Compare two multimaps and replace/remove values

Question

I have two multimaps with Ids and names, one is filled with information that i get from a remote service and the second has information that i have in my local database. I need to compare and synchronize them.

Multimap<Long, String> remote
Multimap<Long, String> localDB

We can assume that ids are always the same but names can vary, e.g:

remote = {1 = [Tom], 2 = [Bob , Ron], 3 = [Philip]}
local = {1 = [Tom], 2 = [Johan, Robert], 3 = [Susan]}

And what i expect to get is:

local = {1 = [Tom], 2 = [Bob , Ron], 3 = [Philip]}

how can i get it?

Check this https://stackoverflow.com/questions/32254598/how-can-i-compare-two-multimaps — Héctor M., Mar 26 '18 at 15:07
I have checked that post and it does not refer to my problem — Marcin Retek, Mar 26 '18 at 15:15
yes, but only for these that do not match in order to synchronize them — Marcin Retek, Mar 26 '18 at 15:37
@Marret To put one map into another, you can call putAll method with another map as argument. If there will be values with the same keys, value of key will be override. — Tom, Mar 26 '18 at 15:50
Looks like you not really want a sync in both directions but only from remote to local, correct? — mle, Mar 26 '18 at 16:05

score 0 · Answer 1 · answered Mar 27 '18 at 06:19

Extending the options from the comments above and assuming you'll just sync remote to local you have at least three different options:

set one list itself on another: local = remote;
remove all values from local which are not in remote and then do local.putAll(remote);
copy the contents from remote to local: local = ImmutableListMultimap.copyOf(remote);

Compare two multimaps and replace/remove values

1 Answers1