Implement Service Refactoring

<UserStory> 1958: Service Refactoring </UserStory>
UserStory #1958
<Changes>

1. Added DataStoreLockGuard.h include to project file and InventoryManagementService
   for thread-safe datastore operations.

2. Enhanced DataStore::getUsers to load SerializedUser records, refresh cache,
   and attach notifications with recipient validation.

3. Enhanced DataStore::getInventoryItems to load SerializedInventoryItem records
   and refresh cache for tracked inventory items.

4. Refactored InventoryManagementService::sendLowStockAlerts to use tracked
   inventory and user maps with DataStoreLockGuard, ensuring safe access.

5. Removed legacy observer management, load/save inventory items, and related
   persistence functions from InventoryManagementService.

6. Updated InventoryManagementService::addInventoryItem to insert new records
   into tracked inventory map and persist changes via saveInventoryItems.

7. Updated InventoryManagementService::addInventoryItemStock to validate item
   existence, update quantity, mark record as MODIFIED, and persist changes.

8. Refactored InventoryManagementService::getInventoryItems to return object
   map extracted from tracked records with DataStoreLockGuard.

9. Updated InventoryManagementService::removeInventoryItem to validate item ID,
   mark state as INACTIVE, set record state to MODIFIED, and persist changes.

10. Updated InventoryManagementService::getInventoryItem to safely retrieve
    inventory items from tracked records with error handling.

</Changes>

<Test>

N/A

</Test>

<Review>

Sreeja Reghukumar

</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/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;
 }
 
@@ -280,6 +296,8 @@ Returns:
 */
 util::Map<std::string, TrackedRecord<InventoryItem>>& DataStore::getInventoryItems()
 {
+    auto inventoryItems = loadRecords<InventoryItem, SerializedInventoryItem>(m_inventoryItems);
+    refreshCache(m_inventoryItemCache, inventoryItems);
     return m_inventoryItemCache;
 }
 
@@ -419,6 +437,7 @@ Returns:
 */
 void DataStore::saveInventoryItems()
 {
+    saveRecords<InventoryItem, SerializedInventoryItem>(m_inventoryItems, m_inventoryItemCache);
 }
 
 /*

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/models/InventoryItem.cpp

@@ -8,6 +8,7 @@ Date: 19-May-2026
 
 #include <sstream>
 #include <stdexcept>
+#include "SerializedRecords.h"
 #include "Factory.h"
 #include "StringHelper.h"
 #include "InventoryItem.h"
@@ -27,7 +28,8 @@ InventoryItem::InventoryItem()
     : m_id("IIM" + std::to_string(++m_uid)),
     m_quantity(0),
     m_status(util::State::ACTIVE),
-    m_price(0.0) {}
+    m_price(0.0) {
+}
 
 /*
 Function: InventoryItem
@@ -45,7 +47,8 @@ InventoryItem::InventoryItem(const std::string& partName, int quantity, double p
     m_partName(partName),
     m_quantity(quantity),
     m_status(util::State::ACTIVE),
-    m_price(price) {}
+    m_price(price) {
+}
 
 /*
 Function: InventoryItem (parameterized constructor with ID)
@@ -206,73 +209,37 @@ void InventoryItem::setState(util::State status)
 
 /*
 Function: serialize
-Description: Serializes the inventory item into a CSV-formatted string.
+Description: Serializes the InventoryItem object into a SerializedInventoryItem record.
 Parameters:
     - None
 Returns:
-    - std::string: Serialized inventory item record
+    - SerializedInventoryItem: Serialized representation of the inventory item
 */
-std::string InventoryItem::serialize() const
+SerializedInventoryItem InventoryItem::serialize() const
 {
-    std::ostringstream serializedInventoryItem;
-    serializedInventoryItem << m_id << ','
-        << m_partName << ','
-        << m_quantity << ','
-        << m_price << ','
-        << util::getStateString(m_status);
-    return serializedInventoryItem.str();
+    SerializedInventoryItem serialized = {};
+    strcpy_s(serialized.id, sizeof(serialized.id), m_id.c_str());
+    strcpy_s(serialized.partName, sizeof(serialized.partName), m_partName.c_str());
+    serialized.quantity = m_quantity;
+    serialized.price = m_price;
+    serialized.status = m_status;
+    return serialized;
 }
 
 /*
 Function: deserialize
-Description: Deserializes a CSV-formatted string into an InventoryItem object.
+Description: Deserializes a SerializedInventoryItem record into an InventoryItem object.
 Parameters:
-    - record: const std::string&, serialized inventory item record
+    - serializedInventoryItem: const SerializedInventoryItem&, serialized inventory item record
 Returns:
     - InventoryItem*: Pointer to the deserialized InventoryItem object
-Throws:
-    - std::runtime_error if data is invalid
 */
-InventoryItem* InventoryItem::deserialize(const std::string& record)
+InventoryItem* InventoryItem::deserialize(const SerializedInventoryItem& serializedInventoryItem)
 {
-    std::string id, partName;
-    std::string quantityString, priceString, statusString;
-    int quantity;
-    double price;
-    std::istringstream serializedInventoryItem(record);
-    getline(serializedInventoryItem, id, ',');
-    getline(serializedInventoryItem, partName, ',');
-    getline(serializedInventoryItem, quantityString, ',');
-    getline(serializedInventoryItem, priceString, ',');
-    getline(serializedInventoryItem, statusString, ',');
-    try
-    {
-        quantity = std::stoi(quantityString);
-        price = std::stod(priceString);
-    }
-    catch (...)
-    {
-        throw std::runtime_error("Invalid inventory item data");
-    }
-    util::State status = util::getState(statusString);
     return Factory::getObject<InventoryItem>(
-        id,
-        partName,
-        quantity,
-        price,
-        status
-    );
-}
-
-/*
-Function: getHeaders
-Description: Retrieves the CSV headers for inventory item serialization.
-Parameters:
-    - None
-Returns:
-    - std::string: Header string ("ID,PartName,Quantity,Price,Status")
-*/
-std::string InventoryItem::getHeaders()
-{
-    return "ID,PartName,Quantity,Price,Status";
+        serializedInventoryItem.id,
+        serializedInventoryItem.partName,
+        serializedInventoryItem.quantity,
+        serializedInventoryItem.price,
+        serializedInventoryItem.status);
 }

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/models/InventoryItem.h

@@ -6,11 +6,12 @@ Author: Trenser
 Date: 19-May-2026
 */
 
-
 #pragma once
 #include <string>
 #include "Enums.h"
 
+struct SerializedInventoryItem;
+
 class InventoryItem
 {
 private:
@@ -34,7 +35,6 @@ public:
     void setQuantity(int quantity);
     void setPrice(double price);
     void setState(util::State status);
-    std::string serialize() const;
-    static InventoryItem* deserialize(const std::string&);
-    static std::string getHeaders();
+    SerializedInventoryItem serialize() const;
+    static InventoryItem* deserialize(const SerializedInventoryItem&);
 };

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.cpp

@@ -19,7 +19,7 @@ Date: 22-May-2026
 #include "User.h"
 #include "Utility.h"
 #include "Vector.h"
-
+#include "DataStoreLockGuard.h"
 
 util::Map<std::string, User*> InventoryManagementService::m_observers{};
 
@@ -58,18 +58,19 @@ Returns:
 */
 void InventoryManagementService::sendLowStockAlerts()
 {
-	auto& inventoryItems = m_dataStore.getInventoryItems();
-	if (inventoryItems.isEmpty())
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemsMap = m_dataStore.getInventoryItems();
+	auto& trackedUserMap = m_dataStore.getUsers();
+	if (trackedInventoryItemsMap.isEmpty())
 	{
 		return;
 	}
-	int inventoryItemsSize = inventoryItems.getSize();
-	auto& usersMap = m_dataStore.getUsers();
-	int usersMapSize = usersMap.getSize();
+	int inventoryItemsSize = trackedInventoryItemsMap.getSize();
+	int usersMapSize = trackedUserMap.getSize();
 	util::Vector<User*> adminUsers;
 	for (int index = 0; index < usersMapSize; index++)
 	{
-		User* user = usersMap.getValueAt(index);
+		User* user = trackedUserMap.getValueAt(index).data;
 		if (user->getUserType() == util::UserType::ADMIN)
 		{
 			adminUsers.push_back(user);
@@ -82,7 +83,7 @@ void InventoryManagementService::sendLowStockAlerts()
 	}
 	for (int index = 0; index < inventoryItemsSize; index++)
 	{
-		InventoryItem* inventoryItem = inventoryItems.getValueAt(index);
+		InventoryItem* inventoryItem = trackedInventoryItemsMap.getValueAt(index).data;
 		if (inventoryItem && inventoryItem->getQuantity() < config::threshold::INVENTORY_LOW_STOCK_THRESHOLD)
 		{
 			sendLowStockAlertsToAdmins(*this, inventoryItem, adminUsers);
@@ -90,95 +91,6 @@ void InventoryManagementService::sendLowStockAlerts()
 	}
 }
 
-/*
-Function: getObserverIDs
-Description: Retrieves the IDs of all observers currently attached to the
-			 InventoryManagementService.
-Parameters:
-	- None
-Returns:
-	- util::Vector<std::string>: Vector of observer user IDs
-*/
-util::Vector<std::string> InventoryManagementService::getObserverIDs()
-{
-	util::Vector<std::string> observerIDs;
-	int numberOfObservers = m_observers.getSize();
-	for (int index = 0; index < numberOfObservers; index++)
-	{
-		User* observer = m_observers.getValueAt(index);
-		if (observer)
-		{
-			observerIDs.push_back(observer->getId());
-		}
-	}
-	return observerIDs;
-}
-
-/*
-Function: loadInventoryItems
-Description: Loads inventory items from persistent storage into the datastore.
-			 Uses FileManager to deserialize inventory items from the configured file.
-Parameters:
-	- None
-Returns:
-	- void
-*/
-void InventoryManagementService::loadInventoryItems()
-{
-	util::FileManager<InventoryItem> inventoryItemFileManager(config::file::INVENTORYITEM_FILE);
-	auto& inventoryItems = m_dataStore.getInventoryItems();
-	auto inventoryItemsMap = inventoryItemFileManager.load();
-	int numberOfInventoryItems = inventoryItemsMap.getSize();
-	for (int index = 0; index < numberOfInventoryItems; index++)
-	{
-		inventoryItems[inventoryItemsMap.getKeyAt(index)] = inventoryItemsMap.getValueAt(index);
-	}
-}
-
-/*
-Function: saveInventoryItems
-Description: Saves inventory items from the datastore to persistent storage.
-			 Uses FileManager to serialize inventory items into the configured file.
-Parameters:
-	- None
-Returns:
-	- void
-*/
-void InventoryManagementService::saveInventoryItems()
-{
-	util::FileManager<InventoryItem> inventoryItemFileManager(config::file::INVENTORYITEM_FILE);
-	auto& inventoryItems = m_dataStore.getInventoryItems();
-	inventoryItemFileManager.save(inventoryItems);
-}
-
-/*
-Function: loadObservers
-Description: Loads observer IDs from persistent storage and attaches corresponding
-			 users as observers to the InventoryManagementService.
-Parameters:
-	- None
-Returns:
-	- void
-*/
-void InventoryManagementService::loadObservers()
-{
-	util::loadObservers(config::file::INVENTORYMANAGEMENTOBSERVERS, this, m_dataStore);
-}
-
-/*
-Function: saveObservers
-Description: Saves the current observer IDs of the InventoryManagementService
-			 to persistent storage for future retrieval.
-Parameters:
-	- None
-Returns:
-	- void
-*/
-void InventoryManagementService::saveObservers()
-{
-	util::saveObservers(config::file::INVENTORYMANAGEMENTOBSERVERS, this);
-}
-
 /*
 Function: addInventoryItem
 Description: Creates a new inventory item using the Factory and inserts it
@@ -190,8 +102,11 @@ Return type: void
 */
 void InventoryManagementService::addInventoryItem(const std::string& partName, int quantity, double price)
 {
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
     InventoryItem* newItem = Factory::getObject<InventoryItem>(partName, quantity, price);
-    m_dataStore.getInventoryItems().insert(newItem->getId(), newItem);
+	trackedInventoryItemMap.insert(newItem->getId(), util::createNewRecord(newItem));
+	m_dataStore.saveInventoryItems();
 }
 
 /*
@@ -203,16 +118,22 @@ Return type: void
 */
 void InventoryManagementService::addInventoryItemStock(const std::string& selectedItemId, int quantity)
 {
-    int index = m_dataStore.getInventoryItems().find(selectedItemId);
-    if (index != -1)
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+	int index = trackedInventoryItemMap.find(selectedItemId);
+	if (index == -1)
 	{
-        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
-        if (item != nullptr)
+		throw std::runtime_error("Inventory update failed: Item ID '" + selectedItemId + "' not found.");
+	}
+	InventoryItem* item = trackedInventoryItemMap.getValueAt(index).data;
+	if (item == nullptr)
 	{
+		throw std::runtime_error("Inventory update failed. Item does not exist.\n");
+	}
 	int totalQuantity = item->getQuantity() + quantity;
 	item->setQuantity(totalQuantity);
-        }
-    }
+	trackedInventoryItemMap.getValueAt(index).state = RecordState::MODIFIED;
+	m_dataStore.saveInventoryItems();
 }
 
 /*
@@ -223,7 +144,10 @@ Return type: util::Map<std::string, InventoryItem*>
 */
 util::Map<std::string, InventoryItem*> InventoryManagementService::getInventoryItems()
 {
-	return m_dataStore.getInventoryItems();
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+	auto inventoryMap = util::getObjects(trackedInventoryItemMap);
+	return inventoryMap;
 }
 
 /*
@@ -234,15 +158,21 @@ Return type: void
 */
 void InventoryManagementService::removeInventoryItem(const std::string& inventoryItemID)
 {
-    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
-    if (index != -1)
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+	int index = trackedInventoryItemMap.find(inventoryItemID);
+	if (index == -1)
 	{
-        InventoryItem* item = m_dataStore.getInventoryItems().getValueAt(index);
-        if (item != nullptr)
+		throw std::runtime_error("Inventory removal failed: Item ID '" + inventoryItemID + "' not found.");
+	}
+	InventoryItem* item = trackedInventoryItemMap.getValueAt(index).data;
+	if (item == nullptr)
 	{
+		throw std::runtime_error("Inventory removal failed: Item ID does not exist.");
+	}
 	item->setState(util::State::INACTIVE);
-        }
-    }
+	trackedInventoryItemMap.getValueAt(index).state = RecordState::MODIFIED;
+	m_dataStore.saveInventoryItems();
 }
 
 /*
@@ -253,12 +183,19 @@ Return type: InventoryItem*
 */
 InventoryItem* InventoryManagementService::getInventoryItem(const std::string& inventoryItemID)
 {
-    int index = m_dataStore.getInventoryItems().find(inventoryItemID);
-    if (index != -1)
+	DataStoreLockGuard lock(m_dataStore);
+	auto& trackedInventoryItemMap = m_dataStore.getInventoryItems();
+    int index = trackedInventoryItemMap.find(inventoryItemID);
+    if (index == -1)
     {
-        return m_dataStore.getInventoryItems().getValueAt(index);
-    }
 		return nullptr;
+    }
+	InventoryItem* inventoryItem = trackedInventoryItemMap.getValueAt(index).data;
+	if (inventoryItem == nullptr)
+	{
+		throw std::runtime_error("Item ID does not exist.");
+	}
+	return inventoryItem;
 }
 
 /*

Trenser.VehicleServiceSystem/Trenser.VehicleServiceSystem/services/InventoryManagementService.h

@@ -33,8 +33,6 @@ public:
     void sendNotification(User* user, const std::string& title, const std::string& message) override;
     void attach(User* user) override;
     void detach(User* user) override;
-    void loadInventoryItems();
-    void saveInventoryItems();
     void loadObservers();
     void saveObservers();
 };