Type refinements, lots of changes, test infrastructure and more

[debasishg]

This PR does the following:

1. lots of type refinements
2. refactoring
3. test infrastructure incorporated
4. started writing tests - same ones from confluent examples

Now we have better type inference and hence better chaining of builder methods .. The following fragment is the replacement from https://github.com/confluentinc/kafka-streams-examples/blob/4.0.x/src/test/scala/io/confluent/examples/streams/StreamToTableJoinScalaIntegrationTest.scala#L144-L166

// Compute the total per region by summing the individual click counts per region. val clicksPerRegion: KTableS[String, Long] = userClicksStream // Join the stream against the table. .leftJoin(userRegionsTable, (clicks: Long, region: String) => (if (region == null) "UNKNOWN" else region, clicks)) // Change the stream from <user> -> <region, clicks> to <region> -> <clicks> .map((_: String, regionWithClicks: (String, Long)) => regionWithClicks) // Compute the total per region by summing the individual click counts per region. .groupByKey(Serialized.`with`(stringSerde, scalaLongSerde)) .reduce(_ + _)

Now need to port more tests from Confluent examples and check for exhaustivity of the APIs. Also need to document stuff.

[deanwampler]

A few comments about constant naming conventions.

[deanwampler]

What about putting "_" between the words?

[debasishg]

will do ..

[deanwampler]

Any particular reason you didn't use the same names for the properties, e.g., ACKS_CONFIG vs. ACKCONFIGURATION? I know these are values you're setting, so perhaps ACKS_CONFIG_DEFAULT?

Also, should these hard-coded defaults be a last resort, only used if no config file definitions are found (perhaps that's how it works...)?

[debasishg]

will change .. also opened an issue #11 for the config file ..

[blublinsky]

Additionally, scala 2.11 does not compile