kafka-streams-internals-AbstractTaskCreator.adoc

AbstractTaskCreator

AbstractTaskCreator is the base of task creators (factories) that can create stream processor tasks.

Table 1. AbstractTaskCreator Contract

Method	Description
createTask	T createTask( Consumer<byte[], byte[]> consumer, TaskId id, Set<TopicPartition> partitions) Creates a task Used exclusively when AbstractTaskCreator is requested to create tasks (when TaskManager is requested for standby or stream tasks)

Note	AbstractTaskCreator is a Java abstract class and cannot be created directly. It is created indirectly when the concrete AbstractTaskCreators are.

Table 2. AbstractTaskCreators

AbstractTaskCreator	Description
StandbyTaskCreator	Creates standby tasks
TaskCreator	Creates stream tasks

Creating Tasks — createTasks Method

Collection<T> createTasks(
  Consumer<byte[], byte[]> consumer,
  Map<TaskId, Set<TopicPartition>> tasksToBeCreated)

createTasks…​FIXME

Note	createTasks is used when TaskManager is requested for standby and stream tasks.

Creating AbstractTaskCreator Instance

AbstractTaskCreator takes the following when created:

• InternalTopologyBuilder

• StreamsConfig

• StreamsMetrics

• StateDirectory

• Kafka Sensor (to monitor task created)

• ChangelogReader

• Time

• Logger