Prefer subtypes of Multimap

Guava team recommends using the subinterfaces of Multimap, for the
same reasons they recommend using Set and List rather than Collection:
it documents expectations about ordering, uniqueness, and behavior of
equals. Do this across the board in Gerrit.

Mostly this is straightforward and I tried to exactly match existing
behavior where possible. However, there were a few wrinkles, where
different callers passed different subtypes to the same method.

The main one is arguments to ParameterParser#parse and
splitQueryString, where some callers used SetMultimaps (perhaps
semi-intentionally, or perhaps misunderstanding the nature of
HashMultimap). For the purposes of parameter parsing, a ListMultimap
makes more sense, because it preserves argument order and repetition.

Another instance is a couple places in ReceiveCommits and downstream
where there were SetMultimap<?, Ref>. Since Refs do not implement
equals, this is effectively the same thing as a ListMultimap, and
changing the interface no longer misleads readers into thinking there
might be some deduplication happening.

Finally, this change includes a breaking API change to the return
type of ExternalIncludedIn#getIncludedIn.

Change-Id: I5f1d15e27a32e534a6aaefe204e7a31815f4c8d7
This commit is contained in:
Dave Borowitz
2017-01-13 16:26:45 -05:00
committed by David Pursehouse
parent e5c5953205
commit 484da493b3
76 changed files with 367 additions and 355 deletions

View File

@@ -19,7 +19,7 @@ import static com.google.common.truth.Truth.assertThat;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.LinkedListMultimap;
import com.google.common.collect.Multimap;
import com.google.common.collect.ListMultimap;
import com.google.gerrit.common.UserScopedEventListener;
import com.google.gerrit.extensions.registration.DynamicSet;
import com.google.gerrit.extensions.registration.RegistrationHandle;
@@ -39,7 +39,7 @@ import org.eclipse.jgit.revwalk.RevCommit;
public class EventRecorder {
private final RegistrationHandle eventListenerRegistration;
private final Multimap<String, RefEvent> recordedEvents;
private final ListMultimap<String, RefEvent> recordedEvents;
@Singleton
public static class Factory {