Enum Class KafkaStreams.State

java.lang.Object
java.lang.Enum<KafkaStreams.State>
org.apache.kafka.streams.KafkaStreams.State
All Implemented Interfaces:
Serializable, Comparable<KafkaStreams.State>, Constable
Enclosing class:
KafkaStreams
public static enum KafkaStreams.State extends Enum<KafkaStreams.State>
Kafka Streams states are the possible state that a Kafka Streams instance can be in. An instance must only be in one state at a time. The expected state transition with the following defined states is: 
                +--------------+
        +<----- | Created (0)  |
        |       +-----+--------+
        |             |
        |             v
        |       +----+--+------+
        |       | Re-          |
        +<----- | Balancing (1)| -------->+
        |       +-----+-+------+          |
        |             | ^                 |
        |             v |                 |
        |       +--------------+          v
        |       | Running (2)  | -------->+
        |       +------+-------+          |
        |              |                  |
        |              v                  |
        |       +------+-------+     +----+-------+
        +-----> | Pending      |     | Pending    |
                | Shutdown (3) |     | Error (5)  |
                +------+-------+     +-----+------+
                       |                   |
                       v                   v
                +------+-------+     +-----+--------+
                | Not          |     | Error (6)    |
                | Running (4)  |     +--------------+
                +--------------+
Note the following:
  • RUNNING state will transit to REBALANCING if any of its threads is in PARTITION_REVOKED or PARTITIONS_ASSIGNED state
  • REBALANCING state will transit to RUNNING if all of its threads are in RUNNING state (Note: a thread transits to RUNNING state, if all active tasks got restored are ready for processing. Standby tasks are not considered.)
  • Any state except NOT_RUNNING, PENDING_ERROR or ERROR can go to PENDING_SHUTDOWN (whenever close is called)
  • PENDING_SHUTDOWN and PENDING_ERROR are transitory states where the Streams application gracefully closes its existing resources before transitioning into their corresponding terminal states. These states are not recoverable, and only a restart would get an application back to the RUNNING state.
  • Of special importance: If the global stream thread dies, or all stream threads die (or both) then the instance will be in the ERROR state. The user will not need to close it.

  • Enum Constant Details

  • Method Details

    • values

      public static KafkaStreams.State[] values()
      Returns an array containing the constants of this enum class, in the order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static KafkaStreams.State valueOf(String name)
      Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • hasNotStarted

      public boolean hasNotStarted()

    • isRunningOrRebalancing

      public boolean isRunningOrRebalancing()

    • isShuttingDown

      public boolean isShuttingDown()

    • hasCompletedShutdown

      public boolean hasCompletedShutdown()

    • hasStartedOrFinishedShuttingDown

      public boolean hasStartedOrFinishedShuttingDown()

    • isValidTransition

      public boolean isValidTransition(KafkaStreams.State newState)