MINOR: Code cleanup Kafka Streams

[sjhajharia]

What

Code Cleanup in Streams Module

Changes

Some common changes include

• Replace the Arrays.asList() with Collections.singletonList() wherever possible
• Cleaning up some if-else blocks
• Replacing some instances of String.builder() with String operations
• Replcing some format() with printf()

Thanks!

[mjsax]

Thanks for the PR. Couple of comments. Also, can you please rebase the PR to resolve merge conflict?

[mjsax]

@sjhajharia -- do you still have interest to finish this PR?

[sjhajharia]

Hey @mjsax
Sorry, I was swamped a bit. Getting back to this, thanks for the review. I have updated the PR.
Could you pls help review again.
Thanks

[mjsax]

Thanks for the PR update. Made another pass. Just nits, but given it's a cleanup PR, guess it ok to be nitty, as the whole PR is?

Btw: I though using StringBuilder is usually recommended as it more efficient? Does this not hold any longer? For this case, we are not on the critical code path so perf does not matter much, and I agree that StringBuilder make the code harder to read... Just curious.

[mjsax]

nit: avoid unnecessary reformatting

[mjsax]

Suggested change

	assertThat("Found some over- or under-assigned tasks in the final assignment with " + numStandbyReplicas + " and max warmups " + maxWarmupReplicas + " standby replicas, stateful tasks:" + statefulTasks + ", and stateless tasks:" + statelessTasks + failureContext, misassigned, is(emptyMap()));
	assertThat(
	"Found some over- or under-assigned tasks in the final assignment with " + numStandbyReplicas +
	" and max warmups " + maxWarmupReplicas + " standby replicas, stateful tasks:" + statefulTasks +
	", and stateless tasks:" + statelessTasks + failureContext, misassigned,
	is(emptyMap())
	);

[mjsax]

Line too long.. Let's do something like this to make it easier to read.

[mjsax]

This is boarderline... maybe better to split into two lines? (similar below)

[mjsax]

Preferred formatting would be (but also ok to leave as-is):

            System.err.printf(
                "ERROR: Did not have all required configs expected  to contain %s, %s,  %s,  %s%n",
                StreamsConfig.consumerPrefix(ConsumerConfig.MAX_POLL_INTERVAL_MS_CONFIG),
                StreamsConfig.producerPrefix(ProducerConfig.RETRIES_CONFIG),
                StreamsConfig.producerPrefix(ProducerConfig.REQUEST_TIMEOUT_MS_CONFIG),
                StreamsConfig.producerPrefix(ProducerConfig.MAX_BLOCK_MS_CONFIG)
            );

[mjsax]

Thanks for the PR. Merged to trunk.