Question

I have a guava HashMultimap like this

Multimap<String, String> multiMap = HashMultimap.create();
multiMap.put("a", "x");
multiMap.put("a", "y");
multiMap.put("b", "y");
multiMap.put("b", "z");
multiMap.put("d", "x");
multiMap.put("c", "h");

and I want to create a table with the distinct key and values. Calling

multiMap.values(); // returns x,y,y,z,x,h

but I want to the distinct set of values?.

I’m aware that Iterator.filter() is available but am unsure how it should be implmented. The expected result should be

// x,y,z,h

Answer 1

I’d just use

Sets.newHashSet(multiMap.values());

or, if you want an immutable version:

ImmutableSet.copyOf(multiMap.values());

Note that in either case you no longer have a live view of the values but a copy.