Added IService QObject derived class for emiting Qt signals from service objects.

core/service.h

@@ -12,14 +12,15 @@
 
 #include "core_global.h"
 #include "context.h"
+#include "iservice.h"
 
 #include "transaction.h"
 
 template<class T>
-class Service
+class Service : public IService
 {
 public:
-    Service() { }
+    explicit Service(QObject *parent = NULL) :IService(parent) { }
 
     explicit Service(const QString &pluginId) {
         m_pluginId = pluginId;
@@ -31,14 +32,23 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        odb::result<T> res = db->template query<T>();
-
         QList<QSharedPointer<T> > ret;
-        for (typename odb::result<T>::iterator it = res.begin(); it != res.end(); it++) {
-            ret.append(it.load());
+
+        try
+        {
+            odb::result<T> res = db->template query<T>();
+
+            for (typename odb::result<T>::iterator it = res.begin(); it != res.end(); it++) {
+                ret.append(it.load());
+            }
+
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
         }
 
-        tx.commit();
         return ret;
     }
 
@@ -48,8 +58,19 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        db->persist(entity);
-        tx.commit();
+
+        try
+        {
+            db->persist(entity);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+            return;
+        }
+
+        emit dataChanged();
     }
 
     void update(QSharedPointer<T> entity) {
@@ -58,8 +79,18 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        db->update(entity);
-        tx.commit();
+
+        try
+        {
+            db->update(entity);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+        }
+
+        emit dataChanged();
     }
 
     QSharedPointer<T> loadById(int id) {
@@ -68,8 +99,18 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        QSharedPointer<T> entity = db->template load<T>(id);
-        tx.commit();
+        QSharedPointer<T> entity;
+
+        try
+        {
+            entity = db->template load<T>(id);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+        }
+
         return entity;
     }
 
@@ -79,8 +120,16 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        db->erase(entity);
-        tx.commit();
+
+        try
+        {
+            db->erase(entity);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+        }
     }
 
     void setPluginId(const QString &pluginId) {