Kafka-15126: Range queries to accept null lower and upper bounds

[Cerchie]

Change in response to KIP-941.

Changes line 57 in the RangeQuery class file from:

public static <K, V> RangeQuery<K, V> withRange(final K lower, final K upper) {
    return new RangeQuery<>(Optional.of(lower), Optional.of(upper));
}

to

public static <K, V> RangeQuery<K, V> withRange(final K lower, final K upper) {
     return new RangeQuery<>(Optional.ofNullable(lower), Optional.ofNullable(upper));
 }

Testing strategy:

Since null values can now be entered in RangeQuerys in order to receive full scans, I changed the logic defining query starting at line 1085 in IQv2StoreIntegrationTest.java from:

        final RangeQuery<Integer, V> query;
        if (lower.isPresent() && upper.isPresent()) {
            query = RangeQuery.withRange(lower.get(), upper.get());
        } else if (lower.isPresent()) {
            query = RangeQuery.withLowerBound(lower.get());
        } else if (upper.isPresent()) {
            query = RangeQuery.withUpperBound(upper.get());
        } else {
            query = RangeQuery.withNoBounds();
        }

to

query = RangeQuery.withRange(lower.orElse(null), upper.orElse(null));

because different combinations of isPresent() in the bounds is no longer necessary.

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[bbejeck]

Thanks for the PR @Cerchie - overall, this looks good to me.
I think it would be good to update the Javadoc on the withRange(lower, upper) method to briefly describe the behavior if one or both of the parameters are null

[bbejeck]

LGTM

[bbejeck]

@Cerchie since it's been a couple of weeks for this PR can you rebase this with trunk?
Pending the related tests passing we should be able to merge

ping @vvcephei for a quick second look

[Cerchie]

closing due to merge issue, refer to #14137