Package org.apache.kafka.streams

Enum KafkaStreams.State

java.lang.Object

java.lang.Enum<KafkaStreams.State>

org.apache.kafka.streams.KafkaStreams.State

Enclosing class:

KafkaStreams

public static enum KafkaStreams.State
extends java.lang.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
         |       +--------------+
         +<----- | Running (2)  | -------->+
         |       +----+--+------+          |
         |            |  ^                 |
         |            v  |                 |
         |       +----+--+------+          |
         |       | Re-          |          v
         |       | Balancing (1)| -------->+
         |       +-----+--------+          |
         |             |                   |
         |             v                   v
         |       +-----+--------+     +----+-------+
         +-----> | Pending      |<--- | Error (5)  |
                 | Shutdown (3) |     +------------+
                 +-----+--------+
                       |
                       v
                 +-----+--------+
                 | Not          |
                 | Running (4)  |
                 +--------------+


 

Note the following: - RUNNING state will transit to REBALANCING if any of its threads is in PARTITION_REVOKED state - REBALANCING state will transit to RUNNING if all of its threads are in RUNNING state - Any state except NOT_RUNNING 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 need to close it.

Enum Constant Summary

Enum Constants

Enum Constant	Description
CREATED
ERROR
NOT_RUNNING
PENDING_SHUTDOWN
REBALANCING
RUNNING

Method Summary

Modifier and Type	Method	Description
boolean	isRunning()
boolean	isValidTransition(KafkaStreams.State newState)
static KafkaStreams.State	valueOf(java.lang.String name)	Returns the enum constant of this type with the specified name.
static KafkaStreams.State[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

CREATED

public static final KafkaStreams.State CREATED

REBALANCING

public static final KafkaStreams.State REBALANCING

RUNNING

public static final KafkaStreams.State RUNNING

PENDING_SHUTDOWN

public static final KafkaStreams.State PENDING_SHUTDOWN

NOT_RUNNING

public static final KafkaStreams.State NOT_RUNNING

ERROR

public static final KafkaStreams.State ERROR

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(java.lang.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:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null

isRunning

public boolean isRunning()

isValidTransition

public boolean isValidTransition(KafkaStreams.State newState)