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Standard library for the Scala Programming Language
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala.collection
/** A trait for all maps upon which operations may be
* implemented in parallel.
*
* @define Coll `GenMap`
* @define coll general map
* @author Martin Odersky
* @author Aleksandar Prokopec
* @since 2.9
* @define mapNote
*
* A map is a collection of bindings from keys to values, where there are
* no duplicate keys.
*/
trait GenMapLike[A, +B, +Repr] extends GenIterableLike[(A, B), Repr] with Equals with Parallelizable[(A, B), parallel.ParMap[A, B]] {
def default(key: A): B
def get(key: A): Option[B]
def apply(key: A): B
def seq: Map[A, B]
def +[B1 >: B](kv: (A, B1)): GenMap[A, B1]
def - (key: A): Repr
// This hash code must be symmetric in the contents but ought not
// collide trivially.
override def hashCode()= scala.util.hashing.MurmurHash3.mapHash(seq)
/** Returns the value associated with a key, or a default value if the key is not contained in the map.
* @param key the key.
* @param default a computation that yields a default value in case no binding for `key` is
* found in the map.
* @tparam B1 the result type of the default computation.
* @return the value associated with `key` if it exists,
* otherwise the result of the `default` computation.
* @usecase def getOrElse(key: A, default: => B): B
* @inheritdoc
*/
def getOrElse[B1 >: B](key: A, default: => B1): B1
/** Tests whether this map contains a binding for a key.
*
* @param key the key
* @return `true` if there is a binding for `key` in this map, `false` otherwise.
*/
def contains(key: A): Boolean
/** Tests whether this map contains a binding for a key. This method,
* which implements an abstract method of trait `PartialFunction`,
* is equivalent to `contains`.
*
* @param key the key
* @return `true` if there is a binding for `key` in this map, `false` otherwise.
*/
def isDefinedAt(key: A): Boolean
def keySet: GenSet[A]
/** Collects all keys of this map in an iterable collection.
*
* @return the keys of this map as an iterable.
*/
def keys: GenIterable[A]
/** Collects all values of this map in an iterable collection.
*
* @return the values of this map as an iterable.
*/
def values: GenIterable[B]
/** Creates an iterator for all keys.
*
* @return an iterator over all keys.
*/
def keysIterator: Iterator[A]
/** Creates an iterator for all values in this map.
*
* @return an iterator over all values that are associated with some key in this map.
*/
def valuesIterator: Iterator[B]
/** Filters this map by retaining only keys satisfying a predicate.
* @param p the predicate used to test keys
* @return an immutable map consisting only of those key value pairs of this map where the key satisfies
* the predicate `p`. The resulting map wraps the original map without copying any elements.
*/
def filterKeys(p: A => Boolean): GenMap[A, B]
/** Transforms this map by applying a function to every retrieved value.
* @param f the function used to transform values of this map.
* @return a map view which maps every key of this map
* to `f(this(key))`. The resulting map wraps the original map without copying any elements.
*/
def mapValues[C](f: B => C): GenMap[A, C]
/** Compares two maps structurally; i.e. checks if all mappings
* contained in this map are also contained in the other map,
* and vice versa.
*
* @param that the other map
* @return `true` if both maps contain exactly the
* same mappings, `false` otherwise.
*/
override def equals(that: Any): Boolean = that match {
case that: GenMap[b, _] =>
(this eq that) ||
(that canEqual this) &&
(this.size == that.size) && {
try {
this forall {
case (k, v) => that.get(k.asInstanceOf[b]) match {
case Some(`v`) =>
true
case _ => false
}
}
} catch {
case ex: ClassCastException =>
println("class cast "); false
}}
case _ =>
false
}
}