Class

org.apache.spark

Accumulable

Related Doc: package spark

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class Accumulable[R, T] extends Serializable

A data type that can be accumulated, i.e. has an commutative and associative "add" operation, but where the result type, R, may be different from the element type being added, T.

You must define how to add data, and how to merge two of these together. For some data types, such as a counter, these might be the same operation. In that case, you can use the simpler org.apache.spark.Accumulator. They won't always be the same, though -- e.g., imagine you are accumulating a set. You will add items to the set, and you will union two sets together.

Operations are not thread-safe.

R

the full accumulated data (result type)

T

partial data that can be added in

Annotations
@deprecated
Deprecated

(Since version 2.0.0) use AccumulatorV2

Source
Accumulable.scala
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Serializable, AnyRef, Any
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Instance Constructors

  1. new Accumulable(initialValue: R, param: AccumulableParam[R, T])

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Value Members

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

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    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

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    Definition Classes
    AnyRef → Any
  3. def ++=(term: R): Unit

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    Merge two accumulable objects together

    Merge two accumulable objects together

    Normally, a user will not want to use this version, but will instead call +=.

    term

    the other R that will get merged with this

  4. def +=(term: T): Unit

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    Add more data to this accumulator / accumulable

    Add more data to this accumulator / accumulable

    term

    the data to add

  5. final def ==(arg0: Any): Boolean

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    Definition Classes
    AnyRef → Any
  6. def add(term: T): Unit

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    Add more data to this accumulator / accumulable

    Add more data to this accumulator / accumulable

    term

    the data to add

  7. final def asInstanceOf[T0]: T0

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    Definition Classes
    Any
  8. def clone(): AnyRef

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

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    AnyRef
  10. def equals(arg0: Any): Boolean

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    Definition Classes
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  11. def finalize(): Unit

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    Attributes
    protected[java.lang]
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    @throws( classOf[java.lang.Throwable] )
  12. final def getClass(): Class[_]

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  13. def hashCode(): Int

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  14. val id: Long

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    ID of this accumulator; for internal use only.

  15. final def isInstanceOf[T0]: Boolean

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    Definition Classes
    Any
  16. def localValue: R

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    Get the current value of this accumulator from within a task.

    Get the current value of this accumulator from within a task.

    This is NOT the global value of the accumulator. To get the global value after a completed operation on the dataset, call value.

    The typical use of this method is to directly mutate the local value, eg., to add an element to a Set.

  17. def merge(term: R): Unit

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    Merge two accumulable objects together

    Merge two accumulable objects together

    Normally, a user will not want to use this version, but will instead call add.

    term

    the other R that will get merged with this

  18. val name: Option[String]

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    human-readable name for use in Spark's web UI

  19. final def ne(arg0: AnyRef): Boolean

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

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

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    Definition Classes
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  22. def setValue(newValue: R): Unit

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    Set the accumulator's value.

    Set the accumulator's value. For internal use only.

  23. final def synchronized[T0](arg0: ⇒ T0): T0

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    Definition Classes
    AnyRef
  24. def toString(): String

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    Definition Classes
    Accumulable → AnyRef → Any
  25. def value: R

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    Access the accumulator's current value; only allowed on driver.

  26. def value_=(newValue: R): Unit

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    Set the accumulator's value; only allowed on driver.

  27. final def wait(): Unit

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

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    @throws( ... )
  29. final def wait(arg0: Long): Unit

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    Annotations
    @throws( ... )
  30. val zero: R

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Inherited from Serializable

Inherited from AnyRef

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