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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2006, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.collection.mutable
//import Predef.UnsupportedOperationException
/** This class represents mutable maps. Concrete map implementations
* just have to provide functionality for the abstract methods in
* <code>scala.collection.Map</code> as well as for <code>update</code>,
* and <code>remove</code>.
*
* @author Matthias Zenger
* @version 1.1, 09/05/2004
*/
[cloneable]
trait Map[A, B] extends AnyRef
with collection.Map[A, B]
with Scriptable[Message[Pair[A, B]]]
{
/** This method allows one to add 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 by this
* function.
*
* @param key
* @param value
*/
def update(key: A, value: B): Unit
/** This method defines syntactic sugar for adding or modifying
* mappings. It is typically used in the following way:
* <pre>
* map += key -> value;
* </pre>
*/
def +=(key: A): MapTo = new MapTo(key)
/** This method adds all the mappings provided by an iterator of
* parameter <code>map</code> to the map.
*
* @param map
*/
def ++=(map: Iterable[Pair[A, B]]): Unit = ++=(map.elements)
/** This method adds all the mappings provided by an iterator of
* parameter <code>map</code> to the map.
*
* @param it
*/
def ++=(it: Iterator[Pair[A, B]]): Unit = it foreach {
case Pair(key, value) => update(key, value)
}
/** <code>incl</code> can be used to add many mappings at the same time
* to the map. The method assumes that a mapping is represented
* by a <code>Pair</code> object who's first component denotes the
* key, and who's second component refers to the value.
*
* @param mappings
*/
def incl(mappings: Pair[A, B]*): Unit = ++=(mappings.elements)
/** This method removes a mapping from the given <code>key</code>.
* If the map does not contain a mapping for the given key, the
* method does nothing.
*
* @param key
*/
def -=(key: A): Unit
/** This method removes all the mappings for keys provided by an
* iterator over the elements of the <code>keys</code> object.
*
* @param keys
*/
def --=(keys: Iterable[A]): Unit = --=(keys.elements)
/** This method removes all the mappings for keys provided by an
* iterator over the elements of the <code>keys</code> object.
*
* @param it
*/
def --=(it: Iterator[A]): Unit = it foreach -=
/** This method will remove all the mappings for the given sequence
* of keys from the map.
*
* @param keys
*/
def excl(keys: A*): Unit = --=(keys.elements)
/** Removes all mappings from the map. After this operation is
* completed, the map is empty.
*/
def clear: Unit = keys foreach -=
/** This function transforms all the values of mappings contained
* in this map with function <code>f</code>.
*
* @param f
*/
def map(f: Pair[A, B] => B): Unit = elements foreach {
case kv @ Pair(key, _) => update(key, f(kv))
}
/** This method removes all the mappings for which the predicate
* <code>p</code> returns <code>false</code>.
*
* @param p
*/
def filter(p: Pair[A, B] => Boolean): Unit = toList foreach {
case kv @ Pair(key, _) => if (!p(kv)) -=(key)
}
/** Send a message to this scriptable object.
*
* @param cmd the message to send.
*/
def <<(cmd: Message[Pair[A, B]]): Unit = cmd match {
case Include(Pair(k, v)) => update(k, v)
case Update(Pair(k, v)) => update(k, v)
case Remove(Pair(k, _)) => this -= k
case Reset() => clear
case s: Script[_] => s.elements foreach <<
case _ => throw new UnsupportedOperationException("message " + cmd + " not understood")
}
/** Return a clone of this map.
*
* @return a map with the same elements.
*/
override def clone(): Map[A, B] = super.clone().asInstanceOf[Map[A, B]]
/** The hashCode method always yields an error, since it is not
* safe to use mutable maps as keys in hash tables.
*
* @return never.
*/
override def hashCode(): Int = throw new UnsupportedOperationException("unsuitable as hash key")
/** Returns a string representation of this map which shows
* all the mappings.
*/
override def toString() =
if (size == 0)
"{}"
else
"{" + {
val iter = elements
var res = mappingToString(iter.next)
while (iter.hasNext) {
res = res + ", " + mappingToString(iter.next)
}
res
} + "}"
/** This method controls how a mapping is represented in the string
* representation provided by method <code>toString</code>.
*
* @param p
*/
def mappingToString(p: Pair[A, B]) = p._1.toString() + " -> " + p._2
class MapTo(key: A) {
def ->(value: B): Unit = update(key, value)
}
}
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