Page History

package org.apache.kafka.streams.processor.assignment; 

/**
 * A simple container class for the assignor to return the desired placement of active and standby tasks on KafkaStreams clients
  */
public class KafkaStreamsAssignment {

  /* 
   * Construct an instance of KafkaStreamsAssignment with this processId and the given set of
   * assigned tasks. If you want this KafkaStreams client to request a followup rebalance, you
   * can set the followupRebalanceDeadline via the {@link #withFollowupRebalance(Instant)} API.
   *
   * @param processId the processId for the KafkaStreams client that should receive this assignment
   * @param assignment the set of tasks to be assigned to this KafkaStreams client
   *
   * @return a new KafkaStreamsAssignment object with the given processId and assignment
   */
  public static KafkaStreamsAssignment of(final ProcessId processId, final Set<AssignedTask> assignment);

  /**
   * This API can be used to request that a followup rebalance be triggered by the KafkaStreams client 
   * receiving this assignment. The followup rebalance will be initiated after the provided deadline
   * has passed, although it will always wait until it has finished the current rebalance before 
   * triggering a new one. This request will last until the new rebalance, and will be erased if a
   * new rebalance begins before the scheduled followup rebalance deadline has elapsed. The next
   * assignment must request the followup rebalance again if it still wants to schedule one for
   * the given instant, otherwise no additional rebalance will be triggered after that.
   * 
   * @param rebalanceDeadline the instant after which this KafkaStreams client will trigger a followup rebalance
   *
   * @return a new KafkaStreamsAssignment object with the same processId and assignment but with the given rebalanceDeadline
   */
  public KafkaStreamsAssignment withFollowupRebalance(final Instant rebalanceDeadline);

  public ProcessID processId();

  public Set<AssignedTask> assignmenttasks();

  /**
   * @return the actual deadline in objective time, after which the followup rebalance will be attempted.
   * Equivalent to {@code 'now + followupRebalanceDelay'}
   */
  public Instant followupRebalanceDeadline();

  public static class AssignedTask {

    public AssignedTask(final TaskId id, final Type taskType);

    enum Type {
        ACTIVE,
        STANDBY
    }
    
    public Type type();

    public TaskId id();
  }
}