Tagging in-app notification when the app is not running.

Hi, I have requirement to send tag while app notification arises, basically i have to keep track of notification whether they are triggering in app as per the schedule date and time. these notifications are not actually cloud notification, it's in-app notification, build within the app on schedule date.

I learned that tagging notification is not possible since there no exist of application process.

It seems to me that tagging is possible in my case, Notification services which i have constructed in android app is not going to be completely handle by OS with notification message , rather it tells app that there is alarm at this point of time and creates background service to app, this service then involves with few operation to build appropriate notification message, service is also take control over app database . it could be possible for me to have application instance to operate anything within this service.

I am thinking that, using application instance i can still post tag, but i have to understand limitations.

Any help would be greatly appreciated. Thank you.