             Collects notifications from all users into a single map before saving.
-Parameters:
-    - None
-Returns:
-    - void
-*/
-void UserManagementService::saveUsers()
-{
-    util::FileManager<User> userFileManager(config::file::USER_FILE);
-    util::FileManager<Notification> notificationFileManager(config::file::NOTIFICATION_FILE);
-    auto& users = m_dataStore.getUsers();
-    util::Map<std::string, Notification*> notifications;
-    for (int userIndex = 0; userIndex < users.getSize(); userIndex++)
-    {
-        User* user = users.getValueAt(userIndex);
-        auto& userNotifications = user->getNotifications();
-        for (int notificationIndex = 0; notificationIndex < userNotifications.getSize(); notificationIndex++)
-        {
-            notifications[userNotifications.getKeyAt(notificationIndex)] =
-                userNotifications.getValueAt(notificationIndex);
-        }
-    }
-    userFileManager.save(users);
-    notificationFileManager.save(notifications);
 }
 
 /*
@@ -270,7 +232,9 @@ Return type: util::Map<std::string, User*>
 */
 util::Map<std::string, User*> UserManagementService::getUsers()
 {
-	return m_dataStore.getUsers();
+	DataStoreLockGuard lock(m_dataStore);
+	auto users = util::getObjects(m_dataStore.getUsers());
+	return users;
 }
 
 /*
@@ -281,10 +245,12 @@ Return type: User*
 */
 User* UserManagementService::getUser(const std::string& userID)
 {
-	int index = m_dataStore.getUsers().find(userID);
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	int index = trackedUsersMap.find(userID);
 	if (index != -1)
 	{
-		return m_dataStore.getUsers().getValueAt(index);
+		return trackedUsersMap.getValueAt(index).data;
 	}
 	return nullptr;
 }
@@ -300,35 +266,53 @@ void UserManagementService::removeUser(const std::string& userID)
 	InventoryManagementService inventoryManagementService;
 	PaymentManagementService paymentManagementService;
 	ServiceManagementService serviceManagementService;
-	int index = m_dataStore.getUsers().find(userID);
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	int index = trackedUsersMap.find(userID);
 	if (index != -1)
 	{
-		User* user = m_dataStore.getUsers().getValueAt(index);
+		User* user = trackedUsersMap.getValueAt(index).data;
 		if (user != nullptr)
 		{
 			if (user->getUserType() == util::UserType::CUSTOMER)
 			{
-				serviceManagementService.cancelCustomerServiceBookings(userID);	
+				serviceManagementService.cancelCustomerServiceBookings(userID);
 			}
 			if (user->getUserType() == util::UserType::TECHNICIAN)
 			{
 				serviceManagementService.cancelTechnicianJobs(userID);
 			}
-			user->setState(util::State::INACTIVE);
 			inventoryManagementService.detach(user);
 			paymentManagementService.detach(user);
 			serviceManagementService.detach(user);
+			user->setState(util::State::INACTIVE);
+			trackedUsersMap.getValueAt(index).state = RecordState::MODIFIED;
+			m_dataStore.saveUsers();
 		}
 	}
 }
 
-util::Map<std::string, User*> UserManagementService::getUsers(util::UserType type)
+/*
+Function: getUsers
+Description: Retrieves all active users of the specified type from
+			 the DataStore.
+Parameters:
+	- type: The user type to filter by
+			(ADMIN, CUSTOMER, or TECHNICIAN).
+Returns:
+	- util::Map<std::string, User*>:
+	  Collection of active users matching the specified type,
+	  keyed by user ID.
+*/
+util::Map<std::string, User*> UserManagementService::getUsers(util::UserType type) 
 {
-	util::Map<std::string, User*>& currentUsers = m_dataStore.getUsers();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedUsersMap = m_dataStore.getUsers();
+	util::Map<std::string, User*> currentUsers = util::getObjects(trackedUsersMap);
 	util::Map<std::string, User*> filteredUsersMap;
-	for (int iterator = 0; iterator < currentUsers.getSize(); iterator++)
+	for (int index = 0; index < currentUsers.getSize(); index++)
 	{
-		User* currentUser = currentUsers.getValueAt(iterator);
+		User* currentUser = currentUsers.getValueAt(index);
 		if (currentUser && currentUser->getState() == util::State::ACTIVE && currentUser->getUserType() == type)
 		{
 			filteredUsersMap.insert(currentUser->getId(), currentUser);

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/UserManagementService.h

@@ -31,6 +31,4 @@ public:
     util::Vector<Notification*> getUserNotifications(const std::string& userID);
     void deleteNotification(const std::string& notificationID, const std::string& userID);
     void ensureAdminExists();
-    void loadUsers();
-    void saveUsers();
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/views/UserInterface.cpp

@@ -27,8 +27,11 @@ void UserInterface::run()
 {
 	try
 	{
-		m_controller.loadSystemData();
+		if (!m_controller.initialize())
-		m_controller.runSystemChecks();
+		{
+			std::cout << "Error: Failed to initialize the system!";
+			return;
+		}
 		bool isMenuActive = true;
 		while (isMenuActive)
 		{
@@ -49,7 +52,7 @@ void UserInterface::run()
 				util::pressEnter();
 			}
 		}
-		m_controller.saveSystemData();
+		m_controller.shutdown();
 	}
 	catch (const std::invalid_argument& exception)
 	{