Reporting if no match found in all new entries from a feed poll

[andrejtokarcik]

If there is no match in all entries of a feed, the user sees just the "Polling feed ..." message followed by nothing else (with info-level logging). That is confusing as it's not clear whether it's just the pattern-matching taking so long or whether there is actually no match. In the latter case there should be a clear message.

In other words, when a feed is polled and none of the new entries is matched by the pattern, a relevant summary info message should be recorded: regarding the state of all the new entries considered in common, not each of them individually (which would just flood the log).

This is currently difficult to implement because FeedHandler emits its NewEntry messages separately for each new entry and therefore Manager is not aware about the total number of new entries found in the feed during this particular poll. Even then, Manager would probably have to store the number of new entries found (as reported by FeedHandler) per feed in a map and decrement on each NoMatch message (would have to be introduced) received from EntryHandler.

Another approach could involve ActorContext.setReceiveTimeout: if no NewEntry was received during a period of time, all the new entries would be considered non-matching and the fact reported.

P.S.: Reporting the case that no new entry is found in FeedHandler (as opposed to the collection of EntryHandlers) is easy and should be done immediately.