i'm making app (imaginary) massage center. in activity, user can click button make reservation. 1 customer must able make reservation specific date , time, have use transaction takes account current state of database handle update.
right now, doing following:
public void processviewresult(object object, string tag) { if (tag.equals("reservation")) { final reservation reservation = (reservation) object; database.getreference().runtransaction(new transaction.handler() { @override public transaction.result dotransaction(mutabledata mutabledata) { mutabledata freeslots = mutabledata.child("slots").child(reservation.getdate()); mutabledata userreservations = mutabledata.child("users") .child(reservation.getuserid()).child("reservations"); boolean isslotavailable = freeslots.haschild(reservation.gethour()); if (isslotavailable) { mutabledata.child(reservation.gethour()).setvalue(null); userreservations.child(string.valueof(reservation.hashcode())).setvalue(reservation); return transaction.success(mutabledata); } else { return transaction.abort(); } } @override public void oncomplete(databaseerror databaseerror, boolean b, datasnapshot datasnapshot) { if (databaseerror != null) { log.e(this.getclass().getsimplename(), databaseerror.tostring()); } else { log.e(this.getclass().getsimplename(), "updated successfully"); } } }); } }
there several problems approach:
1) since need update both time slots available , reservations made current customer, need snapshot of whole database. if application scaled, inefficient.
2) approach has lot of boilerplate.
can please tell me if there simpler , more elegant solution this?
