scala.collection.immutable

class EmptyMap

[source: scala/collection/immutable/EmptyMap.scala]

@serializable

class EmptyMap[A, +B]
extends Map[A, B]
This class implements empty immutable maps
Author
Martin Oderskty
Version
1.0, 019/01/2007
Method Summary
def - (key : A) : Map[A, B]
Remove a key from this map
def elements : Iterator[(A, B)]
Creates a new iterator over all elements contained in this object.
def empty [C] : Map[A, C]
This method returns a new map instance of the same class mapping keys of the same type to values of type C.
def get (key : A) : Option[B]
Check if this map maps key to a value and return the value if it exists.
def size : Int
Compute the number of key-to-value mappings.
def update [B1 >: B](key : A, value : B1) : Map[A, B1]
This method allows one to create a new map with an additional mapping from key to value. If the map contains already a mapping for key, it will be overridden by this function.
Methods inherited from Map
+, +, ++, ++, -, --, --, withDefault, withDefaultValue, transform, filter, +, incl, incl, excl, excl, mappingToString
Methods inherited from Map
getOrElse, isEmpty, apply, contains, isDefinedAt, keys, keySet, values, equals, hashCode, toString, default, projection, filterKeys, mapElements, stringPrefix
Methods inherited from Collection
toArray
Methods inherited from Iterable
concat, ++, map, flatMap, partition, takeWhile, dropWhile, take, drop, foreach, forall, exists, find, findIndexOf, indexOf, foldLeft, foldRight, /:, :\, reduceLeft, reduceRight, copyToBuffer, sameElements, toList, toStream, mkString, mkString, mkString, addString, addString, copyToArray, hasDefiniteSize
Methods inherited from PartialFunction
orElse, andThen
Methods inherited from Function1
compose
Methods inherited from AnyRef
getClass, clone, notify, notifyAll, wait, wait, wait, finalize, ==, !=, eq, ne, synchronized
Methods inherited from Any
==, !=, isInstanceOf, asInstanceOf
Method Details
def size : Int
Compute the number of key-to-value mappings.
Returns
the number of mappings

def get(key : A) : Option[B]
Check if this map maps key to a value and return the value if it exists.
Parameters
key - the key of the mapping of interest
Returns
the value of the mapping, if it exists

def elements : Iterator[(A, B)]
Creates a new iterator over all elements contained in this object.
Returns
the new iterator

def empty[C] : Map[A, C]
This method returns a new map instance of the same class mapping keys of the same type to values of type C.
Overrides
Map.empty

def update[B1 >: B](key : A, value : B1) : Map[A, B1]
This method allows one to create a new map with an additional mapping from key to value. If the map contains already a mapping for key, it will be overridden by this function.
Parameters
key - ...
value - ...
Returns
the created map
Deprecated
use +({A, B}) instead
Overrides
Map.update

def -(key : A) : Map[A, B]
Remove a key from this map
Parameters
key - the key to be removed
Returns
If the map does not contain a binding for key it is returned unchanged. Otherwise, return a new map without a binding for key
Overrides
Map.-