Packages

class ParHashMap[K, +V] extends ParMap[K, V] with GenericParMapTemplate[K, V, ParHashMap] with ParMapLike[K, V, ParHashMap[K, V], HashMap[K, V]] with Serializable

Immutable parallel hash map, based on hash tries.

This is a base trait for Scala parallel collections. It defines behaviour common to all parallel collections. Concrete parallel collections should inherit this trait and ParIterable if they want to define specific combiner factories.

Parallel operations are implemented with divide and conquer style algorithms that parallelize well. The basic idea is to split the collection into smaller parts until they are small enough to be operated on sequentially.

All of the parallel operations are implemented as tasks within this trait. Tasks rely on the concept of splitters, which extend iterators. Every parallel collection defines:

def splitter: IterableSplitter[T]

which returns an instance of IterableSplitter[T], which is a subtype of Splitter[T]. Splitters have a method remaining to check the remaining number of elements, and method split which is defined by splitters. Method split divides the splitters iterate over into disjunct subsets:

def split: Seq[Splitter]

which splits the splitter into a sequence of disjunct subsplitters. This is typically a very fast operation which simply creates wrappers around the receiver collection. This can be repeated recursively.

Tasks are scheduled for execution through a scala.collection.parallel.TaskSupport object, which can be changed through the tasksupport setter of the collection.

Method newCombiner produces a new combiner. Combiners are an extension of builders. They provide a method combine which combines two combiners and returns a combiner containing elements of both combiners. This method can be implemented by aggressively copying all the elements into the new combiner or by lazily binding their results. It is recommended to avoid copying all of the elements for performance reasons, although that cost might be negligible depending on the use case. Standard parallel collection combiners avoid copying when merging results, relying either on a two-step lazy construction or specific data-structure properties.

Methods:

def seq: Sequential
def par: Repr

produce the sequential or parallel implementation of the collection, respectively. Method par just returns a reference to this parallel collection. Method seq is efficient - it will not copy the elements. Instead, it will create a sequential version of the collection using the same underlying data structure. Note that this is not the case for sequential collections in general - they may copy the elements and produce a different underlying data structure.

The combination of methods toMap, toSeq or toSet along with par and seq is a flexible way to change between different collection types.

Since this trait extends the GenIterable trait, methods like size must also be implemented in concrete collections, while iterator forwards to splitter by default.

Each parallel collection is bound to a specific fork/join pool, on which dormant worker threads are kept. The fork/join pool contains other information such as the parallelism level, that is, the number of processors used. When a collection is created, it is assigned the default fork/join pool found in the scala.parallel package object.

Parallel collections are not necessarily ordered in terms of the foreach operation (see Traversable). Parallel sequences have a well defined order for iterators - creating an iterator and traversing the elements linearly will always yield the same order. However, bulk operations such as foreach, map or filter always occur in undefined orders for all parallel collections.

Existing parallel collection implementations provide strict parallel iterators. Strict parallel iterators are aware of the number of elements they have yet to traverse. It's also possible to provide non-strict parallel iterators, which do not know the number of elements remaining. To do this, the new collection implementation must override isStrictSplitterCollection to false. This will make some operations unavailable.

To create a new parallel collection, extend the ParIterable trait, and implement size, splitter, newCombiner and seq. Having an implicit combiner factory requires extending this trait in addition, as well as providing a companion object, as with regular collections.

Method size is implemented as a constant time operation for parallel collections, and parallel collection operations rely on this assumption.

The higher-order functions passed to certain operations may contain side-effects. Since implementations of bulk operations may not be sequential, this means that side-effects may not be predictable and may produce data-races, deadlocks or invalidation of state if care is not taken. It is up to the programmer to either avoid using side-effects or to use some form of synchronization when accessing mutable data.

K

the key type of the map

V

the value type of the map

Self Type
ParHashMap[K, V]
Annotations
@SerialVersionUID()
Source
ParHashMap.scala
Since

2.9

See also

Scala's Parallel Collections Library overview section on Parallel Hash Tries for more information.

Linear Supertypes
Serializable, java.io.Serializable, ParMap[K, V], ParIterable[(K, V)], Immutable, parallel.ParMap[K, V], ParMapLike[K, V, ParHashMap[K, V], HashMap[K, V]], parallel.ParIterable[(K, V)], ParIterableLike[(K, V), ParHashMap[K, V], HashMap[K, V]], Parallel, CustomParallelizable[(K, V), ParHashMap[K, V]], GenericParMapTemplate[K, V, ParHashMap], GenericParTemplate[(K, V), ParIterable], HasNewCombiner[(K, V), ParHashMap[K, V]], GenMap[K, V], GenIterable[(K, V)], GenTraversable[(K, V)], GenericTraversableTemplate[(K, V), ParIterable], HasNewBuilder[(K, V), scala.collection.parallel.immutable.ParIterable[(K, V)] @scala.annotation.unchecked.uncheckedVariance], GenMapLike[K, V, ParHashMap[K, V]], Equals, GenIterableLike[(K, V), ParHashMap[K, V]], GenTraversableLike[(K, V), ParHashMap[K, V]], Parallelizable[(K, V), ParHashMap[K, V]], GenTraversableOnce[(K, V)], AnyRef, Any
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Inherited
  1. ParHashMap
  2. Serializable
  3. Serializable
  4. ParMap
  5. ParIterable
  6. Immutable
  7. ParMap
  8. ParMapLike
  9. ParIterable
  10. ParIterableLike
  11. Parallel
  12. CustomParallelizable
  13. GenericParMapTemplate
  14. GenericParTemplate
  15. HasNewCombiner
  16. GenMap
  17. GenIterable
  18. GenTraversable
  19. GenericTraversableTemplate
  20. HasNewBuilder
  21. GenMapLike
  22. Equals
  23. GenIterableLike
  24. GenTraversableLike
  25. Parallelizable
  26. GenTraversableOnce
  27. AnyRef
  28. Any
Implicitly
  1. by CollectionsHaveToParArray
  2. by any2stringadd
  3. by StringFormat
  4. by Ensuring
  5. by ArrowAssoc
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Instance Constructors

  1. new ParHashMap()

Type Members

  1. trait BuilderOps[Elem, To] extends AnyRef
    Definition Classes
    ParIterableLike
  2. trait SignallingOps[PI <: DelegatedSignalling] extends AnyRef
    Definition Classes
    ParIterableLike
  3. trait TaskOps[R, Tp] extends AnyRef
    Definition Classes
    ParIterableLike
  4. class ParHashMapIterator extends IterableSplitter[(K, V)]
  5. type SSCTask[R, Tp] = StrictSplitterCheckTask[R, Tp]
    Definition Classes
    ParIterableLike

Value Members

  1. def +[U >: V](kv: (K, U)): ParHashMap[K, U]
    Definition Classes
    ParHashMapParMapParMapGenMapLike
  2. def ++[U >: (K, V), That](that: GenTraversableOnce[U])(implicit bf: CanBuildFrom[ParHashMap[K, V], U, That]): That

    Returns a new parallel iterable containing the elements from the left hand operand followed by the elements from the right hand operand.

    Returns a new parallel iterable containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the parallel iterable is the most specific superclass encompassing the element types of the two operands.

    That

    the class of the returned collection. Where possible, That is the same class as the current collection class Repr, but this depends on the element type B being admissible for that class, which means that an implicit instance of type CanBuildFrom[Repr, B, That] is found.

    that

    the traversable to append.

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type B.

    returns

    a new collection of type That which contains all elements of this parallel iterable followed by all elements of that.

    Definition Classes
    ParIterableLikeGenTraversableLike
  3. def -(k: K): ParHashMap[K, V]
    Definition Classes
    ParHashMapGenMapLike
  4. def aggregate[S](z: ⇒ S)(seqop: (S, (K, V)) ⇒ S, combop: (S, S) ⇒ S): S

    Aggregates the results of applying an operator to subsequent elements.

    Aggregates the results of applying an operator to subsequent elements.

    This is a more general form of fold and reduce. It has similar semantics, but does not require the result to be a supertype of the element type. It traverses the elements in different partitions sequentially, using seqop to update the result, and then applies combop to results from different partitions. The implementation of this operation may operate on an arbitrary number of collection partitions, so combop may be invoked arbitrary number of times.

    For example, one might want to process some elements and then produce a Set. In this case, seqop would process an element and append it to the set, while combop would concatenate two sets from different partitions together. The initial value z would be an empty set.

    pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)

    Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).

    S

    the type of accumulated results

    z

    the initial value for the accumulated result of the partition - this will typically be the neutral element for the seqop operator (e.g. Nil for list concatenation or 0 for summation) and may be evaluated more than once

    seqop

    an operator used to accumulate results within a partition

    combop

    an associative operator used to combine results from different partitions

    Definition Classes
    ParIterableLikeGenTraversableOnce
  5. def apply(key: K): V
    Definition Classes
    ParMapLikeGenMapLike
  6. def canEqual(other: Any): Boolean
    Definition Classes
    ParIterableLike
  7. def collect[B](pf: PartialFunction[A, B]): ParHashMap[B]

    [use case] Builds a new collection by applying a partial function to all elements of this immutable parallel hash map on which the function is defined.

    [use case]

    Builds a new collection by applying a partial function to all elements of this immutable parallel hash map on which the function is defined.

    B

    the element type of the returned collection.

    pf

    the partial function which filters and maps the immutable parallel hash map.

    returns

    a new immutable parallel hash map resulting from applying the given partial function pf to each element on which it is defined and collecting the results. The order of the elements is preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

    def collect[S, That](pf: PartialFunction[(K, V), S])(implicit bf: CanBuildFrom[ParHashMap[K, V], S, That]): That

  8. def companion: GenericCompanion[ParIterable] with GenericParCompanion[ParIterable]

    The factory companion object that builds instances of class ParIterable.

    The factory companion object that builds instances of class ParIterable. (or its Iterable superclass where class ParIterable is not a Seq.)

    Definition Classes
    ParIterableParIterableGenericParTemplateGenIterableGenTraversableGenericTraversableTemplate
  9. def contains(key: K): Boolean

    Tests whether this map contains a binding for a key.

    Tests whether this map contains a binding for a key.

    key

    the key

    returns

    true if there is a binding for key in this map, false otherwise.

    Definition Classes
    ParMapLikeGenMapLike
  10. def copyToArray(xs: Array[A], start: Int, len: Int): Unit

    [use case] Copies the elements of this immutable parallel hash map to an array.

    [use case]

    Copies the elements of this immutable parallel hash map to an array. Fills the given array xs with at most len elements of this immutable parallel hash map, starting at position start. Copying will stop once either the end of the current immutable parallel hash map is reached, or the end of the target array is reached, or len elements have been copied.

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    len

    the maximal number of elements to copy.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def copyToArray[U >: (K, V)](xs: Array[U], start: Int, len: Int): Unit

  11. def copyToArray(xs: Array[A], start: Int): Unit

    [use case] Copies the elements of this immutable parallel hash map to an array.

    [use case]

    Copies the elements of this immutable parallel hash map to an array. Fills the given array xs with values of this immutable parallel hash map, beginning at index start. Copying will stop once either the end of the current immutable parallel hash map is reached, or the end of the target array is reached.

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    start

    the starting index.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def copyToArray[U >: (K, V)](xs: Array[U], start: Int): Unit

  12. def copyToArray(xs: Array[A]): Unit

    [use case] Copies the elements of this immutable parallel hash map to an array.

    [use case]

    Copies the elements of this immutable parallel hash map to an array. Fills the given array xs with values of this immutable parallel hash map. Copying will stop once either the end of the current immutable parallel hash map is reached, or the end of the target array is reached.

    Note: will not terminate for infinite-sized collections.

    xs

    the array to fill.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def copyToArray[U >: (K, V)](xs: Array[U]): Unit

  13. def count(p: ((K, V)) ⇒ Boolean): Int

    Counts the number of elements in the parallel iterable which satisfy a predicate.

    Counts the number of elements in the parallel iterable which satisfy a predicate.

    p

    the predicate used to test elements.

    returns

    the number of elements satisfying the predicate p.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  14. def debugBuffer: ArrayBuffer[String]
    Definition Classes
    ParIterableLike
  15. def default(key: K): V
    Definition Classes
    ParMapLikeGenMapLike
  16. def drop(n: Int): ParHashMap[K, V]

    Selects all elements except first n ones.

    Selects all elements except first n ones.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

    the number of elements to drop from this parallel iterable.

    returns

    a parallel iterable consisting of all elements of this parallel iterable except the first n ones, or else the empty parallel iterable, if this parallel iterable has less than n elements. If n is negative, don't drop any elements.

    Definition Classes
    ParIterableLikeGenTraversableLike
  17. def dropWhile(pred: ((K, V)) ⇒ Boolean): ParHashMap[K, V]

    Drops all elements in the longest prefix of elements that satisfy the predicate, and returns a collection composed of the remaining elements.

    Drops all elements in the longest prefix of elements that satisfy the predicate, and returns a collection composed of the remaining elements.

    This method will use indexFlag signalling capabilities. This means that splitters may set and read the indexFlag state. The index flag is initially set to maximum integer value.

    pred

    the predicate used to test the elements

    returns

    a collection composed of all the elements after the longest prefix of elements in this parallel iterable that satisfy the predicate pred

    Definition Classes
    ParIterableLikeGenTraversableLike
  18. def empty: ParHashMap[K, V]
    Definition Classes
    ParHashMapParMapParMapParMapLike
  19. def equals(that: Any): Boolean

    Compares two maps structurally; i.e., checks if all mappings contained in this map are also contained in the other map, and vice versa.

    Compares two maps structurally; i.e., checks if all mappings contained in this map are also contained in the other map, and vice versa.

    that

    the other map

    returns

    true if both maps contain exactly the same mappings, false otherwise.

    Definition Classes
    GenMapLikeEquals → AnyRef → Any
  20. def exists(p: ((K, V)) ⇒ Boolean): Boolean

    Tests whether a predicate holds for some element of this parallel iterable.

    Tests whether a predicate holds for some element of this parallel iterable.

    This method will use abort signalling capabilities. This means that splitters may send and read abort signals.

    p

    a predicate used to test elements

    returns

    true if p holds for some element, false otherwise

    Definition Classes
    ParIterableLikeGenTraversableOnce
  21. def filter(pred: ((K, V)) ⇒ Boolean): ParHashMap[K, V]

    Selects all elements of this parallel iterable which satisfy a predicate.

    Selects all elements of this parallel iterable which satisfy a predicate.

    pred

    the predicate used to test elements.

    returns

    a new parallel iterable consisting of all elements of this parallel iterable that satisfy the given predicate p. Their order may not be preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
  22. def filterKeys(p: (K) ⇒ Boolean): parallel.ParMap[K, V]

    Filters this map by retaining only keys satisfying a predicate.

    Filters this map by retaining only keys satisfying a predicate.

    p

    the predicate used to test keys

    returns

    an immutable map consisting only of those key value pairs of this map where the key satisfies the predicate p. The resulting map wraps the original map without copying any elements.

    Definition Classes
    ParMapLikeGenMapLike
  23. def filterNot(pred: ((K, V)) ⇒ Boolean): ParHashMap[K, V]

    Selects all elements of this parallel iterable which do not satisfy a predicate.

    Selects all elements of this parallel iterable which do not satisfy a predicate.

    pred

    the predicate used to test elements.

    returns

    a new parallel iterable consisting of all elements of this parallel iterable that do not satisfy the given predicate p. Their order may not be preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
  24. def find(p: ((K, V)) ⇒ Boolean): Option[(K, V)]

    Finds some element in the collection for which the predicate holds, if such an element exists.

    Finds some element in the collection for which the predicate holds, if such an element exists. The element may not necessarily be the first such element in the iteration order.

    If there are multiple elements obeying the predicate, the choice is nondeterministic.

    This method will use abort signalling capabilities. This means that splitters may send and read abort signals.

    p

    predicate used to test the elements

    returns

    an option value with the element if such an element exists, or None otherwise

    Definition Classes
    ParIterableLikeGenTraversableOnce
  25. def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): ParHashMap[B]

    [use case] Builds a new collection by applying a function to all elements of this immutable parallel hash map and using the elements of the resulting collections.

    [use case]

    Builds a new collection by applying a function to all elements of this immutable parallel hash map and using the elements of the resulting collections.

    For example:

    def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")

    The type of the resulting collection is guided by the static type of immutable parallel hash map. This might cause unexpected results sometimes. For example:

    // lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
    def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)
    
    // lettersOf will return a Set[Char], not a Seq
    def lettersOf(words: Seq[String]) = words.toSet flatMap (word => word.toSeq)
    
    // xs will be an Iterable[Int]
    val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)
    
    // ys will be a Map[Int, Int]
    val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)
    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new immutable parallel hash map resulting from applying the given collection-valued function f to each element of this immutable parallel hash map and concatenating the results.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

    def flatMap[S, That](f: ((K, V)) ⇒ GenTraversableOnce[S])(implicit bf: CanBuildFrom[ParHashMap[K, V], S, That]): That

  26. def flatten[B]: ParHashMap[B]

    [use case] Converts this immutable parallel hash map of traversable collections into a immutable parallel hash map formed by the elements of these traversable collections.

    [use case]

    Converts this immutable parallel hash map of traversable collections into a immutable parallel hash map formed by the elements of these traversable collections.

    The resulting collection's type will be guided by the static type of immutable parallel hash map. For example:

    val xs = List(
               Set(1, 2, 3),
               Set(1, 2, 3)
             ).flatten
    // xs == List(1, 2, 3, 1, 2, 3)
    
    val ys = Set(
               List(1, 2, 3),
               List(3, 2, 1)
             ).flatten
    // ys == Set(1, 2, 3)
    B

    the type of the elements of each traversable collection.

    returns

    a new immutable parallel hash map resulting from concatenating all element immutable parallel hash maps.

    Definition Classes
    GenericTraversableTemplate
    Full Signature

    def flatten[B](implicit asTraversable: ((K, V)) ⇒ GenTraversableOnce[B]): ParIterable[B]

  27. def fold[U >: (K, V)](z: U)(op: (U, U) ⇒ U): U

    Folds the elements of this sequence using the specified associative binary operator.

    Folds the elements of this sequence using the specified associative binary operator. The order in which the elements are reduced is unspecified and may be nondeterministic.

    Note this method has a different signature than the foldLeft and foldRight methods of the trait Traversable. The result of folding may only be a supertype of this parallel collection's type parameter T.

    U

    a type parameter for the binary operator, a supertype of T.

    z

    a neutral element for the fold operation, it may be added to the result an arbitrary number of times, not changing the result (e.g. Nil for list concatenation, 0 for addition, or 1 for multiplication)

    op

    a binary operator that must be associative

    returns

    the result of applying fold operator op between all the elements and z

    Definition Classes
    ParIterableLikeGenTraversableOnce
  28. def foldLeft[S](z: S)(op: (S, (K, V)) ⇒ S): S

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going left to right with the start value z on the left:

    op(...op(z, x_1), x_2, ..., x_n)

    where x1, ..., xn are the elements of this parallel iterable. Returns z if this parallel iterable is empty.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  29. def foldRight[S](z: S)(op: ((K, V), S) ⇒ S): S

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going right to left with the start value z on the right:

    op(x_1, op(x_2, ... op(x_n, z)...))

    where x1, ..., xn are the elements of this parallel iterable. Returns z if this parallel iterable is empty.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  30. def forall(p: ((K, V)) ⇒ Boolean): Boolean

    Tests whether a predicate holds for all elements of this parallel iterable.

    Tests whether a predicate holds for all elements of this parallel iterable.

    This method will use abort signalling capabilities. This means that splitters may send and read abort signals.

    p

    a predicate used to test elements

    returns

    true if p holds for all elements, false otherwise

    Definition Classes
    ParIterableLikeGenTraversableOnce
  31. def foreach[U](f: ((K, V)) ⇒ U): Unit

    Applies a function f to all the elements of parallel iterable in an undefined order.

    Applies a function f to all the elements of parallel iterable in an undefined order.

    U

    the result type of the function applied to each element, which is always discarded

    f

    function applied to each element

    Definition Classes
    ParIterableLikeGenTraversableLikeGenTraversableOnce
  32. def genericBuilder[B]: Combiner[B, ParIterable[B]]

    The generic builder that builds instances of Traversable at arbitrary element types.

    The generic builder that builds instances of Traversable at arbitrary element types.

    Definition Classes
    GenericParTemplateGenericTraversableTemplate
  33. def genericCombiner[B]: Combiner[B, ParIterable[B]]
    Definition Classes
    GenericParTemplate
  34. def genericMapCombiner[P, Q]: Combiner[(P, Q), ParHashMap[P, Q]]
    Definition Classes
    GenericParMapTemplate
  35. def get(k: K): Option[V]
    Definition Classes
    ParHashMapGenMapLike
  36. def getOrElse(key: K, default: ⇒ V): V

    [use case] Returns the value associated with a key, or a default value if the key is not contained in the map.

    [use case]

    Returns the value associated with a key, or a default value if the key is not contained in the map.

    key

    the key.

    default

    a computation that yields a default value in case no binding for key is found in the map.

    returns

    the value associated with key if it exists, otherwise the result of the default computation.

    Definition Classes
    ParMapLikeGenMapLike
    Full Signature

    def getOrElse[U >: V](key: K, default: ⇒ U): U

  37. def groupBy[K](f: ((K, V)) ⇒ K): ParMap[K, ParHashMap[K, V]]

    Partitions this parallel iterable into a map of parallel iterables according to some discriminator function.

    Partitions this parallel iterable into a map of parallel iterables according to some discriminator function.

    Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new parallel iterable.

    K

    the type of keys returned by the discriminator function.

    f

    the discriminator function.

    returns

    A map from keys to parallel iterables such that the following invariant holds:

    (xs groupBy f)(k) = xs filter (x => f(x) == k)

    That is, every key k is bound to a parallel iterable of those elements x for which f(x) equals k.

    Definition Classes
    ParIterableLikeGenTraversableLike
  38. def hasDefiniteSize: Boolean

    Tests whether this parallel iterable is known to have a finite size.

    Tests whether this parallel iterable is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as Stream, the predicate returns true if all elements have been computed. It returns false if the stream is not yet evaluated to the end. Non-empty Iterators usually return false even if they were created from a collection with a known finite size.

    Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that hasDefiniteSize returns true. However, checking hasDefiniteSize can provide an assurance that size is well-defined and non-termination is not a concern.

    returns

    true if this collection is known to have finite size, false otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  39. def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

    the hash code value for this object.

    Definition Classes
    GenMapLike → AnyRef → Any
  40. def head: (K, V)

    Selects the first element of this parallel iterable.

    Selects the first element of this parallel iterable.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    the first element of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    NoSuchElementException if the parallel iterable is empty.

  41. def headOption: Option[(K, V)]

    Optionally selects the first element.

    Optionally selects the first element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    the first element of this parallel iterable if it is nonempty, None if it is empty.

    Definition Classes
    ParIterableLikeGenTraversableLike
  42. def init: ParHashMap[K, V]

    Selects all elements except the last.

    Selects all elements except the last.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    a parallel iterable consisting of all elements of this parallel iterable except the last one.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    UnsupportedOperationException if the parallel iterable is empty.

  43. def isDefinedAt(key: K): Boolean

    Tests whether this map contains a binding for a key.

    Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait PartialFunction, is equivalent to contains.

    key

    the key

    returns

    true if there is a binding for key in this map, false otherwise.

    Definition Classes
    ParMapLikeGenMapLike
  44. def isEmpty: Boolean

    Tests whether the parallel iterable is empty.

    Tests whether the parallel iterable is empty.

    Note: Implementations in subclasses that are not repeatedly traversable must take care not to consume any elements when isEmpty is called.

    returns

    true if the parallel iterable contains no elements, false otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  45. def isStrictSplitterCollection: Boolean

    Denotes whether this parallel collection has strict splitters.

    Denotes whether this parallel collection has strict splitters.

    This is true in general, and specific collection instances may choose to override this method. Such collections will fail to execute methods which rely on splitters being strict, i.e. returning a correct value in the remaining method.

    This method helps ensure that such failures occur on method invocations, rather than later on and in unpredictable ways.

    Definition Classes
    ParIterableLike
  46. final def isTraversableAgain: Boolean

    Tests whether this parallel iterable can be repeatedly traversed.

    Tests whether this parallel iterable can be repeatedly traversed.

    returns

    true

    Definition Classes
    ParIterableLikeGenTraversableLikeGenTraversableOnce
  47. def iterator: Splitter[(K, V)]

    Creates a new split iterator used to traverse the elements of this collection.

    Creates a new split iterator used to traverse the elements of this collection.

    By default, this method is implemented in terms of the protected splitter method.

    returns

    a split iterator

    Definition Classes
    ParIterableLikeGenIterableLike
  48. def keySet: parallel.ParSet[K]
    Definition Classes
    ParMapLikeGenMapLike
  49. def keys: parallel.ParIterable[K]

    Collects all keys of this map in an iterable collection.

    Collects all keys of this map in an iterable collection.

    returns

    the keys of this map as an iterable.

    Definition Classes
    ParMapLikeGenMapLike
  50. def keysIterator: IterableSplitter[K]

    Creates an iterator for all keys.

    Creates an iterator for all keys.

    returns

    an iterator over all keys.

    Definition Classes
    ParMapLikeGenMapLike
  51. def last: (K, V)

    Selects the last element.

    Selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    The last element of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    NoSuchElementException If the parallel iterable is empty.

  52. def lastOption: Option[(K, V)]

    Optionally selects the last element.

    Optionally selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    the last element of this parallel iterable$ if it is nonempty, None if it is empty.

    Definition Classes
    ParIterableLikeGenTraversableLike
  53. def map[B](f: (A) ⇒ B): ParHashMap[B]

    [use case] Builds a new collection by applying a function to all elements of this immutable parallel hash map.

    [use case]

    Builds a new collection by applying a function to all elements of this immutable parallel hash map.

    B

    the element type of the returned collection.

    f

    the function to apply to each element.

    returns

    a new immutable parallel hash map resulting from applying the given function f to each element of this immutable parallel hash map and collecting the results.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

    def map[S, That](f: ((K, V)) ⇒ S)(implicit bf: CanBuildFrom[ParHashMap[K, V], S, That]): That

  54. def mapCompanion: GenericParMapCompanion[ParHashMap]
    Definition Classes
    ParHashMapParMapParMapGenericParMapTemplate
  55. def mapValues[S](f: (V) ⇒ S): parallel.ParMap[K, S]

    Transforms this map by applying a function to every retrieved value.

    Transforms this map by applying a function to every retrieved value.

    f

    the function used to transform values of this map.

    returns

    a map view which maps every key of this map to f(this(key)). The resulting map wraps the original map without copying any elements.

    Definition Classes
    ParMapLikeGenMapLike
  56. def max: A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

    the largest element of this immutable parallel hash map.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def max[U >: (K, V)](implicit ord: Ordering[U]): (K, V)

    Exceptions thrown

    UnsupportedOperationException if this immutable parallel hash map is empty.

  57. def maxBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the largest value measured by function f.

    [use case]

    Finds the first element which yields the largest value measured by function f.

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this immutable parallel hash map with the largest value measured by function f.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def maxBy[S](f: ((K, V)) ⇒ S)(implicit cmp: Ordering[S]): (K, V)

    Exceptions thrown

    UnsupportedOperationException if this immutable parallel hash map is empty.

  58. def min: A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

    the smallest element of this immutable parallel hash map

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def min[U >: (K, V)](implicit ord: Ordering[U]): (K, V)

    Exceptions thrown

    UnsupportedOperationException if this immutable parallel hash map is empty.

  59. def minBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the smallest value measured by function f.

    [use case]

    Finds the first element which yields the smallest value measured by function f.

    B

    The result type of the function f.

    f

    The measuring function.

    returns

    the first element of this immutable parallel hash map with the smallest value measured by function f.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def minBy[S](f: ((K, V)) ⇒ S)(implicit cmp: Ordering[S]): (K, V)

    Exceptions thrown

    UnsupportedOperationException if this immutable parallel hash map is empty.

  60. def mkString: String

    Displays all elements of this parallel iterable in a string.

    Displays all elements of this parallel iterable in a string.

    returns

    a string representation of this parallel iterable. In the resulting string the string representations (w.r.t. the method toString) of all elements of this parallel iterable follow each other without any separator string.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  61. def mkString(sep: String): String

    Displays all elements of this parallel iterable in a string using a separator string.

    Displays all elements of this parallel iterable in a string using a separator string.

    sep

    the separator string.

    returns

    a string representation of this parallel iterable. In the resulting string the string representations (w.r.t. the method toString) of all elements of this parallel iterable are separated by the string sep.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Example:
    1. List(1, 2, 3).mkString("|") = "1|2|3"

  62. def mkString(start: String, sep: String, end: String): String

    Displays all elements of this parallel iterable in a string using start, end, and separator strings.

    Displays all elements of this parallel iterable in a string using start, end, and separator strings.

    start

    the starting string.

    sep

    the separator string.

    end

    the ending string.

    returns

    a string representation of this parallel iterable. The resulting string begins with the string start and ends with the string end. Inside, the string representations (w.r.t. the method toString) of all elements of this parallel iterable are separated by the string sep.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Example:
    1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"

  63. def nonEmpty: Boolean

    Tests whether the parallel iterable is not empty.

    Tests whether the parallel iterable is not empty.

    returns

    true if the parallel iterable contains at least one element, false otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  64. def par: ParHashMap[K, V]

    Returns a parallel implementation of this collection.

    Returns a parallel implementation of this collection.

    For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, par takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.

    Specific collections (e.g. ParArray or mutable.ParHashMap) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, par takes constant or sublinear time.

    All parallel collections return a reference to themselves.

    returns

    a parallel implementation of this collection

    Definition Classes
    ParIterableLikeCustomParallelizableParallelizable
  65. def partition(pred: ((K, V)) ⇒ Boolean): (ParHashMap[K, V], ParHashMap[K, V])

    Partitions this parallel iterable in two parallel iterables according to a predicate.

    Partitions this parallel iterable in two parallel iterables according to a predicate.

    pred

    the predicate on which to partition.

    returns

    a pair of parallel iterables: the first parallel iterable consists of all elements that satisfy the predicate p and the second parallel iterable consists of all elements that don't. The relative order of the elements in the resulting parallel iterables may not be preserved.

    Definition Classes
    ParIterableLikeGenTraversableLike
  66. def product: A

    [use case] Multiplies up the elements of this collection.

    [use case]

    Multiplies up the elements of this collection.

    returns

    the product of all elements in this immutable parallel hash map of numbers of type Int. Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the immutable parallel hash map and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def product[U >: (K, V)](implicit num: Numeric[U]): U

  67. def reduce[U >: (K, V)](op: (U, U) ⇒ U): U

    Reduces the elements of this sequence using the specified associative binary operator.

    Reduces the elements of this sequence using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    Note this method has a different signature than the reduceLeft and reduceRight methods of the trait Traversable. The result of reducing may only be a supertype of this parallel collection's type parameter T.

    U

    A type parameter for the binary operator, a supertype of T.

    op

    A binary operator that must be associative.

    returns

    The result of applying reduce operator op between all the elements if the collection is nonempty.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  68. def reduceLeft[U >: (K, V)](op: (U, (K, V)) ⇒ U): U
    Definition Classes
    ParIterableLike
  69. def reduceLeftOption[U >: (K, V)](op: (U, (K, V)) ⇒ U): Option[U]

    Optionally applies a binary operator to all elements of this parallel iterable, going left to right.

    Optionally applies a binary operator to all elements of this parallel iterable, going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    op

    the binary operator.

    returns

    an option value containing the result of reduceLeft(op) if this parallel iterable is nonempty, None otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  70. def reduceOption[U >: (K, V)](op: (U, U) ⇒ U): Option[U]

    Optionally reduces the elements of this sequence using the specified associative binary operator.

    Optionally reduces the elements of this sequence using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    Note this method has a different signature than the reduceLeftOption and reduceRightOption methods of the trait Traversable. The result of reducing may only be a supertype of this parallel collection's type parameter T.

    U

    A type parameter for the binary operator, a supertype of T.

    op

    A binary operator that must be associative.

    returns

    An option value containing result of applying reduce operator op between all the elements if the collection is nonempty, and None otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  71. def reduceRight[U >: (K, V)](op: ((K, V), U) ⇒ U): U

    Applies a binary operator to all elements of this parallel iterable, going right to left.

    Applies a binary operator to all elements of this parallel iterable, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going right to left:

    op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))

    where x1, ..., xn are the elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Exceptions thrown

    UnsupportedOperationException if this parallel iterable is empty.

  72. def reduceRightOption[U >: (K, V)](op: ((K, V), U) ⇒ U): Option[U]

    Optionally applies a binary operator to all elements of this parallel iterable, going right to left.

    Optionally applies a binary operator to all elements of this parallel iterable, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    op

    the binary operator.

    returns

    an option value containing the result of reduceRight(op) if this parallel iterable is nonempty, None otherwise.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  73. def repr: ParHashMap[K, V]
    Definition Classes
    ParIterableLikeGenTraversableLike
  74. def sameElements(that: GenIterable[A]): Boolean

    [use case] Checks if the other iterable collection contains the same elements in the same order as this immutable parallel hash map.

    [use case]

    Checks if the other iterable collection contains the same elements in the same order as this immutable parallel hash map.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    Note: will not terminate for infinite-sized collections.

    that

    the collection to compare with.

    returns

    true, if both collections contain the same elements in the same order, false otherwise.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

    def sameElements[U >: (K, V)](that: GenIterable[U]): Boolean

  75. def scan(z: (K, V))(op: ((K, V), (K, V)) ⇒ (K, V)): ParHashMap[(K, V)]

    [use case] Computes a prefix scan of the elements of the collection.

    [use case]

    Computes a prefix scan of the elements of the collection.

    Note: The neutral element z may be applied more than once.

    z

    neutral element for the operator op

    op

    the associative operator for the scan

    returns

    a new immutable parallel hash map containing the prefix scan of the elements in this immutable parallel hash map

    Definition Classes
    ParIterableLikeGenTraversableLike
    Full Signature

    def scan[U >: (K, V), That](z: U)(op: (U, U) ⇒ U)(implicit bf: CanBuildFrom[ParHashMap[K, V], U, That]): That

  76. def scanLeft[S, That](z: S)(op: (S, (K, V)) ⇒ S)(implicit bf: CanBuildFrom[ParHashMap[K, V], S, That]): That

    Produces a collection containing cumulative results of applying the operator going left to right.

    Produces a collection containing cumulative results of applying the operator going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    That

    the actual type of the resulting collection

    z

    the initial value

    op

    the binary operator applied to the intermediate result and the element

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    ParIterableLikeGenTraversableLike
  77. def scanRight[S, That](z: S)(op: ((K, V), S) ⇒ S)(implicit bf: CanBuildFrom[ParHashMap[K, V], S, That]): That

    Produces a collection containing cumulative results of applying the operator going right to left.

    Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    Example:

    List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)
    That

    the actual type of the resulting collection

    z

    the initial value

    op

    the binary operator applied to the intermediate result and the element

    bf

    an implicit value of class CanBuildFrom which determines the result class That from the current representation type Repr and the new element type B.

    returns

    collection with intermediate results

    Definition Classes
    ParIterableLikeGenTraversableLike
  78. def seq: HashMap[K, V]
  79. def size: Int

    The size of this immutable parallel hash map.

    The size of this immutable parallel hash map.

    Note: will not terminate for infinite-sized collections.

    returns

    the number of elements in this immutable parallel hash map.

    Definition Classes
    ParHashMapGenTraversableLikeGenTraversableOnce
  80. def slice(unc_from: Int, unc_until: Int): ParHashMap[K, V]

    Selects an interval of elements.

    Selects an interval of elements. The returned collection is made up of all elements x which satisfy the invariant:

    from <= indexOf(x) < until

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    unc_from

    the lowest index to include from this parallel iterable.

    unc_until

    the lowest index to EXCLUDE from this parallel iterable.

    returns

    a parallel iterable containing the elements greater than or equal to index from extending up to (but not including) index until of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
  81. def span(pred: ((K, V)) ⇒ Boolean): (ParHashMap[K, V], ParHashMap[K, V])

    Splits this parallel iterable into a prefix/suffix pair according to a predicate.

    Splits this parallel iterable into a prefix/suffix pair according to a predicate.

    This method will use indexFlag signalling capabilities. This means that splitters may set and read the indexFlag state. The index flag is initially set to maximum integer value.

    pred

    the predicate used to test the elements

    returns

    a pair consisting of the longest prefix of the collection for which all the elements satisfy pred, and the rest of the collection

    Definition Classes
    ParIterableLikeGenTraversableLike
  82. def splitAt(n: Int): (ParHashMap[K, V], ParHashMap[K, V])

    Splits this parallel iterable into two at a given position.

    Splits this parallel iterable into two at a given position. Note: c splitAt n is equivalent to (but possibly more efficient than) (c take n, c drop n).

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

    the position at which to split.

    returns

    a pair of parallel iterables consisting of the first n elements of this parallel iterable, and the other elements.

    Definition Classes
    ParIterableLikeGenTraversableLike
  83. def splitter: IterableSplitter[(K, V)]

    Creates a new parallel iterator used to traverse the elements of this parallel collection.

    Creates a new parallel iterator used to traverse the elements of this parallel collection. This iterator is more specific than the iterator of the returned by iterator, and augmented with additional accessor and transformer methods.

    returns

    a parallel iterator

    Definition Classes
    ParHashMapParIterableLike
  84. def stringPrefix: String

    Defines the prefix of this object's toString representation.

    Defines the prefix of this object's toString representation.

    returns

    a string representation which starts the result of toString applied to this parallel map . By default the string prefix is the simple name of the collection class parallel map .

    Definition Classes
    ParMapParMapParIterableGenTraversableLike
  85. def sum: A

    [use case] Sums up the elements of this collection.

    [use case]

    Sums up the elements of this collection.

    returns

    the sum of all elements in this immutable parallel hash map of numbers of type Int. Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the immutable parallel hash map and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def sum[U >: (K, V)](implicit num: Numeric[U]): U

  86. def tail: ParHashMap[K, V]

    Selects all elements except the first.

    Selects all elements except the first.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    a parallel iterable consisting of all elements of this parallel iterable except the first one.

    Definition Classes
    ParIterableLikeGenTraversableLike
    Exceptions thrown

    UnsupportedOperationException if the parallel iterable is empty.

  87. def take(n: Int): ParHashMap[K, V]

    Selects first n elements.

    Selects first n elements.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

    the number of elements to take from this parallel iterable.

    returns

    a parallel iterable consisting only of the first n elements of this parallel iterable, or else the whole parallel iterable, if it has less than n elements. If n is negative, returns an empty parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableLike
  88. def takeWhile(pred: ((K, V)) ⇒ Boolean): ParHashMap[K, V]

    Takes the longest prefix of elements that satisfy the predicate.

    Takes the longest prefix of elements that satisfy the predicate.

    This method will use indexFlag signalling capabilities. This means that splitters may set and read the indexFlag state. The index flag is initially set to maximum integer value.

    pred

    the predicate used to test the elements

    returns

    the longest prefix of this parallel iterable of elements that satisfy the predicate pred

    Definition Classes
    ParIterableLikeGenTraversableLike
  89. def tasksupport: TaskSupport

    The task support object which is responsible for scheduling and load-balancing tasks to processors.

    The task support object which is responsible for scheduling and load-balancing tasks to processors.

    Definition Classes
    ParIterableLike
    See also

    scala.collection.parallel.TaskSupport

  90. def tasksupport_=(ts: TaskSupport): Unit

    Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.

    Changes the task support object which is responsible for scheduling and load-balancing tasks to processors.

    A task support object can be changed in a parallel collection after it has been created, but only during a quiescent period, i.e. while there are no concurrent invocations to parallel collection methods.

    Here is a way to change the task support of a parallel collection:

    import scala.collection.parallel._
    val pc = mutable.ParArray(1, 2, 3)
    pc.tasksupport = new ForkJoinTaskSupport(
      new java.util.concurrent.ForkJoinPool(2))
    Definition Classes
    ParIterableLike
    See also

    scala.collection.parallel.TaskSupport

  91. def to[Col[_]]: Col[A]

    [use case] Converts this immutable parallel hash map into another by copying all elements.

    [use case]

    Converts this immutable parallel hash map into another by copying all elements.

    Note: will not terminate for infinite-sized collections.

    Col

    The collection type to build.

    returns

    a new collection containing all elements of this immutable parallel hash map.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def to[Col[_]](implicit cbf: CanBuildFrom[Nothing, (K, V), Col[(K, V)]]): Col[(K, V)]

  92. def toArray: Array[A]

    [use case] Converts this immutable parallel hash map to an array.

    [use case]

    Converts this immutable parallel hash map to an array.

    Note: will not terminate for infinite-sized collections.

    returns

    an array containing all elements of this immutable parallel hash map. An ClassTag must be available for the element type of this immutable parallel hash map.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Full Signature

    def toArray[U >: (K, V)](implicit arg0: ClassTag[U]): Array[U]

  93. def toBuffer[U >: (K, V)]: Buffer[U]

    Uses the contents of this parallel iterable to create a new mutable buffer.

    Uses the contents of this parallel iterable to create a new mutable buffer.

    Note: will not terminate for infinite-sized collections.

    returns

    a buffer containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  94. def toIndexedSeq: immutable.IndexedSeq[(K, V)]

    Converts this parallel iterable to an indexed sequence.

    Converts this parallel iterable to an indexed sequence.

    Note: will not terminate for infinite-sized collections.

    returns

    an indexed sequence containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  95. def toIterable: ParIterable[(K, V)]

    Converts this parallel iterable to an iterable collection.

    Converts this parallel iterable to an iterable collection. Note that the choice of target Iterable is lazy in this default implementation as this TraversableOnce may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterable containing all elements of this parallel iterable.

    Definition Classes
    ParIterableParIterableLikeGenTraversableOnce
  96. def toIterator: scala.Iterator[(K, V)]

    Returns an Iterator over the elements in this parallel iterable.

    Returns an Iterator over the elements in this parallel iterable. Will return the same Iterator if this instance is already an Iterator.

    Note: will not terminate for infinite-sized collections.

    returns

    an Iterator containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  97. def toList: List[(K, V)]

    Converts this parallel iterable to a list.

    Converts this parallel iterable to a list.

    Note: will not terminate for infinite-sized collections.

    returns

    a list containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  98. def toMap[T, U]: collection.Map[T, U]

    [use case] Converts this immutable parallel hash map to a map.

    [use case]

    Converts this immutable parallel hash map to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.

    Note: will not terminate for infinite-sized collections.

    returns

    a map of type immutable.Map[T, U] containing all key/value pairs of type (T, U) of this immutable parallel hash map.

    Definition Classes
    ParMapParIterableLikeGenTraversableOnce
    Full Signature

    def toMap[P, Q](implicit ev: <:<[(K, V), (P, Q)]): ParMap[P, Q]

  99. def toParArray: ParArray[T]
    Implicit
    This member is added by an implicit conversion from ParHashMap[K, V] to CollectionsHaveToParArray[ParHashMap[K, V], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (ParHashMap[K, V]) ⇒ GenTraversableOnce[T] is in scope.
    Definition Classes
    CollectionsHaveToParArray
  100. def toSeq: ParSeq[(K, V)]

    Converts this parallel iterable to a sequence.

    Converts this parallel iterable to a sequence. As with toIterable, it's lazy in this default implementation, as this TraversableOnce may be lazy and unevaluated.

    Note: will not terminate for infinite-sized collections.

    returns

    a sequence containing all elements of this parallel iterable.

    Definition Classes
    ParIterableParIterableLikeGenTraversableOnce
  101. def toSet[U >: (K, V)]: ParSet[U]

    Converts this parallel iterable to a set.

    Converts this parallel iterable to a set.

    Note: will not terminate for infinite-sized collections.

    returns

    a set containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  102. def toStream: Stream[(K, V)]

    Converts this parallel iterable to a stream.

    Converts this parallel iterable to a stream.

    returns

    a stream containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  103. def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

    a String representation of the object.

    Definition Classes
    ParIterableLike → AnyRef → Any
  104. def toTraversable: GenTraversable[(K, V)]

    Converts this parallel iterable to an unspecified Traversable.

    Converts this parallel iterable to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

    Note: will not terminate for infinite-sized collections.

    returns

    a Traversable containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  105. def toVector: Vector[(K, V)]

    Converts this parallel iterable to a Vector.

    Converts this parallel iterable to a Vector.

    Note: will not terminate for infinite-sized collections.

    returns

    a vector containing all elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
  106. def transpose[B](implicit asTraversable: ((K, V)) ⇒ GenTraversableOnce[B]): ParIterable[ParIterable[B]]

    Transposes this collection of traversable collections into a collection of collections.

    Transposes this collection of traversable collections into a collection of collections.

    The resulting collection's type will be guided by the static type of collection. For example:

    val xs = List(
               Set(1, 2, 3),
               Set(4, 5, 6)).transpose
    // xs == List(
    //         List(1, 4),
    //         List(2, 5),
    //         List(3, 6))
    
    val ys = Vector(
               List(1, 2, 3),
               List(4, 5, 6)).transpose
    // ys == Vector(
    //         Vector(1, 4),
    //         Vector(2, 5),
    //         Vector(3, 6))
    B

    the type of the elements of each traversable collection.

    asTraversable

    an implicit conversion which asserts that the element type of this collection is a Traversable.

    returns

    a two-dimensional collection of collections which has as nth row the nth column of this collection.

    Definition Classes
    GenericTraversableTemplate
    Annotations
    @migration
    Migration

    (Changed in version 2.9.0) transpose throws an IllegalArgumentException if collections are not uniformly sized.

    Exceptions thrown

    IllegalArgumentException if all collections in this collection are not of the same size.

  107. def unzip[A1, A2](implicit asPair: ((K, V)) ⇒ (A1, A2)): (ParIterable[A1], ParIterable[A2])

    Converts this collection of pairs into two collections of the first and second half of each pair.

    Converts this collection of pairs into two collections of the first and second half of each pair.

    val xs = Traversable(
               (1, "one"),
               (2, "two"),
               (3, "three")).unzip
    // xs == (Traversable(1, 2, 3),
    //        Traversable(one, two, three))
    A1

    the type of the first half of the element pairs

    A2

    the type of the second half of the element pairs

    asPair

    an implicit conversion which asserts that the element type of this collection is a pair.

    returns

    a pair of collections, containing the first, respectively second half of each element pair of this collection.

    Definition Classes
    GenericTraversableTemplate
  108. def unzip3[A1, A2, A3](implicit asTriple: ((K, V)) ⇒ (A1, A2, A3)): (ParIterable[A1], ParIterable[A2], ParIterable[A3])

    Converts this collection of triples into three collections of the first, second, and third element of each triple.

    Converts this collection of triples into three collections of the first, second, and third element of each triple.

    val xs = Traversable(
               (1, "one", '1'),
               (2, "two", '2'),
               (3, "three", '3')).unzip3
    // xs == (Traversable(1, 2, 3),
    //        Traversable(one, two, three),
    //        Traversable(1, 2, 3))
    A1

    the type of the first member of the element triples

    A2

    the type of the second member of the element triples

    A3

    the type of the third member of the element triples

    asTriple

    an implicit conversion which asserts that the element type of this collection is a triple.

    returns

    a triple of collections, containing the first, second, respectively third member of each element triple of this collection.

    Definition Classes
    GenericTraversableTemplate
  109. def updated[U >: V](key: K, value: U): ParMap[K, U]
    Definition Classes
    ParMapParMapGenMap
  110. def values: parallel.ParIterable[V]

    Collects all values of this map in an iterable collection.

    Collects all values of this map in an iterable collection.

    returns

    the values of this map as an iterable.

    Definition Classes
    ParMapLikeGenMapLike
  111. def valuesIterator: IterableSplitter[V]

    Creates an iterator for all values in this map.

    Creates an iterator for all values in this map.

    returns

    an iterator over all values that are associated with some key in this map.

    Definition Classes
    ParMapLikeGenMapLike
  112. def withDefault[U >: V](d: (K) ⇒ U): ParMap[K, U]

    The same map with a given default function.

    The same map with a given default function. Note: get, contains, iterator, keys, etc are not affected by withDefault.

    Invoking transformer methods (e.g. map) will not preserve the default value.

    d

    the function mapping keys to values, used for non-present keys

    returns

    a wrapper of the map with a default value

    Definition Classes
    ParMap
  113. def withDefaultValue[U >: V](d: U): ParMap[K, U]

    The same map with a given default value.

    The same map with a given default value.

    Invoking transformer methods (e.g. map) will not preserve the default value.

    d

    default value used for non-present keys

    returns

    a wrapper of the map with a default value

    Definition Classes
    ParMap
  114. def withFilter(pred: ((K, V)) ⇒ Boolean): ParHashMap[K, V]
    Definition Classes
    ParIterableLike
  115. def zip[B](that: GenIterable[B]): ParHashMap[(A, B)]

    [use case] Returns a immutable parallel hash map formed from this immutable parallel hash map and another iterable collection by combining corresponding elements in pairs.

    [use case]

    Returns a immutable parallel hash map formed from this immutable parallel hash map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    B

    the type of the second half of the returned pairs

    that

    The iterable providing the second half of each result pair

    returns

    a new immutable parallel hash map containing pairs consisting of corresponding elements of this immutable parallel hash map and that. The length of the returned collection is the minimum of the lengths of this immutable parallel hash map and that.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

    def zip[U >: (K, V), S, That](that: GenIterable[S])(implicit bf: CanBuildFrom[ParHashMap[K, V], (U, S), That]): That

  116. def zipAll[B](that: Iterable[B], thisElem: A, thatElem: B): ParHashMap[(A, B)]

    [use case] Returns a immutable parallel hash map formed from this immutable parallel hash map and another iterable collection by combining corresponding elements in pairs.

    [use case]

    Returns a immutable parallel hash map formed from this immutable parallel hash map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    B

    the type of the second half of the returned pairs

    that

    The iterable providing the second half of each result pair

    thisElem

    the element to be used to fill up the result if this immutable parallel hash map is shorter than that.

    thatElem

    the element to be used to fill up the result if that is shorter than this immutable parallel hash map.

    returns

    a new immutable parallel hash map containing pairs consisting of corresponding elements of this immutable parallel hash map and that. The length of the returned collection is the maximum of the lengths of this immutable parallel hash map and that. If this immutable parallel hash map is shorter than that, thisElem values are used to pad the result. If that is shorter than this immutable parallel hash map, thatElem values are used to pad the result.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

    def zipAll[S, U >: (K, V), That](that: GenIterable[S], thisElem: U, thatElem: S)(implicit bf: CanBuildFrom[ParHashMap[K, V], (U, S), That]): That

  117. def zipWithIndex: ParHashMap[(A, Int)]

    [use case] Zips this immutable parallel hash map with its indices.

    [use case]

    Zips this immutable parallel hash map with its indices.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

    A new immutable parallel hash map containing pairs consisting of all elements of this immutable parallel hash map paired with their index. Indices start at 0.

    Definition Classes
    ParIterableLikeGenIterableLike
    Full Signature

    def zipWithIndex[U >: (K, V), That](implicit bf: CanBuildFrom[ParHashMap[K, V], (U, Int), That]): That

    Example:
    1. List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))

Deprecated Value Members

  1. def /:[S](z: S)(op: (S, (K, V)) ⇒ S): S

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Applies a binary operator to a start value and all elements of this parallel iterable, going left to right.

    Note: /: is alternate syntax for foldLeft; z /: xs is the same as xs foldLeft z.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = (5 /: a)(_+_)
    b: Int = 15
    
    scala> val c = (5 /: a)((x,y) => x + y)
    c: Int = 15

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    z

    the start value.

    op

    the binary operator.

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going left to right with the start value z on the left:

    op(...op(op(z, x_1), x_2), ..., x_n)

    where x1, ..., xn are the elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldLeft instead of /:

  2. def :\[S](z: S)(op: ((K, V), S) ⇒ S): S

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Applies a binary operator to all elements of this parallel iterable and a start value, going right to left.

    Note: :\ is alternate syntax for foldRight; xs :\ z is the same as xs foldRight z.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

    scala> val a = List(1,2,3,4)
    a: List[Int] = List(1, 2, 3, 4)
    
    scala> val b = (a :\ 5)(_+_)
    b: Int = 15
    
    scala> val c = (a :\ 5)((x,y) => x + y)
    c: Int = 15
    z

    the start value

    op

    the binary operator

    returns

    the result of inserting op between consecutive elements of this parallel iterable, going right to left with the start value z on the right:

    op(x_1, op(x_2, ... op(x_n, z)...))

    where x1, ..., xn are the elements of this parallel iterable.

    Definition Classes
    ParIterableLikeGenTraversableOnce
    Annotations
    @deprecated
    Deprecated

    (Since version 2.12.10) Use foldRight instead of :\

  3. def view: IterableView[(K, V), HashMap[K, V]]
    Definition Classes
    ParIterableLike
    Annotations
    @deprecated
    Deprecated

    (Since version 2.11.0) use .seq.view instead