Scala example source code file (GenMapLike.scala)

This example Scala source code file (GenMapLike.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

a, a, b, b, b1, b1, equals, geniterablelike, genmap, genmaplike, map, option, repr, repr

The Scala GenMapLike.scala source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2011, 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() = util.MurmurHash.symmetricHash(seq, Map.hashSeed)
  
  /** 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
  }
}