android - What is the best design pattern/architecture for my situation -

android - What is the best design pattern/architecture for my situation -

firstly, hi everyone.

so have app running on android os - clients using.

i have server + database (typical end backbone) can connect , retrieve info - pretty much repository storing info clients require in order android app run.

so basically, can suggest design pattern/architecture best suits next requirement:

(1) client(a) associated score, simple int value lets say.(like football game league) - if client(a) given score client(b), client(a) score updated

(2) client(a) can add together many friends ( clients(c,d,e,...) ) league table - client(a) league table , client(a) list of friends stored in local database on client(a) android advice.

(at point, view client(a) have connect server + database retrieve updates (very important: server never contact them allow them know there update))

(3) if 1 client(a) gives client(b) score, accrued client's(b) score.

(4) clients(c,d,e,...) have client(b) in league table need updated update when access app 1 time again , check updates, i.e: want update take place if clients(c,d,e,...) connect server (as opposed server attempting inform client update awaiting them)

note: not using google cloud messaging btw

hope makes sense , in advance comments

android design-patterns architecture multiplayer