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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2010, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection
package mutable
import generic._
/** <p>
* A generic template for mutable maps from keys of type <code>A</code> to
* values of type <code>B</code>.
* </p>
* <p>
* To implement a concrete mutable map, you need to provide implementations
* of the following methods:
* </p><pre>
* <b>def</b> get(key: A): Option[B]
* <b>def</b> iterator: Iterator[(A, B)]
* <b>def</b> += (kv: (A, B)): <b>this.type</b>
* <b>def</b> -= (key: A): <b>this.type</b></pre>
* <p>
* If you wish that methods <code>like</code>, <code>take</code>,
* <code>drop</code>, <code>filter</code> return the same kind of map, you
* should also override:
* </p><pre>
* <b>def</b> empty: This</pre>
* <p>
* If you to avoid the unncessary construction of an <code>Option</code>
* object, you could also override <code>apply</code>, <code>update</code>,
* and <code>delete</code>.
* </p>
* <p>
* It is also good idea to override methods <code>foreach</code> and
* <code>size</code> for efficiency.
* </p>
*
* @since 2.8
*/
trait MapLike[A, B, +This <: MapLike[A, B, This] with Map[A, B]]
extends MapLikeBase[A, B, This]
with Builder[(A, B), This]
with Growable[(A, B)]
with Shrinkable[A]
with Cloneable[This]
{ self =>
import scala.collection.Traversable
/** <p>
* A common implementation of <code>newBuilder</code> for all mutable maps
* in terms of <code>empty</code>.
* </p>
* <p>
* Overrides <code>MapLike</code> implementation for better efficiency.
* </p>
*/
override protected[this] def newBuilder: Builder[(A, B), This] = empty
/** Adds a new mapping from <code>key</code>
* to <code>value</code> to the map. If the map already contains a
* mapping for <code>key</code>, it will be overridden.
*
* @param key The key to update
* @param value The new value
*/
def put(key: A, value: B): Option[B] = {
val r = get(key)
update(key, value)
r
}
/** Adds a new mapping from <code>key</code>
* to <code>value</code> to the map. If the map already contains a
* mapping for <code>key</code>, it will be overridden.
*
* @param key The key to update
* @param value The new value
* @return An option consisting of value associated previously associated with `key` in the map,
* or None if `key` was not yet defined in the map.
*/
def update(key: A, value: B) { this += ((key, value)) }
/** Add a new key/value mapping this map.
* @param kv the key/value pair.
* @return the map itself
*/
def += (kv: (A, B)): this.type
/** Create a new map consisting of all elements of the current map
* plus the given mapping from <code>key</code> to <code>value</code>.
*
* @param key The key to ad
* @param value The new value
* @return A fresh immutable map
*/
override def updated[B1 >: B](key: A, value: B1): mutable.Map[A, B1] = this + ((key, value))
/** Add a new key/value mapping and return the map itself.
*
* @param kv the key/value mapping to be added
*/
@deprecated("This operation will create a new map in the future. To add an element as a side\n"+
"effect to an existing map and return that map itself, use +=. If you do want\n"+
"to create a fresh map, you can use `clone() +=' to avoid a @deprecated warning.")
def + (kv: (A, B)): this.type = { update(kv._1, kv._2); this }
/** Adds two or more key/value mappings and return the map itself.
* with the added elements.
*
* @param elem1 the first element to add.
* @param elem2 the second element to add.
* @param elems the remaining elements to add.
*/
@deprecated("This operation will create a new map in the future. To add an element as a side\n"+
"effect to an existing map and return that map itself, use +=. If you do want to\n"+
"create a fresh map, you can use `clone() +=` to avoid a @deprecated warning.")
def +(elem1: (A, B), elem2: (A, B), elems: (A, B)*): this.type =
this += elem1 += elem2 ++= elems
/** Adds a number of elements provided by a traversable object
* via its <code>iterator</code> method and returns
* either the collection itself (if it is mutable), or a new collection
* with the added elements.
*
* @param iter the traversable object.
*/
@deprecated("This operation will create a new map in the future. To add elements as a side\n"+
"effect to an existing map and return that map itself, use ++=. If you do want\n"+
"to create a fresh map, you can use `clone() ++=` to avoid a @deprecated warning.")
def ++(iter: Traversable[(A, B)]): this.type = { for (elem <- iter) +=(elem); this }
/** Adds a number of elements provided by an iterator
* via its <code>iterator</code> method and returns
* the collection itself.
*
* @param iter the iterator
*/
@deprecated("This operation will create a new map in the future. To add elements as a side\n"+
"effect to an existing map and return that map itself, use ++=. If you do want\n"+
"to create a fresh map, you can use `clone() +=` to avoid a @deprecated warning.")
def ++(iter: Iterator[(A, B)]): this.type = { for (elem <- iter) +=(elem); this }
/** If given key is defined in this map, remove it and return associated value as an Option.
* If key is not present return None.
* @param key the key to be removed
*/
def remove(key: A): Option[B] = {
val r = get(key)
this -= key
r
}
/** Delete a key from this map if it is present.
* @param key the key to be removed
* @note same as `delete`.
*/
def -= (key: A): this.type
/** Delete a key from this map if it is present and return the map itself.
* @param key the key to be removed
*/
@deprecated("This operation will create a new map in the future. To add elements as a side\n"+
"effect to an existing map and return that map itself, use -=. If you do want\n"+
"to create a fresh map, you can use `clone() -=` to avoid a @deprecated warning.")
override def -(key: A): This = { -=(key); repr }
/** If given key is defined in this map, remove it and return associated value as an Option.
* If key is not present return None.
* @param key the key to be removed
*/
@deprecated("Use `remove' instead") def removeKey(key: A): Option[B] = remove(key)
/** Removes all elements from the set. After this operation is completed,
* the set will be empty.
*/
def clear() { for ((k, v) <- this.iterator) -=(k) }
/** If given key is already in this map, returns associated value
* Otherwise, computes value from given expression `op`, stores with key
* in map and returns that value.
*/
def getOrElseUpdate(key: A, op: => B): B =
get(key) match {
case Some(v) => v
case None => val d = op; this(key) = d; d
}
/** This function transforms all the values of mappings contained
* in this map with function <code>f</code>.
*
* @param f The transformation to apply
*/
def transform(f: (A, B) => B): this.type = {
this.iterator foreach {
case (key, value) => update(key, f(key, value))
}
this
}
/** Retain only those mappings for which the predicate
* <code>p</code> returns <code>true</code>.
*
* @param p The test predicate
*/
@deprecated("cannot be type inferred because of retain in Iterable.")
def retain(p: (A, B) => Boolean): this.type = {
for ((k, v) <- this) if (!p(k, v)) -=(k)
this
}
override def clone(): This =
empty ++= repr
/** The result when this map is used as a builder */
def result: This = repr
/** Removes two or more elements from this collection and returns
* the collection itself.
*
* @param elem1 the first element to remove.
* @param elem2 the second element to remove.
* @param elems the remaining elements to remove.
*/
@deprecated("Use -= instead if you intend to remove by side effect from an existing collection.\n"+
"Use `clone() -=' if you intend to create a new collection.")
override def -(elem1: A, elem2: A, elems: A*): This = {
this -= elem1 -= elem2 --= elems
repr
}
/** Removes a number of elements provided by a Traversable object and returns
* the collection itself.
*
* @param iter the Traversable object.
*/
@deprecated("Use --= instead if you intend to remove by side effect from an existing collection.\n"+
"Use `clone() --=' if you intend to create a new collection.")
override def --(iter: Traversable[A]): This = {
for (elem <- iter) -=(elem)
repr
}
/** Removes a number of elements provided by an iterator and returns
* the collection itself.
*
* @param iter the iterator
*/
@deprecated("Use --= instead if you intend to remove by side effect from an existing collection.\n"+
"Use `clone() --=' if you intend to create a new collection.")
override def --(iter: Iterator[A]): This = {
for (elem <- iter) -=(elem)
repr
}
}
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