How to sort guava multimap? (KEY=DATE)

Question

I have a

Multimap<Date,Invoice> multimap = ArrayListMultimap.create();

from guava. I was wondering how to SORT the the Date key in the multimap.

Currently, I'm doing this:

        Iterator<Date> dateItr = multimap.keySet().iterator();
        Set<Date> treeSet = new TreeSet<Date>(Collections.reverseOrder());

and later I loop through the treeSet iterator. Any idea how to avoid this circumvention?

[TreeMultimap](http://guava-libraries.googlecode.com/svn/tags/release03/javadoc/com/google/common/collect/TreeMultimap.html) — Beau Grantham, May 14 '12 at 19:21

Louis Wasserman · Accepted Answer · 2015-08-20T03:45:25.407

16

Guava team member here.

Use TreeMultimap, or if you need to map into Lists, use MultimapBuilder:

return MultimapBuilder.treeKeys().arrayListValues().build()

edited Aug 20 '15 at 03:45

answered May 14 '12 at 19:35

Louis Wasserman

I tried the your code but I can't figure it out how to construct it with my classes. – adhg May 17 '12 at 16:10
Can you please write the line of code that relates to KEY=Date and V=Invoice. Thanks! – adhg May 17 '12 at 16:17
Um. Replace the letter `K` with `Date` and `V` with `Invoice`, and that'll work. – Louis Wasserman May 17 '12 at 21:36
Post your revised code in the question, then, because you shouldn't get a compile error. – Louis Wasserman May 21 '12 at 20:55
You're storing it in a `TreeMultimap` variable; of course that's not going to work. Put it in a `ListMultimap` and it'll be fine. – Louis Wasserman May 21 '12 at 21:23

1 Answers1