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Last active December 28, 2018 06:59
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Sample collection implementation with Scala 2.13
package com.tiqwab.example.step4
import scala.collection.mutable.ListBuffer
import scala.collection.{immutable, mutable, SeqFactory, StrictOptimizedLinearSeqOps}
class MyList[+A] private (elems: List[A])
extends immutable.LinearSeq[A] with immutable.LinearSeqOps[A, MyList, MyList[A]]
with StrictOptimizedLinearSeqOps[A, MyList, MyList[A]] {
// To be overridden in implementations, as said in scala.collection.LinearSeq
override def isEmpty: Boolean = elems.isEmpty
override def head: A = elems.head
override def tail: MyList[A] = new MyList(elems.tail)
override def iterator: Iterator[A] = elems.iterator
// To be overridden for LinearSeqOps
override def iterableFactory: SeqFactory[MyList] = MyList
override def toString: String = s"MyList(${elems.mkString(",")})"
object MyList extends SeqFactory[MyList] {
override def from[A](source: IterableOnce[A]): MyList[A] =
override def empty[A]: MyList[A] =
new MyList(List.empty)
override def newBuilder[A]: mutable.Builder[A, MyList[A]] =
new ListBuffer[A].mapResult(elems => new MyList(elems))
package com.tiqwab.example.step4
import scala.collection.mutable.ListBuffer
import scala.collection.{immutable, mutable, MapFactory, StrictOptimizedMapOps}
class MyMap[K, +V] private (elems: Map[K, V])
extends immutable.Map[K, V] with immutable.MapOps[K, V, MyMap, MyMap[K, V]]
with StrictOptimizedMapOps[K, V, MyMap, MyMap[K, V]] {
// Should be implemented for immutable.Map
override def remove(key: K): MyMap[K, V] =
new MyMap(elems.remove(key))
override def updated[V1 >: V](key: K, value: V1): MyMap[K, V1] =
new MyMap(elems.updated(key, value))
override def get(key: K): Option[V] =
override def iterator: Iterator[(K, V)] =
override def mapFactory: MapFactory[MapCC] = MyMap
override def toString: String = s"MyMap(${elems.mkString(",")})"
object MyMap extends MapFactory[MyMap] {
override def from[K, V](it: IterableOnce[(K, V)]): MyMap[K, V] = newBuilder[K, V].addAll(it).result()
override def empty[K, V]: MyMap[K, V] = new MyMap(Map.empty)
override def newBuilder[K, V]: mutable.Builder[(K, V), MyMap[K, V]] =
new ListBuffer[(K, V)]().mapResult(elems => new MyMap(elems.toMap))
package com.tiqwab.example.step4
import scala.collection.mutable.ListBuffer
import scala.collection.{immutable, mutable, IterableFactory, StrictOptimizedSetOps}
class MySet[A] private (elems: Set[A])
extends immutable.Set[A] with immutable.SetOps[A, MySet, MySet[A]] with StrictOptimizedSetOps[A, MySet, MySet[A]] {
// Should be implemented for immutable.Set
override def incl(elem: A): MySet[A] = new MySet(elems.incl(elem))
override def excl(elem: A): MySet[A] = new MySet(elems.excl(elem))
override def contains(elem: A): Boolean = elems.contains(elem)
override def iterator: Iterator[A] = elems.iterator
override def iterableFactory: IterableFactory[MySet] = MySet
override def toString: String = s"MySet(${elems.mkString(",")})"
object MySet extends IterableFactory[MySet] {
override def from[A](source: IterableOnce[A]): MySet[A] = newBuilder[A].addAll(source).result()
override def empty[A]: MySet[A] = new MySet(Set.empty)
override def newBuilder[A]: mutable.Builder[A, MySet[A]] =
new ListBuffer[A]().mapResult(elems => new MySet(elems.toSet))
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