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Trait scala.collection.parallel.Combiner

trait Combiner[-Elem, +To] extends Builder[Elem, To] with Sizing with Parallel

The base trait for all combiners. A combiner incremental collection construction just like a regular builder, but also implements an efficient merge operation of two builders via combine method. Once the collection is constructed, it may be obtained by invoking the result method.

The complexity of the combine method should be less than linear for best performance. The result method doesn't have to be a constant time operation, but may be performed in parallel.

Elem

the type of the elements added to the builder

To

the type of the collection the builder produces

Source
Combiner.scala
Since

2.9

Linear Supertypes
Known Subclasses

Abstract Value Members

abstract def +=(elem: Elem): Combiner.this.type

Adds a single element to the builder.

elem

the element to be added.

returns

the builder itself.

Definition Classes
BuilderGrowable

abstract def clear(): Unit

Clears the contents of this builder. After execution of this method the builder will contain no elements.

Definition Classes
BuilderGrowableClearable

abstract def combine[N <: Elem, NewTo >: To](other: Combiner[N, NewTo]): Combiner[N, NewTo]

Combines the contents of the receiver builder and the other builder, producing a new builder containing both their elements.

This method may combine the two builders by copying them into a larger collection, by producing a lazy view that gets evaluated once result is invoked, or use a merge operation specific to the data structure in question.

Note that both the receiver builder and other builder become invalidated after the invocation of this method, and should be cleared (see clear) if they are to be used again.

Also, combining two combiners c1 and c2 for which c1 eq c2 is true, that is, they are the same objects in memory:

c1.combine(c2)

always does nothing and returns c1.

N

the type of elements contained by the other builder

NewTo

the type of collection produced by the other builder

other

the other builder

returns

the parallel builder containing both the elements of this and the other builder

abstract def result(): To

Produces a collection from the added elements. This is a terminal operation: the builder's contents are undefined after this operation, and no further methods should be called.

returns

a collection containing the elements added to this builder.

Definition Classes
Builder

abstract def size: Int

Definition Classes
Sizing

Concrete Value Members

final def !=(arg0: Any): Boolean

Test two objects for inequality.

returns

true if !(this == that), false otherwise.

Definition Classes
AnyRef → Any

final def ##(): Int

Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

returns

a hash value consistent with ==

Definition Classes
AnyRef → Any

def +(other: String): String

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to any2stringadd[Combiner[Elem, To]] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd

def ++=(xs: TraversableOnce[Elem]): Combiner.this.type

adds all elements produced by a TraversableOnce to this growable collection.

xs

the TraversableOnce producing the elements to add.

returns

the growable collection itself.

Definition Classes
Growable

def +=(elem1: Elem, elem2: Elem, elems: Elem*): Combiner.this.type

adds two or more elements to this growable collection.

elem1

the first element to add.

elem2

the second element to add.

elems

the remaining elements to add.

returns

the growable collection itself

Definition Classes
Growable

def ->[B](y: B): (Combiner[Elem, To], B)

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to ArrowAssoc[Combiner[Elem, To]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()

final def ==(arg0: Any): Boolean

The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

returns

true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any

val _combinerTaskSupport: TaskSupport

Annotations
@transient() @volatile()

final def asInstanceOf[T0]: T0

Cast the receiver object to be of type T0.

Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

returns

the receiver object.

Definition Classes
Any
Exceptions thrown

ClassCastException if the receiver object is not an instance of the erasure of type T0.

def canBeShared: Boolean

Returns true if this combiner has a thread-safe += and is meant to be shared across several threads constructing the collection.

By default, this method returns false.

def clone(): AnyRef

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

returns

a copy of the receiver object.

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( ... ) @native()
Note

not specified by SLS as a member of AnyRef

def combinerTaskSupport: TaskSupport

def combinerTaskSupport_=(cts: TaskSupport): Unit

def ensuring(cond: (Combiner[Elem, To]) ⇒ Boolean, msg: ⇒ Any): Combiner[Elem, To]

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to Ensuring[Combiner[Elem, To]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: (Combiner[Elem, To]) ⇒ Boolean): Combiner[Elem, To]

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to Ensuring[Combiner[Elem, To]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean, msg: ⇒ Any): Combiner[Elem, To]

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to Ensuring[Combiner[Elem, To]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean): Combiner[Elem, To]

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to Ensuring[Combiner[Elem, To]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

final def eq(arg0: AnyRef): Boolean

Tests whether the argument (that) is a reference to the receiver object (this).

The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false. null.eq(null) returns true.

When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

returns

true if the argument is a reference to the receiver object; false otherwise.

Definition Classes
AnyRef

def equals(arg0: Any): Boolean

The equality method for reference types. Default implementation delegates to eq.

See also equals in scala.Any.

returns

true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any

def finalize(): Unit

Called by the garbage collector on the receiver object when there are no more references to the object.

The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
Note

not specified by SLS as a member of AnyRef

def formatted(fmtstr: String): String

Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to StringFormat[Combiner[Elem, To]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

final def getClass(): Class[_]

Returns the runtime class representation of the object.

returns

a class object corresponding to the runtime type of the receiver.

Definition Classes
AnyRef → Any
Annotations
@native()

def hashCode(): Int

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

returns

the hash code value for this object.

Definition Classes
AnyRef → Any
Annotations
@native()

final def isInstanceOf[T0]: Boolean

Test whether the dynamic type of the receiver object is T0.

Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

returns

true if the receiver object is an instance of erasure of type T0; false otherwise.

Definition Classes
Any

def mapResult[NewTo](f: (To) ⇒ NewTo): Builder[Elem, NewTo]

Creates a new builder by applying a transformation function to the results of this builder.

NewTo

the type of collection returned by f.

f

the transformation function.

returns

a new builder which is the same as the current builder except that a transformation function is applied to this builder's result.

Definition Classes
Builder
Note

The original builder should no longer be used after mapResult is called.

final def ne(arg0: AnyRef): Boolean

Equivalent to !(this eq that).

returns

true if the argument is not a reference to the receiver object; false otherwise.

Definition Classes
AnyRef

final def notify(): Unit

Wakes up a single thread that is waiting on the receiver object's monitor.

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

final def notifyAll(): Unit

Wakes up all threads that are waiting on the receiver object's monitor.

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

def resultWithTaskSupport: To

def sizeHint(coll: TraversableLike[_, _], delta: Int): Unit

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

coll

the collection which serves as a hint for the result's size.

delta

a correction to add to the coll.size to produce the size hint.

Definition Classes
Builder

def sizeHint(coll: TraversableLike[_, _]): Unit

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method, which is determined by calling sizeHint.

Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

coll

the collection which serves as a hint for the result's size.

Definition Classes
Builder

def sizeHint(size: Int): Unit

Gives a hint how many elements are expected to be added when the next result is called. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

size

the hint how many elements will be added.

Definition Classes
Builder

def sizeHintBounded(size: Int, boundingColl: TraversableLike[_, _]): Unit

Gives a hint how many elements are expected to be added when the next result is called, together with an upper bound given by the size of some other collection. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

size

the hint how many elements will be added.

boundingColl

the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection's size are reduced.

Definition Classes
Builder

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

Definition Classes
AnyRef

def toParArray: ParArray[T]

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to CollectionsHaveToParArray[Combiner[Elem, To], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (Combiner[Elem, To]) ⇒ GenTraversableOnce[T] is in scope.
Definition Classes
CollectionsHaveToParArray

def toString(): String

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
AnyRef → Any

final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

def [B](y: B): (Combiner[Elem, To], B)

Implicit
This member is added by an implicit conversion from Combiner[Elem, To] to ArrowAssoc[Combiner[Elem, To]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/collection/parallel/Combiner.html