Add getEstimatedSize API to OutputCodec

[kkondaka]

Description

Add getEstimatedSize API to OutputCodec.
Returns exact or slightly more size of an event when passed through the OutputCodec.

Issues Resolved

Resolves #[Issue number to be closed when this PR is merged]

Check List

• [X ] New functionality includes testing.
• New functionality has a documentation issue. Please link to it in this PR.
  • New functionality has javadoc added
• [X ] Commits are signed with a real name per the DCO

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[dlvenable]

I left some comments.

At a high-level, I think we can get a better size estimate with the refactoring I suggested because it will account for what is already there.

[dlvenable]

Return a long.

[dlvenable]

I'm not quite sure that this will be accurate. But, I'm not sure there is anyway to really do this correctly in Parquet.

[dlvenable]

I think we need the SinkContext here.

[dlvenable]

Do you think we could have this as a default implementation and remove the concrete implementations for most of the sub-classes?

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
BinaryEncoder encoder = EncoderFactory.get().binaryEncoder(outputStream, null);
start(outputStream, event, sinkContext);
write(event);
return outputStream.toByteArray().length;

[dlvenable]

OK. If you are really ambitious, I've thought about a refactoring in the past, that could also make this more accurate.

The OutputCodec is currently designed as a single codec for all OutputStreams. However, it would make more sense for OutputCodec to be more like a factory.

public interface OutputCodec {
  public interface BoundToStreamCodec {
    void writeEvent(Event event);
    void complete();
    int getEstimatedSize();
  }
  codecFor(final OutputStream outputStream, Event event, final OutputCodecContext codecContext); // replaces start();
}

The callers use it like this:

BoundToStreamCodec codec = outputCodec.codecFor(outputStream, event, codecContext); // replaces .start()
...
for(...) {
  codec.writeEvent(event); // it already has an OutputStream so need to pass again.
}
...
codec.complete();