spark

Accumulable

class Accumulable[R, T] extends Serializable

A datatype 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 datatypes, such as a counter, these might be the same operation. In that case, you can use the simpler 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.

R

the full accumulated data (result type)

T

partial data that can be added in

Linear Supertypes
Serializable, AnyRef, Any
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  1. Accumulable
  2. Serializable
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Instance Constructors

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

    initialValue

    initial value of accumulator

    param

    helper object defining how to add elements of type R and T

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. def ++=(term: R): Unit

    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 Accumulable that will get merged with this

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

    Add more data to this accumulator / accumulable

    Add more data to this accumulator / accumulable

    term

    the data to add

  6. final def ==(arg0: AnyRef): Boolean

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

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

    Definition Classes
    Any
  9. def clone(): AnyRef

    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws()
  10. var deserialized: Boolean

  11. final def eq(arg0: AnyRef): Boolean

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

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

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

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

    Definition Classes
    AnyRef → Any
  16. val id: Long

  17. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any
  18. def localValue: R

    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.

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

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

    Definition Classes
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  21. final def notifyAll(): Unit

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

    Definition Classes
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  23. def toString(): String

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

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

  25. def value_=(r: R): Unit

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

  26. final def wait(): Unit

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

    Definition Classes
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    @throws()
  28. final def wait(arg0: Long): Unit

    Definition Classes
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    @throws()
  29. val zero: R

Inherited from Serializable

Inherited from AnyRef

Inherited from Any