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Standard library for the Scala Programming Language
package scala
package collection
package immutable
import java.io.{ObjectInputStream, ObjectOutputStream}
import scala.collection.mutable.Builder
/**
* A generic trait for ordered immutable maps. Concrete classes have to provide
* functionality for the abstract methods in `SeqMap`.
*
* Note that when checking for equality [[SeqMap]] does not take into account
* ordering.
*
* @tparam K the type of the keys contained in this linked map.
* @tparam V the type of the values associated with the keys in this linked map.
*
* @author Matthew de Detrich
* @version 2.13
* @since 2.13
* @define coll immutable seq map
* @define Coll `immutable.SeqMap`
*/
trait SeqMap[K, +V]
extends AbstractMap[K, V]
with MapOps[K, V, SeqMap, SeqMap[K, V]]
object SeqMap extends MapFactory[SeqMap] {
def empty[K, V]: SeqMap[K, V] = EmptyLinkedMap.asInstanceOf[SeqMap[K, V]]
def from[K, V](it: collection.IterableOnce[(K, V)]): SeqMap[K, V] =
it match {
case sm: SeqMap[K, V] => sm
case _ => (newBuilder[K, V] ++= it).result()
}
def newBuilder[K, V]: Builder[(K, V), SeqMap[K, V]] = VectorMap.newBuilder
@SerialVersionUID(3L)
private object EmptyLinkedMap extends SeqMap[Any, Nothing] {
override def size: Int = 0
override def knownSize: Int = 0
override def apply(key: Any) = throw new NoSuchElementException("key not found: " + key)
override def contains(key: Any) = false
def get(key: Any): Option[Nothing] = None
override def getOrElse [V1](key: Any, default: => V1): V1 = default
def iterator: Iterator[(Any, Nothing)] = Iterator.empty
def updated [V1] (key: Any, value: V1): SeqMap[Any, V1] = new SeqMap1(key, value)
def remove(key: Any): SeqMap[Any, Nothing] = this
}
@SerialVersionUID(3L)
private final class SeqMap1[K, +V](key1: K, value1: V) extends SeqMap[K,V] with Serializable {
override def size: Int = 1
override def knownSize: Int = 1
override def apply(key: K) = if (key == key1) value1 else throw new NoSuchElementException("key not found: " + key)
override def contains(key: K) = key == key1
def get(key: K): Option[V] =
if (key == key1) Some(value1) else None
override def getOrElse [V1 >: V](key: K, default: => V1): V1 =
if (key == key1) value1 else default
def iterator = Iterator.single((key1, value1))
def updated[V1 >: V](key: K, value: V1): SeqMap[K, V1] =
if (key == key1) new SeqMap1(key1, value)
else new SeqMap2(key1, value1, key, value)
def remove(key: K): SeqMap[K, V] =
if (key == key1) SeqMap.empty else this
override def foreach[U](f: ((K, V)) => U): Unit = {
f((key1, value1))
}
}
@SerialVersionUID(3L)
private final class SeqMap2[K, +V](key1: K, value1: V, key2: K, value2: V) extends SeqMap[K,V] with Serializable {
override def size: Int = 2
override def knownSize: Int = 2
override def apply(key: K) =
if (key == key1) value1
else if (key == key2) value2
else throw new NoSuchElementException("key not found: " + key)
override def contains(key: K) = (key == key1) || (key == key2)
def get(key: K): Option[V] =
if (key == key1) Some(value1)
else if (key == key2) Some(value2)
else None
override def getOrElse [V1 >: V](key: K, default: => V1): V1 =
if (key == key1) value1
else if (key == key2) value2
else default
def iterator = ((key1, value1) :: (key2, value2) :: Nil).iterator
def updated[V1 >: V](key: K, value: V1): SeqMap[K, V1] =
if (key == key1) new SeqMap2(key1, value, key2, value2)
else if (key == key2) new SeqMap2(key1, value1, key2, value)
else new SeqMap3(key1, value1, key2, value2, key, value)
def remove(key: K): SeqMap[K, V] =
if (key == key1) new SeqMap1(key2, value2)
else if (key == key2) new SeqMap1(key1, value1)
else this
override def foreach[U](f: ((K, V)) => U): Unit = {
f((key1, value1)); f((key2, value2))
}
}
@SerialVersionUID(3L)
private class SeqMap3[K, +V](key1: K, value1: V, key2: K, value2: V, key3: K, value3: V) extends SeqMap[K,V] with Serializable {
override def size: Int = 3
override def knownSize: Int = 3
override def apply(key: K) =
if (key == key1) value1
else if (key == key2) value2
else if (key == key3) value3
else throw new NoSuchElementException("key not found: " + key)
override def contains(key: K) = (key == key1) || (key == key2) || (key == key3)
def get(key: K): Option[V] =
if (key == key1) Some(value1)
else if (key == key2) Some(value2)
else if (key == key3) Some(value3)
else None
override def getOrElse [V1 >: V](key: K, default: => V1): V1 =
if (key == key1) value1
else if (key == key2) value2
else if (key == key3) value3
else default
def iterator = ((key1, value1) :: (key2, value2) :: (key3, value3) :: Nil).iterator
def updated[V1 >: V](key: K, value: V1): SeqMap[K, V1] =
if (key == key1) new SeqMap3(key1, value, key2, value2, key3, value3)
else if (key == key2) new SeqMap3(key1, value1, key2, value, key3, value3)
else if (key == key3) new SeqMap3(key1, value1, key2, value2, key3, value)
else new SeqMap4(key1, value1, key2, value2, key3, value3, key, value)
def remove(key: K): SeqMap[K, V] =
if (key == key1) new SeqMap2(key2, value2, key3, value3)
else if (key == key2) new SeqMap2(key1, value1, key3, value3)
else if (key == key3) new SeqMap2(key1, value1, key2, value2)
else this
override def foreach[U](f: ((K, V)) => U): Unit = {
f((key1, value1)); f((key2, value2)); f((key3, value3))
}
}
@SerialVersionUID(3L)
private final class SeqMap4[K, +V](key1: K, value1: V, key2: K, value2: V, key3: K, value3: V, key4: K, value4: V) extends SeqMap[K,V] with Serializable {
override def size: Int = 4
override def knownSize: Int = 4
override def apply(key: K) =
if (key == key1) value1
else if (key == key2) value2
else if (key == key3) value3
else if (key == key4) value4
else throw new NoSuchElementException("key not found: " + key)
override def contains(key: K) = (key == key1) || (key == key2) || (key == key3) || (key == key4)
def get(key: K): Option[V] =
if (key == key1) Some(value1)
else if (key == key2) Some(value2)
else if (key == key3) Some(value3)
else if (key == key4) Some(value4)
else None
override def getOrElse [V1 >: V](key: K, default: => V1): V1 =
if (key == key1) value1
else if (key == key2) value2
else if (key == key3) value3
else if (key == key4) value4
else default
def iterator = ((key1, value1) :: (key2, value2) :: (key3, value3) :: (key4, value4) :: Nil).iterator
def updated[V1 >: V](key: K, value: V1): SeqMap[K, V1] =
if (key == key1) new SeqMap4(key1, value, key2, value2, key3, value3, key4, value4)
else if (key == key2) new SeqMap4(key1, value1, key2, value, key3, value3, key4, value4)
else if (key == key3) new SeqMap4(key1, value1, key2, value2, key3, value, key4, value4)
else if (key == key4) new SeqMap4(key1, value1, key2, value2, key3, value3, key4, value)
else {
// Directly create the elements for performance reasons
val fields = Vector(key1, key2, key3, key4, key)
val underlying: Map[K, (Int, V1)] = if (useBaseline)
OldHashMap(
(key1, (0, value1)),
(key2, (1, value2)),
(key3, (2, value3)),
(key4, (3, value4)),
(key, (4, value))
)
else
HashMap(
(key1, (0, value1)),
(key2, (1, value2)),
(key3, (2, value3)),
(key4, (3, value4)),
(key, (4, value))
)
new VectorMap(fields, underlying)
}
def remove(key: K): SeqMap[K, V] =
if (key == key1) new SeqMap3(key2, value2, key3, value3, key4, value4)
else if (key == key2) new SeqMap3(key1, value1, key3, value3, key4, value4)
else if (key == key3) new SeqMap3(key1, value1, key2, value2, key4, value4)
else if (key == key4) new SeqMap3(key1, value1, key2, value2, key3, value3)
else this
override def foreach[U](f: ((K, V)) => U): Unit = {
f((key1, value1)); f((key2, value2)); f((key3, value3)); f((key4, value4))
}
}
// getenv not getProperty for Scala.js friendliness.
// TODO remove before 2.13.0-RC1? see scala/collection-strawman#572
private final val useBaseline: Boolean =
System.getenv("SCALA_COLLECTION_IMMUTABLE_USE_BASELINE") == "true"
// scalac generates a `readReplace` method to discard the deserialized state (see https://github.com/scala/bug/issues/10412).
// This prevents it from serializing it in the first place:
private[this] def writeObject(out: ObjectOutputStream): Unit = ()
private[this] def readObject(in: ObjectInputStream): Unit = ()
}