Scala 3/API/scala.collection.mutable/ReusableBuilder

ReusableBuilder

trait ReusableBuilder[-Elem, +To] extends Builder[Elem, To]

ReusableBuilder is a marker trait that indicates that a Builder can be reused to build more than one instance of a collection.

ReusableBuilder is a marker trait that indicates that a Builder can be reused to build more than one instance of a collection. In particular, calling result() followed by clear() will produce a collection and reset the builder to begin building a new collection of the same type.

In general no method other than clear() may be called after result(). It is up to subclasses to implement and to document other allowed sequences of operations (e.g. calling other methods after result() in order to obtain different snapshots of a collection under construction).

Type Params
Elem

the type of elements that get added to the builder.

To

the type of collection that it produced.

trait Builder[Elem, To]
trait Growable[Elem]
trait Clearable
class Object
trait Matchable
class Any
class ofRef[T]
class ofByte
class ofShort
class ofChar
class ofInt
class ofLong
class ofFloat
class ofDouble
class ofBoolean
class ofUnit
class ListBuffer[A]

Value members

Abstract methods

override def clear(): Unit

Clears the contents of this builder.

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

If executed immediately after a call to result(), this allows a new instance of the same type of collection to be built.

Definition Classes
override def result(): To

Produces a collection from the added elements.

Produces a collection from the added elements.

After a call to result, the behavior of all other methods is undefined save for clear(). If clear() is called, then the builder is reset and may be used to build another instance.

Returns

a collection containing the elements added to this builder.

Definition Classes

Inherited methods

final def ++=(xs: IterableOnce[Elem]): ReusableBuilder[Elem, To]

Alias for addAll

Alias for addAll

Inherited from
Growable
final def +=(elem: Elem): ReusableBuilder[Elem, To]

Alias for addOne

Alias for addOne

Inherited from
Growable
def addAll(xs: IterableOnce[Elem]): ReusableBuilder[Elem, To]

Adds all elements produced by an IterableOnce to this growable collection.

Adds all elements produced by an IterableOnce to this growable collection.

Value Params
xs

the IterableOnce producing the elements to add.

Returns

the growable collection itself.

Inherited from
Growable
def addOne(elem: Elem): ReusableBuilder[Elem, To]

Adds a single element to this growable collection.

Adds a single element to this growable collection.

Value Params
elem

the element to add.

Returns

the growable collection itself

Inherited from
Growable
def knownSize: Int
Returns

The number of elements in the collection under construction, if it can be cheaply computed, -1 otherwise. The default implementation always returns -1.

Inherited from
Growable
def mapResult[NewTo](f: To => NewTo): Builder[Elem, NewTo]

A builder resulting from this builder my mapping the result using f.

A builder resulting from this builder my mapping the result using f.

Inherited from
Builder
final def sizeHint(coll: IterableOnce[_], 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.

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 has a known size 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.

Value Params
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.

Inherited from
Builder
def sizeHint(size: Int): Unit

Gives a hint how many elements are expected to be added when the next result is called.

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.

Value Params
size

the hint how many elements will be added.

Inherited from
Builder
final def sizeHintBounded(size: Int, boundingColl: Iterable[_]): 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.

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.

Value Params
boundingColl

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

size

the hint how many elements will be added.

Inherited from
Builder

Deprecated and Inherited methods

@deprecated("Use `++=` aka `addAll` instead of varargs `+=`; infix operations with an operand of multiple args will be deprecated", "2.13.0") @inline
final def +=(elem1: Elem, elem2: Elem, elems: Elem*): ReusableBuilder[Elem, To]

Adds two or more elements to this growable collection.

Adds two or more elements to this growable collection.

Value Params
elem1

the first element to add.

elem2

the second element to add.

elems

the remaining elements to add.

Returns

the growable collection itself

Deprecated
Inherited from
Growable