Refactor planner Kafka Query

[elliVM]

Changes

Goals is to replace poll(timeout) method completely since it was causing stalls when topic had no records or was unauthorized. Old way subscribed using a pattern and then used poll() to get offsets from the meta data.

Now we use the listTopics() method to list all topics the user has access to and then filter them using a regex pattern from the query. After that we can use the resulting topics to get offsets for all the partitions.

Class responsibilities

• CombinedTopicPartitions combined partitions of a list of topics
• KafkaQueryImpl implements KafkaQuery to get beginning and end offsets of all topics partitions for a query
• KafkaSubscriptionPatternFromQuery parses a regex pattern from incoming query XML
• RegexMatchingKafkaTopics filters topics using a regex pattern
• SetOnce allows for delayed setting of a immutable state, used to store a snapshot of Kafka topics fetched from server
• TopicPartitions provides partitions of a topic
• TopicsFromKafka lists all topics in Kafka available for user