Fix default theme loading issue (#98)

Co-authored-by: Dharmakeerthi Lasantha <tcdlpds@gmail.com>
Co-authored-by: Pahansith Gunathilake <pahansith@entgra.io>
Reviewed-on: community/device-mgt-core#98
Co-authored-by: Lasantha Dharmakeerthi <lasantha@entgra.io>
Co-committed-by: Lasantha Dharmakeerthi <lasantha@entgra.io>

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/WhiteLabelServiceImpl.java

@@ -127,13 +127,9 @@ public class WhiteLabelServiceImpl implements WhiteLabelService {
             WhiteLabelTheme whiteLabelTheme = DeviceMgtAPIUtils.getWhiteLabelManagementService().getWhiteLabelTheme(tenantDomain);
             return Response.status(Response.Status.CREATED).entity(whiteLabelTheme).build();
         } catch (MetadataManagementException e) {
-            String msg = "Error occurred while deleting whitelabel for tenant";
+            String msg = "Error occurred while getting whitelabel for tenant";
             log.error(msg, e);
             return Response.status(Response.Status.INTERNAL_SERVER_ERROR).entity(msg).build();
-        } catch (NotFoundException e) {
-            String msg = "Not white label theme configured for this tenant";
-            log.error(msg, e);
-            return Response.status(Response.Status.BAD_REQUEST).entity(msg).build();
         } catch (DeviceManagementException e) {
             String msg = "Error occurred while retrieving tenant details of whitelabel";
             log.error(msg, e);

components/device-mgt/org.wso2.carbon.device.mgt.common/src/main/java/org/wso2/carbon/device/mgt/common/metadata/mgt/WhiteLabelManagementService.java

@@ -79,5 +79,5 @@ public interface WhiteLabelManagementService {
      * This method is useful to get existing white label theme
      * @throws MetadataManagementException if error while getting existing white label theme
      */
-    WhiteLabelTheme getWhiteLabelTheme(String tenantDomain) throws MetadataManagementException, NotFoundException, DeviceManagementException;
+    WhiteLabelTheme getWhiteLabelTheme(String tenantDomain) throws MetadataManagementException, DeviceManagementException;
 }

components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/metadata/mgt/WhiteLabelManagementServiceImpl.java

@@ -26,7 +26,6 @@ import org.apache.http.HttpResponse;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClients;
-import org.wso2.carbon.context.CarbonContext;
 import org.wso2.carbon.context.PrivilegedCarbonContext;
 import org.wso2.carbon.device.mgt.common.Base64File;
 import org.wso2.carbon.device.mgt.common.FileResponse;
@@ -329,10 +328,6 @@ public class WhiteLabelManagementServiceImpl implements WhiteLabelManagementServ
             } finally {
                 MetadataManagementDAOFactory.closeConnection();
             }
-        } catch (NotFoundException e) {
-            String msg = "Error occurred while retrieving existing white label theme";
-            log.error(msg, e);
-            throw new MetadataManagementException(msg, e);
         } catch (DeviceManagementException e) {
             String msg = "Error occurred while getting tenant details of white label";
             log.error(msg, e);
@@ -429,20 +424,36 @@ public class WhiteLabelManagementServiceImpl implements WhiteLabelManagementServ
     }
 
     @Override
-    public WhiteLabelTheme getWhiteLabelTheme(String tenantDomain) throws MetadataManagementException, NotFoundException, DeviceManagementException {
+    public WhiteLabelTheme getWhiteLabelTheme(String tenantDomain) throws MetadataManagementException, DeviceManagementException {
         int tenantId = DeviceManagerUtil.getTenantId(tenantDomain);
         if (log.isDebugEnabled()) {
             log.debug("Retrieving whitelabel theme for tenant: " + tenantId);
         }
-        try {
-            MetadataManagementDAOFactory.openConnection();
-            Metadata metadata =  metadataDAO.getMetadata(tenantId, MetadataConstants.WHITELABEL_META_KEY);
+        Metadata metadata = getWhiteLabelMetaData(tenantId);
+        if (metadata == null) {
+            addDefaultWhiteLabelThemeIfNotExist(tenantId);
+            metadata = getWhiteLabelMetaData(tenantId);
             if (metadata == null) {
-                String msg = "Whitelabel theme not found for tenant: " + tenantId;
+                String msg = "Whitelabel theme not found for tenant: " + tenantId + ". Further, Default White Label " +
+                        "Theming Adding step failed.";
                 log.error(msg);
-                throw new NotFoundException(msg);
+                throw new MetadataManagementException(msg);
             }
-            return new Gson().fromJson(metadata.getMetaValue(), WhiteLabelTheme.class);
+        }
+        return new Gson().fromJson(metadata.getMetaValue(), WhiteLabelTheme.class);
+    }
+
+    /**
+     * Load White label Meta Data for given tenant Id.
+     * @param tenantId Id of the tenant
+     * @return {@link Metadata}
+     * @throws MetadataManagementException if an error occurred while getting Meta-Data info from Database for a
+     * given tenant ID.
+     */
+    private Metadata getWhiteLabelMetaData (int tenantId) throws MetadataManagementException {
+        try {
+            MetadataManagementDAOFactory.openConnection();
+            return metadataDAO.getMetadata(tenantId, MetadataConstants.WHITELABEL_META_KEY);
         } catch (MetadataManagementDAOException e) {
             String msg = "Error occurred while retrieving white label theme for tenant:" + tenantId;
             log.error(msg, e);