Integrate XtraSysStatObs with SystemStatusObserver

Use SystemStatusObserver to subscribe for dataitems in
XtraSystemStatusObserver.

Change-Id: Ib1828b9025c9c5bb5194a36014249472ed3f6f9e
CRs-Fixed: 2093290

9 files changed, 914 insertions, 790 deletions

diff --git a/core/SystemStatus.cpp b/core/SystemStatus.cpp
index dc03604..52d28c7 100644
--- a/core/SystemStatus.cpp
+++ b/core/SystemStatus.cpp
@@ -37,6 +37,7 @@
 #include <platform_lib_log_util.h>
 #include <MsgTask.h>
 #include <loc_nmea.h>
+#include <DataItemsFactoryProxy.h>
 #include <SystemStatus.h>
 #include <SystemStatusOsObserver.h>
 
@@ -1212,7 +1213,8 @@ IOsObserver* SystemStatus::getOsObserver()
 }
 
 SystemStatus::SystemStatus(const MsgTask* msgTask) :
-    mSysStatusObsvr(msgTask)
+    mSysStatusObsvr(msgTask),
+    mConnected(false)
 {
     int result = 0;
     ENTRY_LOG ();
@@ -1414,6 +1416,28 @@ bool SystemStatus::setPositionFailure(const SystemStatusPQWS1& nmea)
 }
 
 /******************************************************************************
+ SystemStatus - storing dataitems
+******************************************************************************/
+bool SystemStatus::setNetworkInfo(IDataItemCore* dataitem)
+{
+    SystemStatusNetworkInfo* data = reinterpret_cast<SystemStatusNetworkInfo*>(dataitem);
+    SystemStatusNetworkInfo s(data->mType,data->mTypeName,data->mSubTypeName,
+                              data->mAvailable,data->mConnected,data->mRoaming);
+    s.dump();
+    mConnected = data->mConnected;
+
+    if (!mCache.mNetworkInfo.empty() && mCache.mNetworkInfo.back().equals(s)) {
+        mCache.mNetworkInfo.back().mUtcReported = s.mUtcReported;
+    } else {
+        mCache.mNetworkInfo.push_back(s);
+        if (mCache.mNetworkInfo.size() > maxNetworkInfo) {
+            mCache.mNetworkInfo.erase(mCache.mNetworkInfo.begin());
+        }
+    }
+    return true;
+}
+
+/******************************************************************************
 @brief      API to set report data into internal buffer
 
 @param[In]  data pointer to the NMEA string
@@ -1534,6 +1558,26 @@ bool SystemStatus::eventPosition(const UlpLocation& location,
 }
 
 /******************************************************************************
+@brief      API to set report DataItem event into internal buffer
+
+@param[In]  DataItem
+
+@return     true when successfully done
+******************************************************************************/
+bool SystemStatus::eventDataItemNotify(IDataItemCore* dataitem)
+{
+    pthread_mutex_lock(&mMutexSystemStatus);
+    switch(dataitem->getId())
+    {
+        case NETWORKINFO_DATA_ITEM_ID:
+            setNetworkInfo(dataitem);
+            break;
+    }
+    pthread_mutex_unlock(&mMutexSystemStatus);
+    return true;
+}
+
+/******************************************************************************
 @brief      API to get report data into a given buffer
 
 @param[In]  reference to report buffer
@@ -1712,5 +1756,33 @@ bool SystemStatus::setDefaultReport(void)
     return true;
 }
 
+/******************************************************************************
+@brief      API to handle connection status update event from GnssRil
+
+@param[In]  Connection status
+
+@return     true when successfully done
+******************************************************************************/
+bool SystemStatus::eventConnectionStatus(bool connected, uint8_t type)
+{
+    if (connected != mConnected) {
+        mConnected = connected;
+
+        // send networkinof dataitem to systemstatus observer clients
+        SystemStatusNetworkInfo s(type, "", "", false, connected, false);
+        IDataItemCore *networkinfo =
+                DataItemsFactoryProxy::createNewDataItem(NETWORKINFO_DATA_ITEM_ID);
+        if (nullptr == networkinfo) {
+            LOC_LOGE("Unable to create dataitemd");
+            return false;
+        }
+        networkinfo->copy(&s);
+        list<IDataItemCore*> dl(0);
+        dl.push_back(networkinfo);
+        mSysStatusObsvr.notify(dl);
+    }
+    return true;
+}
+
 } // namespace loc_core
 
diff --git a/core/SystemStatus.h b/core/SystemStatus.h
index 8cf75b5..5dc2d9f 100644
--- a/core/SystemStatus.h
+++ b/core/SystemStatus.h
@@ -34,6 +34,7 @@
 #include <vector>
 #include <platform_lib_log_util.h>
 #include <MsgTask.h>
+#include <IDataItemCore.h>
 #include <IOsObserver.h>
 #include <SystemStatusOsObserver.h>
 
@@ -368,18 +369,182 @@ public:
 };
 
 /******************************************************************************
+ SystemStatus report data structure - from DataItem observer
+******************************************************************************/
+class SystemStatusGpsState : public SystemStatusItemBase, public IDataItemCore
+{
+public:
+    inline SystemStatusGpsState() :
+            mEnabled(false) {}
+    inline SystemStatusGpsState(bool enabled) :
+            mEnabled(enabled) {}
+
+    bool mEnabled;
+
+    inline bool equals(SystemStatusGpsState& peer) {
+        return (mEnabled == peer.mEnabled);
+    }
+    inline void dump(void) {
+        LOC_LOGD("GpsState: state=%u", mEnabled);
+    }
+    inline DataItemId getId() {
+        return GPSSTATE_DATA_ITEM_ID;
+    }
+    inline void stringify(string& valueStr) {
+        valueStr.clear();
+        valueStr += "GpsState: enabled=";
+        valueStr += to_string(mEnabled);
+    }
+    inline int32_t copy(IDataItemCore* src, bool* dataItemCopied = nullptr) {
+        SystemStatusGpsState* gpsstate = static_cast<SystemStatusGpsState*>(src);
+        mEnabled = gpsstate->mEnabled;
+        if (dataItemCopied) {
+            *dataItemCopied = true;
+        }
+        return 1;
+    }
+};
+
+class SystemStatusNetworkInfo : public SystemStatusItemBase, public IDataItemCore
+{
+public:
+    inline SystemStatusNetworkInfo() :
+            mType(0),
+            mTypeName(""),
+            mSubTypeName(""),
+            mAvailable(false),
+            mConnected(false),
+            mRoaming(false) {}
+    inline SystemStatusNetworkInfo(
+            uint32_t type,
+            std::string typeName,
+            std::string subTypeName,
+            bool available,
+            bool connected,
+            bool roaming) :
+            mType(type),
+            mTypeName(typeName),
+            mSubTypeName(subTypeName),
+            mAvailable(available),
+            mConnected(connected),
+            mRoaming(roaming) {}
+
+    uint32_t mType;
+    std::string mTypeName;
+    std::string mSubTypeName;
+    bool mAvailable;
+    bool mConnected;
+    bool mRoaming;
+
+    inline bool equals(SystemStatusNetworkInfo& peer) {
+        if ((mType != peer.mType) ||
+            (mTypeName != peer.mTypeName) ||
+            (mSubTypeName != peer.mSubTypeName) ||
+            (mAvailable != peer.mAvailable) ||
+            (mConnected != peer.mConnected) ||
+            (mRoaming != peer.mRoaming)) {
+            return false;
+        }
+        return true;
+    }
+    inline void dump(void) {
+        LOC_LOGD("NetworkInfo: type=%u connected=%u", mType, mConnected);
+    }
+    inline DataItemId getId() {
+        return NETWORKINFO_DATA_ITEM_ID;
+    }
+    inline void stringify(string& /*valueStr*/) { }
+    inline int32_t copy(IDataItemCore* src, bool* dataItemCopied = nullptr) {
+        SystemStatusNetworkInfo* networkinfo = static_cast<SystemStatusNetworkInfo*>(src);
+        mType = networkinfo->mType;
+        mTypeName = networkinfo->mTypeName;
+        mSubTypeName = networkinfo->mSubTypeName;
+        mAvailable = networkinfo->mAvailable;
+        mConnected = networkinfo->mConnected;
+        mRoaming = networkinfo->mRoaming;
+        if (dataItemCopied) {
+            *dataItemCopied = true;
+        }
+        return 1;
+    }
+};
+
+class SystemStatusTac : public SystemStatusItemBase, public IDataItemCore
+{
+public:
+    inline SystemStatusTac() :
+            mValue("") {}
+    inline SystemStatusTac(std::string value) :
+            mValue(value) {}
+
+    std::string mValue;
+
+    inline bool equals(SystemStatusTac& peer) {
+        return (mValue == peer.mValue);
+    }
+    inline void dump(void) {
+        LOC_LOGD("Tac: value=%s", mValue.c_str());
+    }
+    inline DataItemId getId() {
+        return TAC_DATA_ITEM_ID;
+    }
+    inline void stringify(string& /*valueStr*/) { }
+    inline int32_t copy(IDataItemCore* src, bool* dataItemCopied = nullptr) {
+        SystemStatusTac* tac = static_cast<SystemStatusTac*>(src);
+        mValue = tac->mValue;
+        if (dataItemCopied) {
+            *dataItemCopied = true;
+        }
+        return 1;
+    }
+};
+
+class SystemStatusMccMnc : public SystemStatusItemBase, public IDataItemCore
+{
+public:
+    inline SystemStatusMccMnc() :
+            mValue("") {}
+    inline SystemStatusMccMnc(std::string value) :
+            mValue(value) {}
+
+    std::string mValue;
+
+    inline bool equals(SystemStatusMccMnc& peer) {
+        return (mValue == peer.mValue);
+    }
+    inline void dump(void) {
+        LOC_LOGD("TacMccMnc value=%s", mValue.c_str());
+    }
+    inline DataItemId getId() {
+        return MCCMNC_DATA_ITEM_ID;
+    }
+    inline void stringify(string& /*valueStr*/) { }
+    inline int32_t copy(IDataItemCore* src, bool* dataItemCopied = nullptr) {
+        SystemStatusMccMnc* mccmnc = static_cast<SystemStatusMccMnc*>(src);
+        mValue = mccmnc->mValue;
+        if (dataItemCopied) {
+            *dataItemCopied = true;
+        }
+        return 1;
+    }
+};
+
+/******************************************************************************
  SystemStatusReports
 ******************************************************************************/
 class SystemStatusReports
 {
 public:
+    // from QMI_LOC indication
     std::vector<SystemStatusLocation>         mLocation;
 
+    // from ME debug NMEA
     std::vector<SystemStatusTimeAndClock>     mTimeAndClock;
     std::vector<SystemStatusXoState>          mXoState;
     std::vector<SystemStatusRfAndParams>      mRfAndParams;
     std::vector<SystemStatusErrRecovery>      mErrRecovery;
 
+    // from PE debug NMEA
     std::vector<SystemStatusInjectedPosition> mInjectedPosition;
     std::vector<SystemStatusBestPosition>     mBestPosition;
     std::vector<SystemStatusXtra>             mXtra;
@@ -388,7 +553,14 @@ public:
     std::vector<SystemStatusPdr>              mPdr;
     std::vector<SystemStatusNavData>          mNavData;
 
+    // from SM debug NMEA
     std::vector<SystemStatusPositionFailure>  mPositionFailure;
+
+    // from dataitems observer
+    std::vector<SystemStatusGpsState>         mGpsState;
+    std::vector<SystemStatusNetworkInfo>      mNetworkInfo;
+    std::vector<SystemStatusTac>              mTac;
+    std::vector<SystemStatusMccMnc>           mMccMnc;
 };
 
 /******************************************************************************
@@ -424,7 +596,13 @@ private:
 
     static const uint32_t                     maxPositionFailure = 5;
 
+    static const uint32_t                     maxGpsState = 5;
+    static const uint32_t                     maxNetworkInfo = 5;
+    static const uint32_t                     maxTac = 5;
+    static const uint32_t                     maxMccMnc = 5;
+
     SystemStatusReports mCache;
+    bool mConnected;
 
     bool setLocation(const UlpLocation& location);
 
@@ -443,6 +621,8 @@ private:
 
     bool setPositionFailure(const SystemStatusPQWS1& nmea);
 
+    bool setNetworkInfo(IDataItemCore* dataitem);
+
 public:
     // Static methods
     static SystemStatus* getInstance(const MsgTask* msgTask);
@@ -451,9 +631,11 @@ public:
 
     // Helpers
     bool eventPosition(const UlpLocation& location,const GpsLocationExtended& locationEx);
+    bool eventDataItemNotify(IDataItemCore* dataitem);
     bool setNmeaString(const char *data, uint32_t len);
     bool getReport(SystemStatusReports& reports, bool isLatestonly = false) const;
     bool setDefaultReport(void);
+    bool eventConnectionStatus(bool connected, uint8_t type);
 };
 
 } // namespace loc_core
diff --git a/core/SystemStatusOsObserver.cpp b/core/SystemStatusOsObserver.cpp
index e327f93..319f1d7 100644
--- a/core/SystemStatusOsObserver.cpp
+++ b/core/SystemStatusOsObserver.cpp
@@ -28,618 +28,565 @@
  */
 #define LOG_TAG "LocSvc_SystemStatusOsObserver"
 
-#include <string>
-#include <cinttypes>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/time.h>
-#include <pthread.h>
-#include <iterator>
 #include <algorithm>
-
-#include <MsgTask.h>
+#include <SystemStatus.h>
 #include <SystemStatusOsObserver.h>
-
-#include <DataItemId.h>
 #include <IDataItemCore.h>
 #include <IClientIndex.h>
 #include <IDataItemIndex.h>
 #include <IndexFactory.h>
-
 #include <DataItemsFactoryProxy.h>
 
-#include <platform_lib_log_util.h>
-
 namespace loc_core
 {
-#define BREAK_IF_ZERO(ERR,X) if(0==(X)) {result = (ERR); break;}
-#define BREAK_IF_NON_ZERO(ERR,X) if(0!=(X)) {result = (ERR); break;}
-
 SystemStatusOsObserver::SystemStatusOsObserver(const MsgTask* msgTask) :
-    mAddress ("SystemStatusOsObserver"),
-    mClientIndex(IndexFactory <IDataItemObserver *, DataItemId> :: createClientIndex ()),
-    mDataItemIndex(IndexFactory <IDataItemObserver *, DataItemId> :: createDataItemIndex ())
+    mAddress("SystemStatusOsObserver"),
+    mClientIndex(IndexFactory<IDataItemObserver*, DataItemId> :: createClientIndex()),
+    mDataItemIndex(IndexFactory<IDataItemObserver*, DataItemId> :: createDataItemIndex())
 {
-    int result = -1;
-    ENTRY_LOG ();
-    do {
-        BREAK_IF_ZERO (1, mClientIndex);
-        BREAK_IF_ZERO (2, mDataItemIndex);
-        mContext.mMsgTask = msgTask;
-        result = 0;
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
+    mContext.mMsgTask = msgTask;
 }
 
-SystemStatusOsObserver :: ~SystemStatusOsObserver ()
+SystemStatusOsObserver::~SystemStatusOsObserver()
 {
     // Close data-item library handle
     DataItemsFactoryProxy::closeDataItemLibraryHandle();
 
     // Destroy cache
-    map <DataItemId, IDataItemCore *> :: iterator citer = mDataItemCache.begin ();
-    for (; citer != mDataItemCache.end (); ++citer) {
-        if (citer->second != NULL) { delete citer->second; }
+    for (auto each : mDataItemCache) {
+        if (nullptr != each.second) {
+            delete each.second;
+        }
     }
-    mDataItemCache.clear ();
+
+    mDataItemCache.clear();
     delete mClientIndex;
     delete mDataItemIndex;
-    mClientIndex = NULL;
-    mDataItemIndex = NULL;
 }
 
-/******************************************************************************
- Message proc
-******************************************************************************/
-void SystemStatusOsObserver :: HandleSubscribeReq :: proc () const {
-
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mDataItemList.empty ()) {
-            LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
-            result = 0;
-            break;
-        }
-        //mDataItemList.sort ();
-        // Handle First Response
-        list <DataItemId> pendingFirstResponseList;
-        this->mParent->mClientIndex->add (this->mClient, mDataItemList, pendingFirstResponseList);
-
-        // Do not send first response for only pendingFirstResponseList,
-        // instead send for all the data items  (present in the cache) that
-        // have been subscribed for each time.
-        this->mParent->sendFirstResponse (mDataItemList, this->mClient);
-
-        list <DataItemId> yetToSubscribeDataItemsList;
-        this->mParent->mDataItemIndex->add (this->mClient, mDataItemList, yetToSubscribeDataItemsList);
-        // Send subscription list to framework
-        if (!yetToSubscribeDataItemsList.empty ()) {
-            this->mParent->mContext.mSubscriptionObj->subscribe
-            (
-                yetToSubscribeDataItemsList,
-                this->mParent
-            );
-            LOC_LOGD ("Subscribe Request sent to framework for the following data items");
-            this->mParent->logMe (yetToSubscribeDataItemsList);
-        }
+void SystemStatusOsObserver::setSubscriptionObj(IDataItemSubscription* subscriptionObj)
+{
+    mContext.mSubscriptionObj = subscriptionObj;
+
+    LOC_LOGD("Request cache size -  Subscribe:%zu RequestData:%zu",
+            mSubscribeReqCache.size(), mReqDataCache.size());
 
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
-    return;
+    // we have received the subscription object. process cached requests
+    // process - subscribe request cache
+    for (auto each : mSubscribeReqCache) {
+        subscribe(each.second, each.first);
+    }
+    // process - requestData request cache
+    for (auto each : mReqDataCache) {
+        requestData(each.second, each.first);
+    }
 }
 
-void SystemStatusOsObserver :: HandleUpdateSubscriptionReq :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mDataItemList.empty ()) {
-            LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
-            result = 0;
-            break;
-        }
-        //mDataItemList.sort ();
-        list <DataItemId> currentlySubscribedList;
-        this->mParent->mClientIndex->getSubscribedList (this->mClient, currentlySubscribedList);
-        list <DataItemId> removeDataItemList;
-        set_difference (currentlySubscribedList.begin (), currentlySubscribedList.end (),
-                       mDataItemList.begin (), mDataItemList.end (),
-                       inserter (removeDataItemList,removeDataItemList.begin ()));
-        // Handle First Response
-        list <DataItemId> pendingFirstResponseList;
-        this->mParent->mClientIndex->add (this->mClient, mDataItemList, pendingFirstResponseList);
-        // Send First Response
-        this->mParent->sendFirstResponse (pendingFirstResponseList, this->mClient);
-
-        list <DataItemId> yetToSubscribeDataItemsList;
-        this->mParent->mDataItemIndex->add (this->mClient, mDataItemList, yetToSubscribeDataItemsList);
-        // Send subscription list to framework
-        if (!yetToSubscribeDataItemsList.empty ()) {
-            this->mParent->mContext.mSubscriptionObj->subscribe
-            (
-                yetToSubscribeDataItemsList,
-                this->mParent
-            );
-            LOC_LOGD ("Subscribe Request sent to framework for the following data items");
-            this->mParent->logMe (yetToSubscribeDataItemsList);
+// Helper to cache requests subscribe and requestData till subscription obj is obtained
+void SystemStatusOsObserver::cacheObserverRequest(ObserverReqCache& reqCache,
+        const list<DataItemId>& l, IDataItemObserver* client)
+{
+    ObserverReqCache::iterator dicIter = reqCache.find(client);
+    if (dicIter != reqCache.end()) {
+        // found
+        list<DataItemId> difference(0);
+        set_difference(l.begin(), l.end(),
+                dicIter->second.begin(), dicIter->second.end(),
+                inserter(difference, difference.begin()));
+        if (!difference.empty()) {
+            difference.sort();
+            dicIter->second.merge(difference);
+            dicIter->second.unique();
         }
+    }
+    else {
+        // not found
+        reqCache[client] = l;
+    }
+}
 
-        list <DataItemId> unsubscribeList;
-        list <DataItemId> unused;
-        this->mParent->mClientIndex->remove (this->mClient, removeDataItemList, unused);
+/******************************************************************************
+ IDataItemSubscription Overrides
+******************************************************************************/
+void SystemStatusOsObserver::subscribe(
+        const list<DataItemId>& l, IDataItemObserver* client)
+{
+    if (nullptr == mContext.mSubscriptionObj) {
+        LOC_LOGD("%s]: Subscription object is NULL. Caching requests", __func__);
+        cacheObserverRequest(mSubscribeReqCache, l, client);
+        return;
+    }
 
-        if (!this->mParent->mClientIndex->isSubscribedClient (this->mClient)) {
-            this->mParent->mDataItemIndex->remove (list <IDataItemObserver *> (1,this->mClient), unsubscribeList);
-        }
-        if (!unsubscribeList.empty ()) {
-            // Send unsubscribe to framework
-            this->mParent->mContext.mSubscriptionObj->unsubscribe
-            (
-                unsubscribeList,
-                this->mParent
-            );
-            LOC_LOGD ("Unsubscribe Request sent to framework for the following data items");
-            this->mParent->logMe (unsubscribeList);
-        }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
-}
+    struct HandleSubscribeReq : public LocMsg {
+        HandleSubscribeReq(SystemStatusOsObserver* parent,
+                const list<DataItemId>& l, IDataItemObserver* client) :
+                mParent(parent), mClient(client), mDataItemList(l) {}
+        virtual ~HandleSubscribeReq() {}
+        void proc() const {
 
-void SystemStatusOsObserver :: HandleRequestData :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
+            if (mDataItemList.empty()) {
+                LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
+                return;
+            }
 
-    do {
-        if (mDataItemList.empty ()) {
-            LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
-            result = 0;
-            break;
-        }
-        //mDataItemList.sort ();
-        list <DataItemId> yetToSubscribeDataItemsList;
-        this->mParent->mClientIndex->add (this->mClient, mDataItemList, yetToSubscribeDataItemsList);
-        this->mParent->mDataItemIndex->add (this->mClient, mDataItemList, yetToSubscribeDataItemsList);
-        // Send subscription list to framework
-        if (!mDataItemList.empty ()) {
-            this->mParent->mContext.mSubscriptionObj->requestData
-            (
-                mDataItemList,
-                this->mParent
-            );
-            LOC_LOGD ("Subscribe Request sent to framework for the following data items");
-            this->mParent->logMe (yetToSubscribeDataItemsList);
-        }
+            // Handle First Response
+            list<DataItemId> pendingFirstResponseList(0);
+            mParent->mClientIndex->add(mClient, mDataItemList, pendingFirstResponseList);
 
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
-}
+            // Do not send first response for only pendingFirstResponseList,
+            // instead send for all the data items  (present in the cache) that
+            // have been subscribed for each time.
+            mParent->sendFirstResponse(mDataItemList, mClient);
 
-void SystemStatusOsObserver :: HandleUnsubscribeReq :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mDataItemList.empty ()) {
-            LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
-            result = 0;
-            break;
-        }
-        //mDataItemList.sort ();
-        list <DataItemId> unsubscribeList;
-        list <DataItemId> unused;
-        this->mParent->mClientIndex->remove (this->mClient, mDataItemList, unused);
-
-        list <DataItemId> :: const_iterator it = mDataItemList.begin ();
-        for (; it != mDataItemList.end (); ++it) {
-            list <IDataItemObserver *> clientListSubs;
-            list <IDataItemObserver *> clientListOut;
-            this->mParent->mDataItemIndex->remove ((*it),
-                                list <IDataItemObserver *> (1,this->mClient), clientListOut);
-            // check if there are any other subscribed client for this data item id
-            this->mParent->mDataItemIndex->getListOfSubscribedClients ( (*it), clientListSubs);
-            if (clientListSubs.empty())
-            {
-                LOC_LOGD ("Client list subscribed is empty for dataitem - %d",(*it));
-                unsubscribeList.push_back((*it));
-            }
-        }
-        if (!unsubscribeList.empty ()) {
-            // Send unsubscribe to framework
-            this->mParent->mContext.mSubscriptionObj->unsubscribe
-            (
-                unsubscribeList,
-                this->mParent
-            );
-            LOC_LOGD ("Unsubscribe Request sent to framework for the following data items");
-            this->mParent->logMe (unsubscribeList);
-        }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
-}
+            list<DataItemId> yetToSubscribeDataItemsList(0);
+            mParent->mDataItemIndex->add(mClient, mDataItemList, yetToSubscribeDataItemsList);
 
-void SystemStatusOsObserver :: HandleUnsubscribeAllReq :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        list <IDataItemObserver *> clients (1, this->mClient);
-        list <DataItemId> unsubscribeList;
-        BREAK_IF_NON_ZERO (2, this->mParent->mClientIndex->remove (this->mClient));
-
-
-        this->mParent->mDataItemIndex->remove (clients, unsubscribeList);
-        if (!unsubscribeList.empty ()) {
-            // Send unsubscribe to framework
-            this->mParent->mContext.mSubscriptionObj->unsubscribe
-            (
-                unsubscribeList,
-                this->mParent
-            );
-            LOC_LOGD ("Unsubscribe Request sent to framework for the following data items");
-            this->mParent->logMe (unsubscribeList);
+            // Send subscription list to framework
+            if (!yetToSubscribeDataItemsList.empty()) {
+                mParent->mContext.mSubscriptionObj->subscribe(yetToSubscribeDataItemsList, mParent);
+                LOC_LOGD("Subscribe Request sent to framework for the following");
+                mParent->logMe(yetToSubscribeDataItemsList);
+            }
         }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
+        SystemStatusOsObserver* mParent;
+        IDataItemObserver* mClient;
+        const list<DataItemId> mDataItemList;
+    };
+    mContext.mMsgTask->sendMsg(new (nothrow) HandleSubscribeReq(this, l, client));
 }
 
-void SystemStatusOsObserver :: HandleNotify :: getListOfClients
- (const list <DataItemId> & dlist, list <IDataItemObserver *> & clients ) const {
-
-     list <DataItemId> :: const_iterator it = dlist.begin ();
-     for (; it != dlist.end (); ++it) {
-         list <IDataItemObserver *> clientList;
-         this->mParent->mDataItemIndex->getListOfSubscribedClients ( (*it), clientList);
-         list <IDataItemObserver *> :: iterator citer = clientList.begin ();
-         for (; citer != clientList.end (); ++citer) {
-             clients.push_back (*citer);
-         }
-         clientList.clear ();
-     }
-     // remove duplicates
-     clients.unique ();
-}
+void SystemStatusOsObserver::updateSubscription(
+        const list<DataItemId>& l, IDataItemObserver* client)
+{
+    if (nullptr == mContext.mSubscriptionObj) {
+        LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
+        return;
+    }
 
-void SystemStatusOsObserver :: HandleNotify :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        // Update Cache with received data items and prepare
-        // list of data items to be sent.
-        list <IDataItemCore *> :: const_iterator it = mDList.begin ();
-        list <DataItemId> dataItemIdsToBeSent;
-        for (; it != mDList.end (); ++it) {
-            bool dataItemUpdated = false;
-            this->mParent->updateCache (*it, dataItemUpdated);
-            if (dataItemUpdated) {
-                dataItemIdsToBeSent.push_back ( (*it)->getId ());
+    struct HandleUpdateSubscriptionReq : public LocMsg {
+        HandleUpdateSubscriptionReq(SystemStatusOsObserver* parent,
+                const list<DataItemId>& l, IDataItemObserver* client) :
+                mParent(parent), mClient(client), mDataItemList(l) {}
+        virtual ~HandleUpdateSubscriptionReq() {}
+        void proc() const {
+            if (mDataItemList.empty()) {
+                LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
+                return;
             }
-        }
 
-        list <IDataItemObserver *> clientList;
-        this->getListOfClients (dataItemIdsToBeSent, clientList);
-        list <IDataItemObserver *> :: iterator citer = clientList.begin ();
-        // Send data item to all subscribed clients
-        LOC_LOGD ("LocTech-Label :: SystemStatusOsObserver :: Data Items Out");
-        for (; citer != clientList.end (); ++citer) {
-            do {
-                list <DataItemId> dataItemIdsSubscribedByThisClient;
-                list <DataItemId> dataItemIdsToBeSentForThisClient;
-                this->mParent->mClientIndex->getSubscribedList (*citer, dataItemIdsSubscribedByThisClient);
-                dataItemIdsSubscribedByThisClient.sort ();
-                dataItemIdsToBeSent.sort ();
-                set_intersection (dataItemIdsToBeSent.begin (),
-                                 dataItemIdsToBeSent.end (),
-                                 dataItemIdsSubscribedByThisClient.begin (),
-                                 dataItemIdsSubscribedByThisClient.end (),
-                                 inserter (dataItemIdsToBeSentForThisClient,
-                                         dataItemIdsToBeSentForThisClient.begin ()));
-                BREAK_IF_NON_ZERO (4,this->mParent->sendCachedDataItems (dataItemIdsToBeSentForThisClient, *citer));
-                dataItemIdsSubscribedByThisClient.clear ();
-                dataItemIdsToBeSentForThisClient.clear ();
-            } while (0);
-        }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
-}
+            list<DataItemId> currentlySubscribedList(0);
+            mParent->mClientIndex->getSubscribedList(mClient, currentlySubscribedList);
 
-void SystemStatusOsObserver :: HandleTurnOn :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        // Send action turn on to framework
-        this->mParent->mContext.mFrameworkActionReqObj->turnOn(mDataItemId, mTimeOut);
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
-}
+            list<DataItemId> removeDataItemList(0);
+            set_difference(currentlySubscribedList.begin(), currentlySubscribedList.end(),
+                    mDataItemList.begin(), mDataItemList.end(),
+                    inserter(removeDataItemList,removeDataItemList.begin()));
 
-void SystemStatusOsObserver :: HandleTurnOff :: proc () const {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        // Send action turn off to framework
-        this->mParent->mContext.mFrameworkActionReqObj->turnOff(mDataItemId);
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
-}
+            // Handle First Response
+            list<DataItemId> pendingFirstResponseList(0);
+            mParent->mClientIndex->add(mClient, mDataItemList, pendingFirstResponseList);
 
-/******************************************************************************
- IDataItemSubscription Overrides
-******************************************************************************/
-void SystemStatusOsObserver :: subscribe (const list <DataItemId> & l, IDataItemObserver * client) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mSubscriptionObj != NULL) {
-            HandleSubscribeReq * msg = new  (nothrow) HandleSubscribeReq (this, l, client);
-            mContext.mMsgTask->sendMsg (msg);
-        }
-        else {
-            LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
-            result = 1;
-        }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
-}
+            // Send First Response
+            mParent->sendFirstResponse(pendingFirstResponseList, mClient);
 
-void SystemStatusOsObserver :: updateSubscription (const list <DataItemId> & l, IDataItemObserver * client) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mSubscriptionObj != NULL) {
-            mContext.mMsgTask->sendMsg (new  (nothrow) HandleUpdateSubscriptionReq (this, l, client));
-        }
-        else {
-            LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
-            result = 1;
+            list<DataItemId> yetToSubscribeDataItemsList(0);
+            mParent->mDataItemIndex->add(
+                    mClient, mDataItemList, yetToSubscribeDataItemsList);
+
+            // Send subscription list to framework
+            if (!yetToSubscribeDataItemsList.empty()) {
+                mParent->mContext.mSubscriptionObj->subscribe(
+                        yetToSubscribeDataItemsList, mParent);
+                LOC_LOGD("Subscribe Request sent to framework for the following");
+                mParent->logMe(yetToSubscribeDataItemsList);
+            }
+
+            list<DataItemId> unsubscribeList(0);
+            list<DataItemId> unused(0);
+            mParent->mClientIndex->remove(mClient, removeDataItemList, unused);
+
+            if (!mParent->mClientIndex->isSubscribedClient(mClient)) {
+                mParent->mDataItemIndex->remove(
+                        list<IDataItemObserver*> (1,mClient), unsubscribeList);
+            }
+            if (!unsubscribeList.empty()) {
+                // Send unsubscribe to framework
+                mParent->mContext.mSubscriptionObj->unsubscribe(unsubscribeList, mParent);
+                LOC_LOGD("Unsubscribe Request sent to framework for the following");
+                mParent->logMe(unsubscribeList);
+            }
         }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
+        SystemStatusOsObserver* mParent;
+        IDataItemObserver* mClient;
+        const list<DataItemId> mDataItemList;
+    };
+    mContext.mMsgTask->sendMsg(new (nothrow) HandleUpdateSubscriptionReq(this, l, client));
 }
 
-void SystemStatusOsObserver :: requestData (const list <DataItemId> & l, IDataItemObserver * client) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mSubscriptionObj != NULL) {
-            mContext.mMsgTask->sendMsg (new  (nothrow) HandleRequestData (this, l, client));
-        }
-        else {
-            LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
-            result = 1;
-        }
-    } while (0);
+void SystemStatusOsObserver::requestData(
+        const list<DataItemId>& l, IDataItemObserver* client)
+{
+    if (nullptr == mContext.mSubscriptionObj) {
+        LOC_LOGD("%s]: Subscription object is NULL. Caching requests", __func__);
+        cacheObserverRequest(mReqDataCache, l, client);
+        return;
+    }
 
-    EXIT_LOG_WITH_ERROR ("%d",result);
-}
+    struct HandleRequestData : public LocMsg {
+        HandleRequestData(SystemStatusOsObserver* parent,
+                const list<DataItemId>& l, IDataItemObserver* client) :
+                mParent(parent), mClient(client), mDataItemList(l) {}
+        virtual ~HandleRequestData() {}
+        void proc() const {
+            if (mDataItemList.empty()) {
+                LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
+                return;
+            }
 
-void SystemStatusOsObserver :: unsubscribe (const list <DataItemId> & l, IDataItemObserver * client) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mSubscriptionObj != NULL) {
-            mContext.mMsgTask->sendMsg (new  (nothrow) HandleUnsubscribeReq (this, l, client));
-        }
-        else {
-            LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
-            result = 1;
+            list<DataItemId> yetToSubscribeDataItemsList(0);
+            mParent->mClientIndex->add(
+                    mClient, mDataItemList, yetToSubscribeDataItemsList);
+            mParent->mDataItemIndex->add(
+                    mClient, mDataItemList, yetToSubscribeDataItemsList);
+
+            // Send subscription list to framework
+            if (!mDataItemList.empty()) {
+                mParent->mContext.mSubscriptionObj->requestData(mDataItemList, mParent);
+                LOC_LOGD("Subscribe Request sent to framework for the following");
+                mParent->logMe(yetToSubscribeDataItemsList);
+            }
         }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
+        SystemStatusOsObserver* mParent;
+        IDataItemObserver* mClient;
+        const list<DataItemId> mDataItemList;
+    };
+    mContext.mMsgTask->sendMsg(new (nothrow) HandleRequestData(this, l, client));
 }
 
-void SystemStatusOsObserver :: unsubscribeAll (IDataItemObserver * client) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mSubscriptionObj != NULL) {
-            mContext.mMsgTask->sendMsg (new  (nothrow) HandleUnsubscribeAllReq (this, client));
-        }
-        else {
-            LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
-            result = 1;
+void SystemStatusOsObserver::unsubscribe(
+        const list<DataItemId>& l, IDataItemObserver* client)
+{
+    if (nullptr == mContext.mSubscriptionObj) {
+        LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
+        return;
+    }
+    struct HandleUnsubscribeReq : public LocMsg {
+        HandleUnsubscribeReq(SystemStatusOsObserver* parent,
+                const list<DataItemId>& l, IDataItemObserver* client) :
+                mParent(parent), mClient(client), mDataItemList(l) {}
+        virtual ~HandleUnsubscribeReq() {}
+        void proc() const {
+            if (mDataItemList.empty()) {
+                LOC_LOGV("mDataItemList is empty. Nothing to do. Exiting");
+                return;
+            }
+
+            list<DataItemId> unsubscribeList(0);
+            list<DataItemId> unused(0);
+            mParent->mClientIndex->remove(mClient, mDataItemList, unused);
+
+            for (auto each : mDataItemList) {
+                list<IDataItemObserver*> clientListSubs(0);
+                list<IDataItemObserver*> clientListOut(0);
+                mParent->mDataItemIndex->remove(
+                        each, list<IDataItemObserver*> (1,mClient), clientListOut);
+                // check if there are any other subscribed client for this data item id
+                mParent->mDataItemIndex->getListOfSubscribedClients(each, clientListSubs);
+                if (clientListSubs.empty())
+                {
+                    LOC_LOGD("Client list subscribed is empty for dataitem - %d", each);
+                    unsubscribeList.push_back(each);
+                }
+            }
+
+            if (!unsubscribeList.empty()) {
+                // Send unsubscribe to framework
+                mParent->mContext.mSubscriptionObj->unsubscribe(unsubscribeList, mParent);
+                LOC_LOGD("Unsubscribe Request sent to framework for the following data items");
+                mParent->logMe(unsubscribeList);
+            }
         }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d",result);
+        SystemStatusOsObserver* mParent;
+        IDataItemObserver* mClient;
+        const list<DataItemId> mDataItemList;
+    };
+    mContext.mMsgTask->sendMsg(new (nothrow) HandleUnsubscribeReq(this, l, client));
 }
 
-/******************************************************************************
- IDataItemObserver Overrides
-******************************************************************************/
-void SystemStatusOsObserver::getName(string & name) {
-    name = mAddress;
-}
+void SystemStatusOsObserver::unsubscribeAll(IDataItemObserver* client)
+{
+    if (nullptr == mContext.mSubscriptionObj) {
+        LOC_LOGE("%s:%d]: Subscription object is NULL", __func__, __LINE__);
+        return;
+    }
+
+    struct HandleUnsubscribeAllReq : public LocMsg {
+        HandleUnsubscribeAllReq(SystemStatusOsObserver* parent,
+                IDataItemObserver* client) :
+                mParent(parent), mClient(client) {}
+        virtual ~HandleUnsubscribeAllReq() {}
+        void proc() const {
+            list<IDataItemObserver*> clients(1, mClient);
+            list<DataItemId> unsubscribeList(0);
+            if(0 == mParent->mClientIndex->remove(mClient)) {
+                return;
+            }
+            mParent->mDataItemIndex->remove(clients, unsubscribeList);
 
-void SystemStatusOsObserver::notify(const std::list <IDataItemCore *> & dlist) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        list <IDataItemCore *> :: const_iterator it = dlist.begin ();
-        list <IDataItemCore *> dataItemList;
-        list <DataItemId> ids;
-        LOC_LOGD("LocTech-Label :: SystemStatusOsObserver :: Data Items In");
-        for (; it != dlist.end (); ++it) {
-            if (*it != NULL) {
-                string dv;
-                (*it)->stringify(dv);
-                LOC_LOGD("LocTech-Value :: Data Item Value: %s", dv.c_str ());
-                IDataItemCore * dataitem = DataItemsFactoryProxy::createNewDataItem((*it)->getId());
-                BREAK_IF_ZERO (2, dataitem);
-                // Copy contents into the newly created data item
-                dataitem->copy(*it);
-                dataItemList.push_back(dataitem);
-                ids.push_back((*it)->getId());
+            if (!unsubscribeList.empty()) {
+                // Send unsubscribe to framework
+                mParent->mContext.mSubscriptionObj->unsubscribe(unsubscribeList, mParent);
+                LOC_LOGD("Unsubscribe Request sent to framework for the following data items");
+                mParent->logMe(unsubscribeList);
             }
         }
-        mContext.mMsgTask->sendMsg(new (nothrow) HandleNotify (this, dataItemList));
-    } while  (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
+        SystemStatusOsObserver* mParent;
+        IDataItemObserver* mClient;
+    };
+    mContext.mMsgTask->sendMsg(new (nothrow) HandleUnsubscribeAllReq(this, client));
 }
 
 /******************************************************************************
- IFrameworkActionReq Overrides
+ IDataItemObserver Overrides
 ******************************************************************************/
-void SystemStatusOsObserver :: turnOn (DataItemId dit, int timeOut) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mFrameworkActionReqObj != NULL) {
-            // Check if data item exists in mActiveRequestCount
-            map <DataItemId, int> :: iterator citer = mActiveRequestCount.find (dit);
-            if (citer == mActiveRequestCount.end ()) {
-                // Data item not found in map
-                // Add reference count as 1 and add dataitem to map
-                pair <DataItemId, int> cpair (dit, 1);
-                mActiveRequestCount.insert (cpair);
-                LOC_LOGD("Sending turnOn request");
-                // Send action turn on to framework
-                mContext.mMsgTask->sendMsg (new  (nothrow) HandleTurnOn (this, dit, timeOut));
-            } else {
-                // Found in map, update reference count
-                citer->second++;
-                LOC_LOGD("HandleTurnOn - Data item:%d Num_refs:%d",dit,citer->second);
-            }
+void SystemStatusOsObserver::notify(const list<IDataItemCore*>& dlist)
+{
+    list<IDataItemCore*> dataItemList(0);
+
+    for (auto each : dlist) {
+        string dv;
+        each->stringify(dv);
+        LOC_LOGD("notify: DataItem In Value:%s", dv.c_str());
+
+        IDataItemCore* di = DataItemsFactoryProxy::createNewDataItem(each->getId());
+        if (nullptr == di) {
+            LOC_LOGE("Unable to create dataitem:%d", each->getId());
+            return;
         }
-        else {
-            LOC_LOGE("%s:%d]: Framework action request object is NULL", __func__, __LINE__);
-            result = 1;
+
+        // Copy contents into the newly created data item
+        di->copy(each);
+        dataItemList.push_back(di);
+        // Request systemstatus to record this dataitem in its cache
+        SystemStatus* systemstatus = SystemStatus::getInstance(mContext.mMsgTask);
+        if(nullptr != systemstatus) {
+            systemstatus->eventDataItemNotify(di);
         }
-    } while (0);
+    }
 
-    EXIT_LOG_WITH_ERROR ("%d", result);
-}
+    struct HandleNotify : public LocMsg {
+        HandleNotify(SystemStatusOsObserver* parent, const list<IDataItemCore*>& l) :
+            mParent(parent), mDList(l) {}
+        virtual ~HandleNotify() {
+            for (auto each : mDList) {
+                delete each;
+            }
+        }
+        void proc() const {
+            // Update Cache with received data items and prepare
+            // list of data items to be sent.
+            list<DataItemId> dataItemIdsToBeSent(0);
+            for (auto item : mDList) {
+                bool dataItemUpdated = false;
+                mParent->updateCache(item, dataItemUpdated);
+                if (dataItemUpdated) {
+                    dataItemIdsToBeSent.push_back(item->getId());
+                }
+            }
 
-void SystemStatusOsObserver :: turnOff (DataItemId dit) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (mContext.mFrameworkActionReqObj != NULL) {
-            // Check if data item exists in mActiveRequestCount
-            map <DataItemId, int> :: iterator citer = mActiveRequestCount.find (dit);
-            if (citer != mActiveRequestCount.end ()) {
-                citer->second--;
-                LOC_LOGD("HandleTurnOff - Data item:%d Remaining Num_refs:%d",dit,citer->second);
-
-                if(citer->second == 0) {
-                    LOC_LOGD("Sending turnOff request");
-                    // if this was last reference, remove item from map and turn off module
-                    mActiveRequestCount.erase(citer);
-                    // Send action turn off to framework
-                    mContext.mMsgTask->sendMsg (new  (nothrow) HandleTurnOff (this, dit));
+            // Send data item to all subscribed clients
+            list<IDataItemObserver*> clientList(0);
+            for (auto each : dataItemIdsToBeSent) {
+                list<IDataItemObserver*> clients(0);
+                mParent->mDataItemIndex->getListOfSubscribedClients(each, clients);
+                for (auto each_cient: clients) {
+                    clientList.push_back(each_cient);
                 }
-            } else {
-                // Not found in map
-                LOC_LOGD ("Data item id %d not found in FrameworkModuleMap",dit);
+            }
+            clientList.unique();
+
+            for (auto client : clientList) {
+                list<DataItemId> dataItemIdsSubscribedByThisClient(0);
+                list<DataItemId> dataItemIdsToBeSentForThisClient(0);
+                mParent->mClientIndex->getSubscribedList(
+                        client, dataItemIdsSubscribedByThisClient);
+                dataItemIdsSubscribedByThisClient.sort();
+                dataItemIdsToBeSent.sort();
+
+                set_intersection(dataItemIdsToBeSent.begin(),
+                        dataItemIdsToBeSent.end(),
+                        dataItemIdsSubscribedByThisClient.begin(),
+                        dataItemIdsSubscribedByThisClient.end(),
+                        inserter(dataItemIdsToBeSentForThisClient,
+                        dataItemIdsToBeSentForThisClient.begin()));
+
+                mParent->sendCachedDataItems(dataItemIdsToBeSentForThisClient, client);
+                dataItemIdsSubscribedByThisClient.clear();
+                dataItemIdsToBeSentForThisClient.clear();
             }
         }
-        else {
-            LOC_LOGE("%s:%d]: Framework action request object is NULL", __func__, __LINE__);
-            result = 1;
-        }
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
+        SystemStatusOsObserver* mParent;
+        const list<IDataItemCore*> mDList;
+    };
+    mContext.mMsgTask->sendMsg(new (nothrow) HandleNotify(this, dataItemList));
 }
 
 /******************************************************************************
- Helpers
+ IFrameworkActionReq Overrides
 ******************************************************************************/
-void SystemStatusOsObserver :: logMe (const list <DataItemId> & l) {
-    list <DataItemId> :: const_iterator it = l.begin ();
-    for (;it != l.end (); ++it) {
-        LOC_LOGD ("DataItem %d",*it);
+void SystemStatusOsObserver::turnOn(DataItemId dit, int timeOut)
+{
+    if (nullptr == mContext.mFrameworkActionReqObj) {
+        LOC_LOGE("%s:%d]: Framework action request object is NULL", __func__, __LINE__);
+        return;
     }
-}
 
-int SystemStatusOsObserver :: sendFirstResponse (const list <DataItemId> & l, IDataItemObserver * to) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        if (l.empty ()) {
-            LOC_LOGV("list is empty. Nothing to do. Exiting");
-            result = 0;
-            break;
-        }
+    // Check if data item exists in mActiveRequestCount
+    map<DataItemId, int>::iterator citer = mActiveRequestCount.find(dit);
+    if (citer == mActiveRequestCount.end()) {
+        // Data item not found in map
+        // Add reference count as 1 and add dataitem to map
+        pair<DataItemId, int> cpair(dit, 1);
+        mActiveRequestCount.insert(cpair);
+        LOC_LOGD("Sending turnOn request");
 
-        string clientName;
-        to->getName (clientName);
-        LOC_LOGD ("First response sent for the following data items To Client: %s", clientName.c_str());
-
-        list <IDataItemCore *> dataItems;
-        list <DataItemId> :: const_iterator diditer = l.begin ();
-        for (; diditer != l.end (); ++diditer) {
-            map <DataItemId, IDataItemCore*> :: const_iterator citer = mDataItemCache.find (*diditer);
-            if (citer != mDataItemCache.end ()) {
-                string dv;
-                IDataItemCore * di = citer->second;
-                di->stringify (dv);
-                LOC_LOGD ("LocTech-Value :: Data Item: %s", dv.c_str ());
-                dataItems.push_back (citer->second);
+        // Send action turn on to framework
+        struct HandleTurnOnMsg : public LocMsg {
+            HandleTurnOnMsg(IFrameworkActionReq* framework,
+                    DataItemId dit, int timeOut) :
+                    mFrameworkActionReqObj(framework), mDataItemId(dit), mTimeOut(timeOut) {}
+            virtual ~HandleTurnOnMsg() {}
+            void proc() const {
+                mFrameworkActionReqObj->turnOn(mDataItemId, mTimeOut);
             }
-        }
-        if (dataItems.empty ()) {
-            LOC_LOGV("No items to notify. Nothing to do. Exiting");
-            result = 0;
-            break;
-        }
+            IFrameworkActionReq* mFrameworkActionReqObj;
+            DataItemId mDataItemId;
+            int mTimeOut;
+        };
+        mContext.mMsgTask->sendMsg(new (nothrow) HandleTurnOnMsg(this, dit, timeOut));
+    }
+    else {
+        // Found in map, update reference count
+        citer->second++;
+        LOC_LOGD("turnOn - Data item:%d Num_refs:%d", dit, citer->second);
+    }
+}
 
-        // Notify Client
-        to->notify (dataItems);
+void SystemStatusOsObserver::turnOff(DataItemId dit)
+{
+    if (nullptr == mContext.mFrameworkActionReqObj) {
+        LOC_LOGE("%s:%d]: Framework action request object is NULL", __func__, __LINE__);
+        return;
+    }
 
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
-    return result;
+    // Check if data item exists in mActiveRequestCount
+    map<DataItemId, int>::iterator citer = mActiveRequestCount.find(dit);
+    if (citer != mActiveRequestCount.end()) {
+        // found
+        citer->second--;
+        LOC_LOGD("turnOff - Data item:%d Remaining:%d", dit, citer->second);
+        if(citer->second == 0) {
+            // if this was last reference, remove item from map and turn off module
+            mActiveRequestCount.erase(citer);
+
+            // Send action turn off to framework
+            struct HandleTurnOffMsg : public LocMsg {
+                HandleTurnOffMsg(IFrameworkActionReq* framework, DataItemId dit) :
+                    mFrameworkActionReqObj(framework), mDataItemId(dit) {}
+                virtual ~HandleTurnOffMsg() {}
+                void proc() const {
+                    mFrameworkActionReqObj->turnOff(mDataItemId);
+                }
+                IFrameworkActionReq* mFrameworkActionReqObj;
+                DataItemId mDataItemId;
+            };
+            mContext.mMsgTask->sendMsg(
+                    new (nothrow) HandleTurnOffMsg(mContext.mFrameworkActionReqObj, dit));
+        }
+    }
 }
 
-int SystemStatusOsObserver :: sendCachedDataItems (const list <DataItemId> & l, IDataItemObserver * to) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        list <IDataItemCore *> dataItems;
-        list <DataItemId> :: const_iterator it = l.begin ();
-        string clientName;
-        to->getName (clientName);
-        LOC_LOGD ("LocTech-Value :: To Client: %s", clientName.c_str ());
-        for (; it != l.end (); ++it) {
+/******************************************************************************
+ Helpers
+******************************************************************************/
+void SystemStatusOsObserver::sendFirstResponse(
+        const list<DataItemId>& l, IDataItemObserver* to)
+{
+    if (l.empty()) {
+        LOC_LOGV("list is empty. Nothing to do. Exiting");
+        return;
+    }
+
+    string clientName;
+    to->getName(clientName);
+    list<IDataItemCore*> dataItems(0);
+
+    for (auto each : l) {
+        map<DataItemId, IDataItemCore*>::const_iterator citer = mDataItemCache.find(each);
+        if (citer != mDataItemCache.end()) {
             string dv;
-            IDataItemCore * di = this->mDataItemCache [ (*it) ];
-            di->stringify (dv);
-            LOC_LOGI("LocTech-Value :: Data Item: %s >> %s", dv.c_str(), clientName.c_str());
-            dataItems.push_back (di);
+            citer->second->stringify(dv);
+            LOC_LOGI("DataItem: %s >> %s", dv.c_str(), clientName.c_str());
+            dataItems.push_back(citer->second);
         }
+    }
+    if (dataItems.empty()) {
+        LOC_LOGV("No items to notify. Nothing to do. Exiting");
+        return;
+    }
+    to->notify(dataItems);
+}
 
-        to->notify (dataItems);
-
-    } while (0);
-    EXIT_LOG_WITH_ERROR ("%d", result);
-    return result;
+void SystemStatusOsObserver::sendCachedDataItems(
+        const list<DataItemId>& l, IDataItemObserver* to)
+{
+    string clientName;
+    to->getName(clientName);
+    list<IDataItemCore*> dataItems(0);
+
+    for (auto each : l) {
+        string dv;
+        IDataItemCore* di = mDataItemCache[each];
+        di->stringify(dv);
+        LOC_LOGI("DataItem: %s >> %s", dv.c_str(), clientName.c_str());
+        dataItems.push_back(di);
+    }
+    to->notify(dataItems);
 }
 
-int SystemStatusOsObserver :: updateCache (IDataItemCore * d, bool &dataItemUpdated) {
-    int result = 0;
-    ENTRY_LOG ();
-    do {
-        BREAK_IF_ZERO (1, d);
-        // Check if data item exists in cache
-        map <DataItemId, IDataItemCore*> :: iterator citer = mDataItemCache.find (d->getId ());
-        if (citer == mDataItemCache.end ()) {
-            // New data item; not found in cache
-            IDataItemCore * dataitem = DataItemsFactoryProxy::createNewDataItem(d->getId());
-            BREAK_IF_ZERO (2, dataitem);
-            // Copy the contents of the data item
-            dataitem->copy (d);
-            pair <DataItemId, IDataItemCore*> cpair (d->getId (), dataitem);
-            // Insert in mDataItemCache
-            mDataItemCache.insert (cpair);
-            dataItemUpdated = true;
-        } else {
-            // Found in cache; Update cache if necessary
-            BREAK_IF_NON_ZERO(3, citer->second->copy (d, &dataItemUpdated));
-        }
+void SystemStatusOsObserver::updateCache(IDataItemCore* d, bool& dataItemUpdated)
+{
+    if (nullptr == d) {
+        return;
+    }
 
-        if (dataItemUpdated) {
-            LOC_LOGV("DataItem:%d updated:%d", d->getId (), dataItemUpdated);
+    // Check if data item exists in cache
+    map<DataItemId, IDataItemCore*>::iterator citer =
+            mDataItemCache.find(d->getId());
+    if (citer == mDataItemCache.end()) {
+        // New data item; not found in cache
+        IDataItemCore* dataitem = DataItemsFactoryProxy::createNewDataItem(d->getId());
+        if (nullptr == dataitem) {
+            return;
+        }
+
+        // Copy the contents of the data item
+        dataitem->copy(d);
+        pair<DataItemId, IDataItemCore*> cpair(d->getId(), dataitem);
+        // Insert in mDataItemCache
+        mDataItemCache.insert(cpair);
+        dataItemUpdated = true;
+    }
+    else {
+        // Found in cache; Update cache if necessary
+        if(0 == citer->second->copy(d, &dataItemUpdated)) {
+            return;
         }
-    } while (0);
+    }
 
-    EXIT_LOG_WITH_ERROR ("%d", result);
-    return result;
+    if (dataItemUpdated) {
+        LOC_LOGV("DataItem:%d updated:%d", d->getId(), dataItemUpdated);
+    }
 }
 
 } // namespace loc_core
diff --git a/core/SystemStatusOsObserver.h b/core/SystemStatusOsObserver.h
index 8e42d21..985e5c9 100644
--- a/core/SystemStatusOsObserver.h
+++ b/core/SystemStatusOsObserver.h
@@ -29,36 +29,34 @@
 #ifndef __SYSTEM_STATUS_OSOBSERVER__
 #define __SYSTEM_STATUS_OSOBSERVER__
 
-#include <stdint.h>
+#include <cinttypes>
 #include <string>
 #include <list>
 #include <map>
 #include <new>
 #include <vector>
-#include <platform_lib_log_util.h>
-#include <DataItemId.h>
+
 #include <MsgTask.h>
+#include <DataItemId.h>
 #include <IOsObserver.h>
+#include <platform_lib_log_util.h>
 
 namespace loc_core
 {
-
 /******************************************************************************
  SystemStatusOsObserver
 ******************************************************************************/
+using namespace std;
+
 // Forward Declarations
 class IDataItemCore;
-
-template <typename CT, typename DIT>
-class IClientIndex;
-
-template <typename CT, typename DIT>
-class IDataItemIndex;
+template<typename CT, typename DIT> class IClientIndex;
+template<typename CT, typename DIT> class IDataItemIndex;
 
 struct SystemContext {
-    IDataItemSubscription *mSubscriptionObj;
-    IFrameworkActionReq *mFrameworkActionReqObj;
-    const MsgTask *mMsgTask;
+    IDataItemSubscription* mSubscriptionObj;
+    IFrameworkActionReq* mFrameworkActionReqObj;
+    const MsgTask* mMsgTask;
 
     inline SystemContext() :
         mSubscriptionObj(NULL),
@@ -66,6 +64,8 @@ struct SystemContext {
         mMsgTask(NULL) {}
 };
 
+typedef map<IDataItemObserver*, list<DataItemId>> ObserverReqCache;
+
 // Clients wanting to get data from OS/Framework would need to
 // subscribe with OSObserver using IDataItemSubscription interface.
 // Such clients would need to implement IDataItemObserver interface
@@ -80,252 +80,54 @@ public:
     ~SystemStatusOsObserver();
 
     // To set the subscription object
-    inline void setSubscriptionObj(IDataItemSubscription *subscriptionObj) {
-        mContext.mSubscriptionObj = subscriptionObj;
-    };
+    virtual void setSubscriptionObj(IDataItemSubscription* subscriptionObj);
 
     // To set the framework action request object
-    inline void setFrameworkActionReqObj(IFrameworkActionReq *frameworkActionReqObj) {
+    inline void setFrameworkActionReqObj(IFrameworkActionReq* frameworkActionReqObj) {
         mContext.mFrameworkActionReqObj = frameworkActionReqObj;
     }
 
-    // IDataItemObserver Overrides
-    virtual void getName (string & name);
-    virtual void notify (const std::list <IDataItemCore *> & dlist);
-
     // IDataItemSubscription Overrides
-    virtual void subscribe (const std :: list <DataItemId> & l, IDataItemObserver * client);
-    virtual void updateSubscription
-    (
-        const std :: list <DataItemId> & l,
-        IDataItemObserver * client
-    );
-    virtual void requestData
-    (
-        const std :: list <DataItemId> & l,
-        IDataItemObserver * client
-    );
-    virtual void unsubscribe (const std :: list <DataItemId> & l, IDataItemObserver * client);
-    virtual void unsubscribeAll (IDataItemObserver * client);
+    virtual void subscribe(const list<DataItemId>& l, IDataItemObserver* client);
+    virtual void updateSubscription(const list<DataItemId>& l, IDataItemObserver* client);
+    virtual void requestData(const list<DataItemId>& l, IDataItemObserver* client);
+    virtual void unsubscribe(const list<DataItemId>& l, IDataItemObserver* client);
+    virtual void unsubscribeAll(IDataItemObserver* client);
+
+    // IDataItemObserver Overrides
+    virtual void notify(const list<IDataItemCore*>& dlist);
+    inline virtual void getName(string& name) {
+        name = mAddress;
+    }
 
     // IFrameworkActionReq Overrides
-    virtual void turnOn (DataItemId dit, int timeOut = 0);
-    virtual void turnOff (DataItemId dit);
+    virtual void turnOn(DataItemId dit, int timeOut = 0);
+    virtual void turnOff(DataItemId dit);
 
 private:
-
-    SystemContext                                        mContext;
-    const string                                         mAddress;
-    IClientIndex <IDataItemObserver *, DataItemId>      *mClientIndex;
-    IDataItemIndex <IDataItemObserver *, DataItemId>    *mDataItemIndex;
-    map < DataItemId, IDataItemCore * >                  mDataItemCache;
-    map < DataItemId, int >                              mActiveRequestCount;
-
-    // Nested types
-    // Messages
-    struct HandleMsgBase : public LocMsg {
-        HandleMsgBase (SystemStatusOsObserver * parent);
-        virtual ~HandleMsgBase ();
-        // Data members
-        SystemStatusOsObserver * mParent;
-    };
+    SystemContext                                    mContext;
+    const string                                     mAddress;
+    IClientIndex<IDataItemObserver*, DataItemId>*    mClientIndex;
+    IDataItemIndex<IDataItemObserver*, DataItemId>*  mDataItemIndex;
+    map<DataItemId, IDataItemCore*>                  mDataItemCache;
+    map<DataItemId, int>                             mActiveRequestCount;
+
+    // Cache the subscribe and requestData till subscription obj is obtained
+    ObserverReqCache mSubscribeReqCache;
+    ObserverReqCache mReqDataCache;
+    void cacheObserverRequest(ObserverReqCache& reqCache,
+            const list<DataItemId>& l, IDataItemObserver* client);
 
     // Helpers
-    int sendFirstResponse
-    (
-        const list <DataItemId> & l,
-        IDataItemObserver * to
-    );
-
-    int sendCachedDataItems
-    (
-        const list <DataItemId> & l,
-        IDataItemObserver * to
-    );
-
-    int updateCache (IDataItemCore * d, bool &dataItemUpdated);
-    void logMe (const list <DataItemId> & l);
-
-    // Messages
-    struct HandleClientMsg : public LocMsg {
-        HandleClientMsg (SystemStatusOsObserver * parent, IDataItemObserver * client);
-        virtual ~HandleClientMsg ();
-        // Data Members
-        SystemStatusOsObserver * mParent;
-        IDataItemObserver * mClient;
-    };
-
-    struct HandleSubscribeReq : public HandleClientMsg  {
-        HandleSubscribeReq (SystemStatusOsObserver * parent,
-                           const list <DataItemId> & l,
-                           IDataItemObserver * client);
-        virtual ~HandleSubscribeReq ();
-        void proc () const;
-        // Data members
-        const list <DataItemId> mDataItemList;
-    };
-
-    struct HandleUpdateSubscriptionReq : public HandleClientMsg  {
-        HandleUpdateSubscriptionReq (SystemStatusOsObserver * parent,
-                                    const list <DataItemId> & l,
-                                    IDataItemObserver * client);
-        virtual ~HandleUpdateSubscriptionReq ();
-        void proc () const;
-        // Data members
-        const list <DataItemId> mDataItemList;
-    };
-
-    struct HandleRequestData : public HandleClientMsg {
-       HandleRequestData (SystemStatusOsObserver * parent,
-                          const list <DataItemId> & l,
-                          IDataItemObserver * client);
-       virtual ~HandleRequestData ();
-       void proc () const;
-       const list <DataItemId> mDataItemList;
-    };
-
-    struct HandleUnsubscribeReq : public HandleClientMsg  {
-        HandleUnsubscribeReq (SystemStatusOsObserver * parent,
-                             const list <DataItemId> & l,
-                             IDataItemObserver * client);
-        virtual ~HandleUnsubscribeReq ();
-        void proc () const;
-        // Data members
-        const list <DataItemId> mDataItemList;
-    };
-
-    struct HandleUnsubscribeAllReq : public HandleClientMsg  {
-        HandleUnsubscribeAllReq
-        (
-            SystemStatusOsObserver * parent,
-            IDataItemObserver * client
-        );
-        virtual ~HandleUnsubscribeAllReq ();
-        void proc () const;
-    };
-
-    struct HandleNotify : public HandleMsgBase {
-        HandleNotify (SystemStatusOsObserver * parent, list <IDataItemCore *> dlist);
-        virtual ~HandleNotify ();
-        void getListOfClients
-        (
-            const list <DataItemId> & dlist,
-            list <IDataItemObserver *> & clients
-        ) const;
-        void proc () const;
-        // Data members
-        list <IDataItemCore *> mDList;
-    };
-
-    struct HandleTurnOn : public HandleMsgBase  {
-        HandleTurnOn (SystemStatusOsObserver * parent,
-                          const DataItemId dit,
-                          const int timeOut);
-        virtual ~HandleTurnOn ();
-        void proc () const;
-        // Data members
-        DataItemId mDataItemId;
-        int mTimeOut;
-    };
-
-    struct HandleTurnOff : public HandleMsgBase  {
-        HandleTurnOff (SystemStatusOsObserver * parent,const DataItemId dit);
-        virtual ~HandleTurnOff ();
-        void proc () const;
-        // Data members
-        DataItemId mDataItemId;
-    };
-
-};
-
-
-/******************************************************************************
- Messages
-******************************************************************************/
-// Ctors
-inline SystemStatusOsObserver :: HandleMsgBase :: HandleMsgBase (SystemStatusOsObserver * parent)
-:
-mParent (parent)
-{}
-
-inline SystemStatusOsObserver :: HandleClientMsg :: HandleClientMsg
-(
-    SystemStatusOsObserver * parent,
-    IDataItemObserver * client
-)
-:
-mParent (parent),
-mClient (client)
-{}
-
-inline SystemStatusOsObserver :: HandleSubscribeReq :: HandleSubscribeReq
- (SystemStatusOsObserver * parent, const list <DataItemId> & l, IDataItemObserver * client)
-:
-HandleClientMsg (parent, client), mDataItemList (l)
-{}
-
-inline SystemStatusOsObserver :: HandleUpdateSubscriptionReq :: HandleUpdateSubscriptionReq
- (SystemStatusOsObserver * parent, const list <DataItemId> & l, IDataItemObserver * client)
-:
-HandleClientMsg (parent, client), mDataItemList (l)
-{}
-
-inline SystemStatusOsObserver :: HandleRequestData :: HandleRequestData
- (SystemStatusOsObserver * parent, const list <DataItemId> & l, IDataItemObserver * client)
-:
-HandleClientMsg (parent, client), mDataItemList (l)
-{}
-
-inline SystemStatusOsObserver :: HandleUnsubscribeReq :: HandleUnsubscribeReq
- (SystemStatusOsObserver * parent, const list <DataItemId> & l, IDataItemObserver * client)
-:
-HandleClientMsg (parent, client), mDataItemList (l)
-{}
-
-inline SystemStatusOsObserver :: HandleUnsubscribeAllReq :: HandleUnsubscribeAllReq
- (SystemStatusOsObserver * parent, IDataItemObserver * client)
-:
-HandleClientMsg (parent, client)
-{}
-
-inline SystemStatusOsObserver :: HandleNotify :: HandleNotify
- (SystemStatusOsObserver * parent, list <IDataItemCore *> dlist)
-:
-HandleMsgBase (parent), mDList (dlist)
-{}
-
-inline SystemStatusOsObserver :: HandleTurnOn :: HandleTurnOn
- (SystemStatusOsObserver * parent, const DataItemId dit,const int timeOut)
-:
-HandleMsgBase (parent), mDataItemId (dit), mTimeOut (timeOut)
-{}
-
-inline SystemStatusOsObserver :: HandleTurnOff :: HandleTurnOff
- (SystemStatusOsObserver * parent, const DataItemId dit)
-:
-HandleMsgBase (parent), mDataItemId (dit)
-{}
-
-// Dtors
-inline SystemStatusOsObserver :: HandleMsgBase :: ~HandleMsgBase () {}
-inline SystemStatusOsObserver :: HandleClientMsg :: ~HandleClientMsg () {}
-inline SystemStatusOsObserver :: HandleSubscribeReq :: ~HandleSubscribeReq () {}
-inline SystemStatusOsObserver :: HandleUpdateSubscriptionReq :: ~HandleUpdateSubscriptionReq() {}
-inline SystemStatusOsObserver :: HandleRequestData :: ~HandleRequestData() {}
-inline SystemStatusOsObserver :: HandleUnsubscribeReq :: ~HandleUnsubscribeReq () {}
-inline SystemStatusOsObserver :: HandleUnsubscribeAllReq :: ~HandleUnsubscribeAllReq () {}
-
-inline SystemStatusOsObserver :: HandleNotify :: ~HandleNotify () {
-    list <IDataItemCore *> :: iterator it = mDList.begin ();
-    for (; it != mDList.end (); ++it) {
-        delete *it;
-        *it = NULL;
+    void sendFirstResponse(const list<DataItemId>& l, IDataItemObserver* to);
+    void sendCachedDataItems(const list<DataItemId>& l, IDataItemObserver* to);
+    void updateCache(IDataItemCore* d, bool& dataItemUpdated);
+    inline void logMe(const list<DataItemId>& l) {
+        for (auto id : l) {
+            LOC_LOGD("DataItem %d", id);
+        }
     }
-}
-
-inline SystemStatusOsObserver :: HandleTurnOn :: ~HandleTurnOn () {}
-inline SystemStatusOsObserver :: HandleTurnOff :: ~HandleTurnOff () {}
-
+};
 
 } // namespace loc_core
 
diff --git a/gnss/GnssAdapter.cpp b/gnss/GnssAdapter.cpp
index d4ffcb2..809e27d 100644
--- a/gnss/GnssAdapter.cpp
+++ b/gnss/GnssAdapter.cpp
@@ -67,7 +67,8 @@ GnssAdapter::GnssAdapter() :
     mAgpsManager(),
     mAgpsCbInfo(),
     mSystemStatus(SystemStatus::getInstance(mMsgTask)),
-    mServerUrl("")
+    mServerUrl(""),
+    mXtraObserver(mSystemStatus->getOsObserver(), mMsgTask)
 {
     LOC_LOGD("%s]: Constructor %p", __func__, this);
     mUlpPositionMode.mode = LOC_POSITION_MODE_INVALID;
diff --git a/gnss/GnssAdapter.h b/gnss/GnssAdapter.h
index 3cb2c64..fb50f28 100644
--- a/gnss/GnssAdapter.h
+++ b/gnss/GnssAdapter.h
@@ -106,11 +106,11 @@ class GnssAdapter : public LocAdapterBase {
     // This must be initialized via initAgps()
     AgpsManager mAgpsManager;
     AgpsCbInfo mAgpsCbInfo;
-    XtraSystemStatusObserver mXtraObserver;
 
     /* === SystemStatus ===================================================================== */
     SystemStatus* mSystemStatus;
     std::string mServerUrl;
+    XtraSystemStatusObserver mXtraObserver;
 
     /*==== CONVERSION ===================================================================*/
     static void convertOptions(LocPosMode& out, const LocationOptions& options);
@@ -280,10 +280,6 @@ public:
     void injectLocationCommand(double latitude, double longitude, float accuracy);
     void injectTimeCommand(int64_t time, int64_t timeReference, int32_t uncertainty);
 
-    inline void updateConnectionStatusCommand(bool connected, uint8_t type) {
-        mXtraObserver.updateConnectionStatus(connected, type);
-    }
-
 };
 
 #endif //GNSS_ADAPTER_H
diff --git a/gnss/XtraSystemStatusObserver.cpp b/gnss/XtraSystemStatusObserver.cpp
index 58a8522..ce08f64 100644
--- a/gnss/XtraSystemStatusObserver.cpp
+++ b/gnss/XtraSystemStatusObserver.cpp
@@ -45,40 +45,55 @@
 #include <sstream>
 #include <XtraSystemStatusObserver.h>
 #include <LocAdapterBase.h>
+#include <DataItemId.h>
+#include <DataItemsFactoryProxy.h>
 
-using namespace std;
 using namespace loc_core;
 
 #define XTRA_HAL_SOCKET_NAME "/data/vendor/location/xtra/socket_hal_xtra"
 
 bool XtraSystemStatusObserver::updateLockStatus(uint32_t lock) {
-    std::stringstream ss;
+    stringstream ss;
     ss <<  "gpslock";
     ss << " " << lock;
     ss << "\n"; // append seperator
     return ( sendEvent(ss) );
 }
 
-bool XtraSystemStatusObserver::updateConnectionStatus(bool connected, uint8_t type) {
-    std::stringstream ss;
+bool XtraSystemStatusObserver::updateConnectionStatus(bool connected, uint32_t type) {
+    stringstream ss;
     ss <<  "connection";
     ss << " " << (connected ? "1" : "0");
     ss << " " << (int)type;
     ss << "\n"; // append seperator
     return ( sendEvent(ss) );
 }
+bool XtraSystemStatusObserver::updateTac(const string& tac) {
+    stringstream ss;
+    ss <<  "tac";
+    ss << " " << tac.c_str();
+    ss << "\n"; // append seperator
+    return ( sendEvent(ss) );
+}
+
+bool XtraSystemStatusObserver::updateMccMnc(const string& mccmnc) {
+    stringstream ss;
+    ss <<  "mncmcc";
+    ss << " " << mccmnc.c_str();
+    ss << "\n"; // append seperator
+    return ( sendEvent(ss) );
+}
 
-bool XtraSystemStatusObserver::sendEvent(std::stringstream& event) {
+bool XtraSystemStatusObserver::sendEvent(const stringstream& event) {
     int socketFd = createSocket();
     if (socketFd < 0) {
         LOC_LOGe("XTRA unreachable. sending failed.");
         return false;
     }
 
-    const std::string& data = event.str();
+    const string& data = event.str();
     int remain = data.length();
     ssize_t sent = 0;
-
     while (remain > 0 &&
           (sent = ::send(socketFd, data.c_str() + (data.length() - remain),
                        remain, MSG_NOSIGNAL)) > 0) {
@@ -125,3 +140,95 @@ void XtraSystemStatusObserver::closeSocket(const int socketFd) {
         }
     }
 }
+
+void XtraSystemStatusObserver::subscribe(bool yes)
+{
+    // Subscription data list
+    list<DataItemId> subItemIdList;
+    subItemIdList.push_back(NETWORKINFO_DATA_ITEM_ID);
+    subItemIdList.push_back(MCCMNC_DATA_ITEM_ID);
+
+    if (yes) {
+        mSystemStatusObsrvr->subscribe(subItemIdList, this);
+
+        list<DataItemId> reqItemIdList;
+        reqItemIdList.push_back(TAC_DATA_ITEM_ID);
+
+        mSystemStatusObsrvr->requestData(reqItemIdList, this);
+
+    } else {
+        mSystemStatusObsrvr->unsubscribe(subItemIdList, this);
+    }
+}
+
+// IDataItemObserver overrides
+void XtraSystemStatusObserver::getName(string& name)
+{
+    name = "XtraSystemStatusObserver";
+}
+
+void XtraSystemStatusObserver::notify(const list<IDataItemCore*>& dlist)
+{
+    struct handleOsObserverUpdateMsg : public LocMsg {
+        XtraSystemStatusObserver* mXtraSysStatObj;
+        list <IDataItemCore*> mDataItemList;
+
+        inline handleOsObserverUpdateMsg(XtraSystemStatusObserver* xtraSysStatObs,
+                const list<IDataItemCore*>& dataItemList) :
+                mXtraSysStatObj(xtraSysStatObs) {
+            for (auto eachItem : dataItemList) {
+                IDataItemCore* dataitem = DataItemsFactoryProxy::createNewDataItem(
+                        eachItem->getId());
+                if (NULL == dataitem) {
+                    break;
+                }
+                // Copy the contents of the data item
+                dataitem->copy(eachItem);
+
+                mDataItemList.push_back(dataitem);
+            }
+        }
+
+        inline ~handleOsObserverUpdateMsg() {
+            for (auto each : mDataItemList) {
+                delete each;
+            }
+        }
+
+        inline void proc() const {
+            for (auto each : mDataItemList) {
+                switch (each->getId())
+                {
+                    case NETWORKINFO_DATA_ITEM_ID:
+                    {
+                        SystemStatusNetworkInfo* networkInfo =
+                                reinterpret_cast<SystemStatusNetworkInfo*>(each);
+                        mXtraSysStatObj->updateConnectionStatus(networkInfo->mConnected,
+                                networkInfo->mType);
+                    }
+                    break;
+
+                    case TAC_DATA_ITEM_ID:
+                    {
+                        SystemStatusTac* tac = reinterpret_cast<SystemStatusTac*>(each);
+                        mXtraSysStatObj->updateTac(tac->mValue);
+                    }
+                    break;
+
+                    case MCCMNC_DATA_ITEM_ID:
+                    {
+                        SystemStatusMccMnc* mccmnc = reinterpret_cast<SystemStatusMccMnc*>(each);
+                        mXtraSysStatObj->updateMccMnc(mccmnc->mValue);
+                    }
+                    break;
+
+                    default:
+                    break;
+                }
+            }
+        }
+    };
+    mMsgTask->sendMsg(new (nothrow) handleOsObserverUpdateMsg(this, dlist));
+}
+
+
diff --git a/gnss/XtraSystemStatusObserver.h b/gnss/XtraSystemStatusObserver.h
index e49f17b..42f49b5 100644
--- a/gnss/XtraSystemStatusObserver.h
+++ b/gnss/XtraSystemStatusObserver.h
@@ -29,25 +29,42 @@
 #ifndef XTRA_SYSTEM_STATUS_OBS_H
 #define XTRA_SYSTEM_STATUS_OBS_H
 
-#include <stdint.h>
+#include <cinttypes>
+#include <MsgTask.h>
 
+using namespace std;
+using loc_core::IOsObserver;
+using loc_core::IDataItemObserver;
+using loc_core::IDataItemCore;
 
-class XtraSystemStatusObserver {
+
+class XtraSystemStatusObserver : public IDataItemObserver {
 public :
     // constructor & destructor
-    XtraSystemStatusObserver() {
+    inline XtraSystemStatusObserver(IOsObserver* sysStatObs, const MsgTask* msgTask):
+            mSystemStatusObsrvr(sysStatObs), mMsgTask(msgTask) {
+        subscribe(true);
     }
+    inline XtraSystemStatusObserver() {};
+    inline virtual ~XtraSystemStatusObserver() { subscribe(false); }
 
-    virtual ~XtraSystemStatusObserver() {
-    }
+    // IDataItemObserver overrides
+    inline virtual void getName(string& name);
+    virtual void notify(const list<IDataItemCore*>& dlist);
 
     bool updateLockStatus(uint32_t lock);
-    bool updateConnectionStatus(bool connected, uint8_t type);
+    bool updateConnectionStatus(bool connected, uint32_t type);
+    bool updateTac(const string& tac);
+    bool updateMccMnc(const string& mccmnc);
+    inline const MsgTask* getMsgTask() { return mMsgTask; }
+    void subscribe(bool yes);
 
 private:
     int createSocket();
     void closeSocket(const int32_t socketFd);
-    bool sendEvent(std::stringstream& event);
+    bool sendEvent(const stringstream& event);
+    IOsObserver*    mSystemStatusObsrvr;
+    const MsgTask* mMsgTask;
 
 };
 
diff --git a/gnss/location_gnss.cpp b/gnss/location_gnss.cpp
index a99d8ef..19399de 100644
--- a/gnss/location_gnss.cpp
+++ b/gnss/location_gnss.cpp
@@ -253,6 +253,6 @@ static void getDebugReport(GnssDebugReport& report) {
 
 static void updateConnectionStatus(bool connected, uint8_t type) {
     if (NULL != gGnssAdapter) {
-        gGnssAdapter->updateConnectionStatusCommand(connected, type);
+        gGnssAdapter->getSystemStatus()->eventConnectionStatus(connected, type);
     }
 }
\ No newline at end of file