Package org.apache.kafka.streams

Enum KafkaStreams.State

  • All Implemented Interfaces:
    Serializable, Comparable<KafkaStreams.State>
    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 - Any state except NOT_RUNNING, PENDING_ERROR or ERROR can go to PENDING_SHUTDOWN (whenever close is called) - 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.

    • Method Detail

      • values

        public static KafkaStreams.State[] values()
        Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows: 
        for (KafkaStreams.State c : KafkaStreams.State.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static KafkaStreams.State valueOf​(String name)
        Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (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 type has no constant with the specified name
        NullPointerException - if the argument is null

      • isRunningOrRebalancing

        public boolean isRunningOrRebalancing()