Multimap with navigable keys and arbitrary semantic.

[JackieKu]

• TreeMultimap supports navigable keys but the semantic of values are limited to SortedSet.
• MultimapBuilder.treeKeys().arrayListValues() is not navigable.

This is too restrictive for many usages requiring navigable keys. In our case the values are simply not sortable, could be duplicated, but the insertion order should be maintained.

An API like MultimapBuilder.navigableKeys() would be appreciated.

[cpovirk]

Sorry that this has gotten no response. You might be able to get some navigable features from the MultimapBuilder.treeKeys().arrayListValues() multimap's asMap() view (though you'd have to cast). We should still give some thought to whether we could provide a better API.