adding default values for timestamp

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

@@ -83,6 +83,10 @@ public class ActivityProviderServiceImpl implements ActivityInfoProviderService
         long timestamp = 0;
         boolean isIfModifiedSinceSet = false;
         boolean isSinceSet = false;
+        if (log.isDebugEnabled()) {
+            log.debug("getActivities since: " + since + " , offset: " + offset + " ,limit: " + limit + " ," +
+                    "ifModifiedSince: " + ifModifiedSince);
+        }
         RequestValidationUtil.validatePaginationParameters(offset, limit);
         if (ifModifiedSince != null && !ifModifiedSince.isEmpty()) {
             Date ifSinceDate;
@@ -112,14 +116,32 @@ public class ActivityProviderServiceImpl implements ActivityInfoProviderService
             timestamp = sinceTimestamp / 1000;
         }
 
+        if (timestamp == 0) {
+            //If timestamp is not sent by the user, a default value is set, that is equal to current time-12 hours.
+            long time = System.currentTimeMillis() / 1000;
+            timestamp = time - 42300;
+        }
+        if (log.isDebugEnabled()) {
+            log.debug("getActivities final timestamp " + timestamp);
+        }
+
         List<Activity> activities;
         ActivityList activityList = new ActivityList();
         DeviceManagementProviderService dmService;
         try {
+            if (log.isDebugEnabled()) {
+                log.debug("Calling database to get activities.");
+            }
             dmService = DeviceMgtAPIUtils.getDeviceManagementService();
             activities = dmService.getActivitiesUpdatedAfter(timestamp, limit, offset);
             activityList.setList(activities);
+            if (log.isDebugEnabled()) {
+                log.debug("Calling database to get activity count.");
+            }
             int count = dmService.getActivityCountUpdatedAfter(timestamp);
+            if (log.isDebugEnabled()) {
+                log.debug("Activity count: " + count);
+            }
             activityList.setCount(count);
             if (activities == null || activities.size() == 0) {
                 if (isIfModifiedSinceSet) {