Add comparable bytes to row decorator

[EricBorczuk]

What this PR does:

Which issue(s) this PR fixes:
Fixes #1716

Checklist

• Changes manually tested
• Automated Tests added/updated
• Documentation added/updated
• CLA Signed: DataStax CLA

[EricBorczuk]

I decided to use Stream here because ByteSource (the class that comparable bytes returns) is best represented as an iterable of bytes with no known length, rather than a list or array - so the consumer of this method would be responsible for either consuming the whole stream and creating a list, or passing the stream along (maybe gRPC supports this?)

[tatu-at-datastax]

But isn't Stream<Byte> very inefficient? Byte is wrapper type and that seems ... like a very inefficient abstraction, and at least wrt performance worse than ByteSource.
Even plain old byte[] seems better unless I am missing something obvious (byte array can be wrapped as ByteBuffer etc)

[EricBorczuk]

ah I should use ByteBuffer 🤦 idk what I was thinking

[tatu-at-datastax]

Yeah that's a solid choice. Np! :)

[ivansenic]

Yep good points @tatu-at-datastax

[ivansenic]

Looks good, but test needs to be better..

[ivansenic]

this is not enough, we need the same test as in the testRowDecorator, just confirming that bytes are created is not enough, we need to confirm that comapring is done correctly.. should be one-to-one with the testRowDecorator and then test comparing using a unsigned bytes comparator .. And sure only active for DSE now..

[EricBorczuk]

I added a better test for this - but in order to do so I had to have ByteComparable in scope and so had to add a DSE dependency to the persistence-test module...hope that's ok.

Maybe it can be reconfigured to only import that package

[ivansenic]

Tests still not looking good, new dependency is definitely not a good choice.

[ivansenic]

This is definitely not needed.. Will comment on the test more..

[ivansenic]

You shouldn't depend on these DSE related interfaces? What's the issue with comparing bytes in unsigned order directly?

I know there is UnsignedBytes in Guava, this should have something we could use.. Or use something like this (take from PureJavaOperations class):

    @Override
    public int compare(ByteBuffer buffer1, ByteBuffer buffer2) {
      int end1 = buffer1.limit();
      int end2 = buffer2.limit();
      for (int i = buffer1.position(), j = buffer2.position(); i < end1 && j < end2; i++, j++) {
        int a = (buffer1.get(i) & 0xff);
        int b = (buffer2.get(j) & 0xff);
        if (a != b) {
          return a - b;
        }
      }
      return buffer1.remaining() - buffer2.remaining();
    }

[ivansenic]

Not sure what's going on here, why simply not using and adapting the code from the above method:

while (it1.hasNext()) {
      assertThat(it2.hasNext()).isTrue();
      Row r1 = it1.next();
      Row r2 = it2.next();
      first = first == null ? r1 : first;
      last = r1;
      assertEq(r1, r2, dec1, dec2);
      if (p1 == null) {
        p1 = r1;
      }
      assertGtEq(r1, p1, dec1, dec2);
    }
    assertThat(it2.hasNext()).isFalse();
    assertGt(last, first, dec1, dec2);
}    

[ivansenic]

Yup that's it..