org.apache.spark.streaming

StateSpec

sealed abstract class StateSpec[KeyType, ValueType, StateType, MappedType] extends Serializable

:: Experimental :: Abstract class representing all the specifications of the DStream transformation mapWithState operation of a pair DStream (Scala) or a JavaPairDStream (Java). Use the StateSpec.apply() or StateSpec.create() to create instances of this class.

Example in Scala:

// A mapping function that maintains an integer state and return a String
def mappingFunction(key: String, value: Option[Int], state: State[Int]): Option[String] = {
  // Use state.exists(), state.get(), state.update() and state.remove()
  // to manage state, and return the necessary string
}

val spec = StateSpec.function(mappingFunction).numPartitions(10)

val mapWithStateDStream = keyValueDStream.mapWithState[StateType, MappedType](spec)

Example in Java:

// A mapping function that maintains an integer state and return a string
Function3<String, Optional<Integer>, State<Integer>, String> mappingFunction =
    new Function3<String, Optional<Integer>, State<Integer>, String>() {
        @Override
        public Optional<String> call(Optional<Integer> value, State<Integer> state) {
            // Use state.exists(), state.get(), state.update() and state.remove()
            // to manage state, and return the necessary string
        }
    };

 JavaMapWithStateDStream<String, Integer, Integer, String> mapWithStateDStream =
     keyValueDStream.mapWithState(StateSpec.function(mappingFunc));
KeyType

Class of the state key

ValueType

Class of the state value

StateType

Class of the state data

MappedType

Class of the mapped elements

Annotations
@Experimental()
Source
StateSpec.scala
Linear Supertypes
Serializable, Serializable, AnyRef, Any
Ordering
  1. Alphabetic
  2. By inheritance
Inherited
  1. StateSpec
  2. Serializable
  3. Serializable
  4. AnyRef
  5. Any
  1. Hide All
  2. Show all
Learn more about member selection
Visibility
  1. Public
  2. All

Instance Constructors

  1. new StateSpec()

Abstract Value Members

  1. abstract def initialState(javaPairRDD: JavaPairRDD[KeyType, StateType]): StateSpec.this.type

    Set the RDD containing the initial states that will be used by mapWithState

  2. abstract def initialState(rdd: RDD[(KeyType, StateType)]): StateSpec.this.type

    Set the RDD containing the initial states that will be used by mapWithState

  3. abstract def numPartitions(numPartitions: Int): StateSpec.this.type

    Set the number of partitions by which the state RDDs generated by mapWithState will be partitioned.

    Set the number of partitions by which the state RDDs generated by mapWithState will be partitioned. Hash partitioning will be used.

  4. abstract def partitioner(partitioner: Partitioner): StateSpec.this.type

    Set the partitioner by which the state RDDs generated by mapWithState will be be partitioned.

  5. abstract def timeout(idleDuration: Duration): StateSpec.this.type

    Set the duration after which the state of an idle key will be removed.

    Set the duration after which the state of an idle key will be removed. A key and its state is considered idle if it has not received any data for at least the given duration. The mapping function will be called one final time on the idle states that are going to be removed; State.isTimingOut() set to true in that call.

Concrete Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  2. final def !=(arg0: Any): Boolean

    Definition Classes
    Any
  3. final def ##(): Int

    Definition Classes
    AnyRef → Any
  4. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  5. final def ==(arg0: Any): Boolean

    Definition Classes
    Any
  6. final def asInstanceOf[T0]: T0

    Definition Classes
    Any
  7. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  8. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  9. def equals(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any
  10. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  11. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any
  12. def hashCode(): Int

    Definition Classes
    AnyRef → Any
  13. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any
  14. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  15. final def notify(): Unit

    Definition Classes
    AnyRef
  16. final def notifyAll(): Unit

    Definition Classes
    AnyRef
  17. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  18. def toString(): String

    Definition Classes
    AnyRef → Any
  19. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  20. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  21. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

Inherited from Serializable

Inherited from Serializable

Inherited from AnyRef

Inherited from Any

Ungrouped