Create Guava ImmutableRangeSet from overlapping ranges

Question

Apparently Guava's ImmutableRangeSet cannot store overlapping ranges. This makes sense, but is there an interface to resolve/merge overlapping ranges and then put the resultant ranges into an ImmutableRangeSet?

Currently I'm building a TreeRangeSet, which automatically merges overlapping ranges, and passing this as an argument to ImmutableRangeSet.builder().addAll(). This process works, but it seems a little too indirect just to resolve overlapping ranges.

Answer 1

Can you be more specific about your use case? I guess you have a collection of ranges and you're trying to create ImmutableRangeSet using copyOf method, which throws IAE in case of overlapping ranges. Let's see this test case:

@Test
public void shouldHandleOverlappingRanges()
{
    //given
    ImmutableList<Range<Integer>> ranges = ImmutableList.of(
            Range.closed(0, 2),
            Range.closed(1, 4),
            Range.closed(9, 10)
    );
    //when
    ImmutableRangeSet<Integer> rangeSet = ImmutableRangeSet.copyOf(ranges);
    //then
    assertThat(rangeSet.asSet(DiscreteDomain.integers()))
            .containsOnly(0, 1, 2, 3, 4, 9, 10);
}

which fails with

java.lang.IllegalArgumentException: 
Overlapping ranges not permitted but found [0..2] overlapping [1..4]

In this case you should use unionOf instead of copyOf and it'd pass:

//when
ImmutableRangeSet<Integer> rangeSet = ImmutableRangeSet.unionOf(ranges);