Scala example source code file (DecorateAsJava.scala)

This example Scala source code file (DecorateAsJava.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

asjava, asjavacollection, asjavadictionary, asjavaenumeration, b, decorateasjava, iterable, iterator, map, seq

The DecorateAsJava.scala Scala example source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2006-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://www.scala-lang.org/           **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala
package collection
package convert

import java.{ lang => jl, util => ju }, java.util.{ concurrent => juc }
import Decorators._
import WrapAsJava._
import scala.language.implicitConversions


/** A collection of decorators that allow to convert between
 *  Scala and Java collections using `asScala` and `asJava` methods.
 *
 *  The following conversions are supported via `asJava`, `asScala`
 *
 *  - `scala.collection.Iterable` <=> `java.lang.Iterable`
 *  - `scala.collection.Iterator` <=> `java.util.Iterator`
 *  - `scala.collection.mutable.Buffer` <=> `java.util.List`
 *  - `scala.collection.mutable.Set` <=> `java.util.Set`
 *  - `scala.collection.mutable.Map` <=> `java.util.Map`
 *  - `scala.collection.mutable.concurrent.Map` <=> `java.util.concurrent.ConcurrentMap`
 *
 *  In all cases, converting from a source type to a target type and back
 *  again will return the original source object, e.g.
 *  {{{
 *    import scala.collection.JavaConverters._
 *
 *    val sl = new scala.collection.mutable.ListBuffer[Int]
 *    val jl : java.util.List[Int] = sl.asJava
 *    val sl2 : scala.collection.mutable.Buffer[Int] = jl.asScala
 *    assert(sl eq sl2)
 *  }}}
 *  The following conversions also are supported, but the
 *  direction Scala to Java is done my a more specifically named method:
 *  `asJavaCollection`, `asJavaEnumeration`, `asJavaDictionary`.
 *
 *  - `scala.collection.Iterable` <=> `java.util.Collection`
 *  - `scala.collection.Iterator` <=> `java.util.Enumeration`
 *  - `scala.collection.mutable.Map` <=> `java.util.Dictionary`
 *
 *  In addition, the following one way conversions are provided via `asJava`:
 *
 *  - `scala.collection.Seq` => `java.util.List`
 *  - `scala.collection.mutable.Seq` => `java.util.List`
 *  - `scala.collection.Set` => `java.util.Set`
 *  - `scala.collection.Map` => `java.util.Map`
 *
 *  @author Martin Odersky
 *  @since  2.8.1
 */

trait DecorateAsJava {
  /**
   * Adds an `asJava` method that implicitly converts a Scala `Iterator` to a
   * Java `Iterator`. The returned Java `Iterator` is backed by the provided Scala
   * `Iterator` and any side-effects of using it via the Java interface will
   * be visible via the Scala interface and vice versa.
   *
   * If the Scala `Iterator` was previously obtained from an implicit or explicit
   * call of `asIterator(java.util.Iterator)` then the original Java `Iterator`
   * will be returned by the `asJava` method.
   *
   * @param i The `Iterator` to be converted.
   * @return An object with an `asJava` method that returns a Java `Iterator` view of the argument.
   */
  implicit def asJavaIteratorConverter[A](i : Iterator[A]): AsJava[ju.Iterator[A]] =
    new AsJava(asJavaIterator(i))

  /**
   * Adds an `asJavaEnumeration` method that implicitly converts a Scala
   * `Iterator` to a Java `Enumeration`. The returned Java `Enumeration` is
   * backed by the provided Scala `Iterator` and any side-effects of using
   * it via the Java interface will be visible via the Scala interface and
   * vice versa.
   *
   * If the Scala `Iterator` was previously obtained from an implicit or
   * explicit call of `asIterator(java.util.Enumeration)` then the
   * original Java `Enumeration` will be returned.
   *
   * @param i The `Iterator` to be converted.
   * @return An object with an `asJavaEnumeration` method that returns a Java
   *         `Enumeration` view of the argument.
   */
  implicit def asJavaEnumerationConverter[A](i : Iterator[A]): AsJavaEnumeration[A] =
    new AsJavaEnumeration(i)

  /**
   * Adds an `asJava` method that implicitly converts a Scala `Iterable` to
   * a Java `Iterable`.
   *
   * The returned Java `Iterable` is backed by the provided Scala `Iterable`
   * and any side-effects of using it via the Java interface will be visible
   * via the Scala interface and vice versa.
   *
   * If the Scala `Iterable` was previously obtained from an implicit or
   * explicit call of `asIterable(java.lang.Iterable)` then the original
   * Java `Iterable` will be returned.
   *
   * @param i The `Iterable` to be converted.
   * @return An object with an `asJavaCollection` method that returns a Java
   *         `Iterable` view of the argument.
   */
  implicit def asJavaIterableConverter[A](i : Iterable[A]): AsJava[jl.Iterable[A]] =
    new AsJava(asJavaIterable(i))

  /**
   * Adds an `asJavaCollection` method that implicitly converts a Scala
   * `Iterable` to an immutable Java `Collection`.
   *
   * If the Scala `Iterable` was previously obtained from an implicit or
   * explicit call of `asSizedIterable(java.util.Collection)` then the
   * original Java `Collection` will be returned.
   *
   * @param i The `SizedIterable` to be converted.
   * @return An object with an `asJava` method that returns a Java
   *         `Collection` view of the argument.
   */
  implicit def asJavaCollectionConverter[A](i : Iterable[A]): AsJavaCollection[A] =
    new AsJavaCollection(i)

  /**
   * Adds an `asJava` method that implicitly converts a Scala mutable `Buffer`
   * to a Java `List`.
   *
   * The returned Java `List` is backed by the provided Scala `Buffer` and any
   * side-effects of using it via the Java interface will be visible via the
   * Scala interface and vice versa.
   *
   * If the Scala `Buffer` was previously obtained from an implicit or explicit
   * call of `asBuffer(java.util.List)` then the original Java `List` will be
   * returned.
   *
   * @param b The `Buffer` to be converted.
   * @return An object with an `asJava` method that returns a Java `List` view
   *         of the argument.
   */
  implicit def bufferAsJavaListConverter[A](b : mutable.Buffer[A]): AsJava[ju.List[A]] =
    new AsJava(bufferAsJavaList(b))

  /**
   * Adds an `asJava` method that implicitly converts a Scala mutable `Seq`
   * to a Java `List`.
   *
   * The returned Java `List` is backed by the provided Scala `Seq` and any
   * side-effects of using it via the Java interface will be visible via the
   * Scala interface and vice versa.
   *
   * If the Scala `Seq` was previously obtained from an implicit or explicit
   * call of `asSeq(java.util.List)` then the original Java `List` will be
   * returned.
   *
   * @param b The `Seq` to be converted.
   * @return An object with an `asJava` method that returns a Java `List`
   *         view of the argument.
   */
  implicit def mutableSeqAsJavaListConverter[A](b : mutable.Seq[A]): AsJava[ju.List[A]] =
    new AsJava(mutableSeqAsJavaList(b))

  /**
   * Adds an `asJava` method that implicitly converts a Scala `Seq` to a
   * Java `List`.
   *
   * The returned Java `List` is backed by the provided Scala `Seq` and any
   * side-effects of using it via the Java interface will be visible via the
   * Scala interface and vice versa.
   *
   * If the Scala `Seq` was previously obtained from an implicit or explicit
   * call of `asSeq(java.util.List)` then the original Java `List` will be
   * returned.
   *
   * @param b The `Seq` to be converted.
   * @return An object with an `asJava` method that returns a Java `List`
   *         view of the argument.
   */
  implicit def seqAsJavaListConverter[A](b : Seq[A]): AsJava[ju.List[A]] =
    new AsJava(seqAsJavaList(b))

  /**
   * Adds an `asJava` method that implicitly converts a Scala mutable `Set`>
   * to a Java `Set`.
   *
   * The returned Java `Set` is backed by the provided Scala `Set` and any
   * side-effects of using it via the Java interface will be visible via
   * the Scala interface and vice versa.
   *
   * If the Scala `Set` was previously obtained from an implicit or explicit
   * call of `asSet(java.util.Set)` then the original Java `Set` will be
   * returned.
   *
   * @param s The `Set` to be converted.
   * @return An object with an `asJava` method that returns a Java `Set` view
   *         of the argument.
   */
  implicit def mutableSetAsJavaSetConverter[A](s : mutable.Set[A]): AsJava[ju.Set[A]] =
    new AsJava(mutableSetAsJavaSet(s))

  /**
   * Adds an `asJava` method that implicitly converts a Scala `Set` to a
   * Java `Set`.
   *
   * The returned Java `Set` is backed by the provided Scala `Set` and any
   * side-effects of using it via the Java interface will be visible via
   * the Scala interface and vice versa.
   *
   * If the Scala `Set` was previously obtained from an implicit or explicit
   * call of `asSet(java.util.Set)` then the original Java `Set` will be
   * returned.
   *
   * @param s The `Set` to be converted.
   * @return An object with an `asJava` method that returns a Java `Set` view
   *         of the argument.
   */
  implicit def setAsJavaSetConverter[A](s : Set[A]): AsJava[ju.Set[A]] =
    new AsJava(setAsJavaSet(s))

  /**
   * Adds an `asJava` method that implicitly converts a Scala mutable `Map`
   * to a Java `Map`.
   *
   * The returned Java `Map` is backed by the provided Scala `Map` and any
   * side-effects of using it via the Java interface will be visible via the
   * Scala interface and vice versa.
   *
   * If the Scala `Map` was previously obtained from an implicit or explicit
   * call of `asMap(java.util.Map)` then the original Java `Map` will be
   * returned.
   *
   * @param m The `Map` to be converted.
   * @return An object with an `asJava` method that returns a Java `Map` view
   *         of the argument.
   */
  implicit def mutableMapAsJavaMapConverter[A, B](m : mutable.Map[A, B]): AsJava[ju.Map[A, B]] =
    new AsJava(mutableMapAsJavaMap(m))

  /**
   * Adds an `asJavaDictionary` method that implicitly converts a Scala
   * mutable `Map` to a Java `Dictionary`.
   *
   * The returned Java `Dictionary` is backed by the provided Scala
   * `Dictionary` and any side-effects of using it via the Java interface
   * will be visible via the Scala interface and vice versa.
   *
   * If the Scala `Dictionary` was previously obtained from an implicit or
   * explicit call of `asMap(java.util.Dictionary)` then the original
   * Java `Dictionary` will be returned.
   *
   * @param m The `Map` to be converted.
   * @return An object with an `asJavaDictionary` method that returns a
   *         Java `Dictionary` view of the argument.
   */
  implicit def asJavaDictionaryConverter[A, B](m : mutable.Map[A, B]): AsJavaDictionary[A, B] =
    new AsJavaDictionary(m)

  /**
   * Adds an `asJava` method that implicitly converts a Scala `Map` to
   * a Java `Map`.
   *
   * The returned Java `Map` is backed by the provided Scala `Map` and any
   * side-effects of using it via the Java interface will be visible via
   * the Scala interface and vice versa.
   *
   * If the Scala `Map` was previously obtained from an implicit or explicit
   * call of `asMap(java.util.Map)` then the original Java `Map` will be
   * returned.
   *
   * @param m The `Map` to be converted.
   * @return An object with an `asJava` method that returns a Java `Map` view
   *         of the argument.
   */
  implicit def mapAsJavaMapConverter[A, B](m : Map[A, B]): AsJava[ju.Map[A, B]] =
    new AsJava(mapAsJavaMap(m))

  /**
   * Adds an `asJava` method that implicitly converts a Scala mutable
   * `concurrent.Map` to a Java `ConcurrentMap`.
   *
   * The returned Java `ConcurrentMap` is backed by the provided Scala
   * `concurrent.Map` and any side-effects of using it via the Java interface
   * will be visible via the Scala interface and vice versa.
   *
   * If the Scala `concurrent.Map` was previously obtained from an implicit or
   * explicit call of `asConcurrentMap(java.util.concurrent.ConcurrentMap)`
   * then the original Java `ConcurrentMap` will be returned.
   *
   * @param m The Scala `concurrent.Map` to be converted.
   * @return An object with an `asJava` method that returns a Java
   *         `ConcurrentMap` view of the argument.
   */
  implicit def mapAsJavaConcurrentMapConverter[A, B](m: concurrent.Map[A, B]): AsJava[juc.ConcurrentMap[A, B]] =
    new AsJava(mapAsJavaConcurrentMap(m))
}