alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Scala example source code file (JavaConversions.scala)

This example Scala source code file (JavaConversions.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, anyref, b, b, int, iterable, iterator, none, none, option, some, some, string

The Scala JavaConversions.scala source code

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2006-2011, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://www.scala-lang.org/           **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */

package scala.collection

/**   A collection of implicit conversions supporting interoperability between
 *    Scala and Java collections.
 *
 *    The following conversions are supported:
 *{{{
 *    scala.collection.Iterable <=> java.lang.Iterable
 *    scala.collection.Iterable <=> java.util.Collection
 *    scala.collection.Iterator <=> java.util.{ Iterator, Enumeration }
 *    scala.collection.mutable.Buffer <=> java.util.List
 *    scala.collection.mutable.Set <=> java.util.Set
 *    scala.collection.mutable.Map <=> java.util.{ Map, Dictionary }
 *    scala.collection.mutable.ConcurrentMap <=> 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, eg.
 *
 *{{{
 *    import scala.collection.JavaConversions._
 * 
 *    val sl = new scala.collection.mutable.ListBuffer[Int]
 *    val jl : java.util.List[Int] = sl
 *    val sl2 : scala.collection.mutable.Buffer[Int] = jl
 *    assert(sl eq sl2)
 *}}}
 *  In addition, the following one way conversions are provided:
 *
 *{{{
 *    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
 *    java.util.Properties         => scala.collection.mutable.Map[String, String]
 *}}}
 * 
 *  @author Miles Sabin
 *  @author Martin Odersky
 *  @since  2.8
 */
object JavaConversions {
  // Note to implementors: the cavalcade of deprecated methods herein should
  // serve as a warning to any who follow: don't overload implicit methods.
  
  import java.{ lang => jl, util => ju }
  import java.util.{ concurrent => juc }

  // Scala => Java

  /**
   * 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.
   * 
   * @param i The Iterator to be converted.
   * @return A Java Iterator view of the argument.
   */
  implicit def asJavaIterator[A](i : Iterator[A]): ju.Iterator[A] = i match {
    case JIteratorWrapper(wrapped) => wrapped
    case _ => IteratorWrapper(i)
  }

  @deprecated("use asJavaIterator instead", "2.8.1")
  def asIterator[A](i : Iterator[A]): ju.Iterator[A] = asJavaIterator[A](i)

  /**
   * 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 A Java Enumeration view of the argument.
   */
  implicit def asJavaEnumeration[A](i : Iterator[A]): ju.Enumeration[A] = i match {
    case JEnumerationWrapper(wrapped) => wrapped
    case _ => IteratorWrapper(i)
  }

  @deprecated("use asJavaEnmeration instead", "2.8.1")
  def asEnumeration[A](i : Iterator[A]): ju.Enumeration[A] = asJavaEnumeration[A](i)

  /**
   * 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 A Java Iterable view of the argument.
   */
  implicit def asJavaIterable[A](i : Iterable[A]): jl.Iterable[A] = i match {
    case JIterableWrapper(wrapped) => wrapped
    case _ => IterableWrapper(i)
  }

  @deprecated("use asJavaIterable instead", "2.8.1")
  def asIterable[A](i : Iterable[A]): jl.Iterable[A] = asJavaIterable[A](i)

  /**
   * 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 A Java Collection view of the argument.
   */
  implicit def asJavaCollection[A](i : Iterable[A]): ju.Collection[A] = i match {
    case JCollectionWrapper(wrapped) => wrapped
    case _ => new IterableWrapper(i)
  }
  
  @deprecated("use asJavaCollection instead", "2.8.1")
  def asCollection[A](i : Iterable[A]): ju.Collection[A] = asJavaCollection[A](i)

  /**
   * 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 A Java List view of the argument.
   */
  implicit def bufferAsJavaList[A](b : mutable.Buffer[A]): ju.List[A] = b match {
    case JListWrapper(wrapped) => wrapped
    case _ => new MutableBufferWrapper(b)
  }
  @deprecated("use bufferAsJavaList instead", "2.9.0")
  def asJavaList[A](b : mutable.Buffer[A]): ju.List[A] = bufferAsJavaList[A](b)
  @deprecated("use bufferAsJavaList instead", "2.8.1")
  def asList[A](b : mutable.Buffer[A]): ju.List[A] = bufferAsJavaList[A](b)

  /**
   * 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 A Java List view of the argument.
   */
  implicit def mutableSeqAsJavaList[A](b : mutable.Seq[A]): ju.List[A] = b match {
    case JListWrapper(wrapped) => wrapped
    case _ => new MutableSeqWrapper(b)
  }
  @deprecated("use mutableSeqAsJavaList instead", "2.9.0")
  def asJavaList[A](b : mutable.Seq[A]): ju.List[A] = mutableSeqAsJavaList[A](b)
  @deprecated("use mutableSeqAsJavaList instead", "2.8.1")
  def asList[A](b : mutable.Seq[A]): ju.List[A] = mutableSeqAsJavaList[A](b)

  /**
   * 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 A Java List view of the argument.
   */
  implicit def seqAsJavaList[A](b : Seq[A]): ju.List[A] = b match {
    case JListWrapper(wrapped) => wrapped
    case _ => new SeqWrapper(b)
  }

  @deprecated("use seqAsJavaList instead", "2.9.0")
  def asJavaList[A](b : Seq[A]): ju.List[A] = seqAsJavaList[A](b)
  @deprecated("use seqAsJavaList instead", "2.8.1")
  def asList[A](b : Seq[A]): ju.List[A] = seqAsJavaList[A](b)

  /**
   * 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 A Java Set view of the argument.
   */
  implicit def mutableSetAsJavaSet[A](s : mutable.Set[A]): ju.Set[A] = s match {
    case JSetWrapper(wrapped) => wrapped
    case _ => new MutableSetWrapper(s)
  }

  @deprecated("use mutableSetAsJavaSet instead", "2.9.0")
  def asJavaSet[A](s : mutable.Set[A]): ju.Set[A] = mutableSetAsJavaSet[A](s)
  @deprecated("use mutableSetAsJavaSet instead", "2.8.1")
  def asSet[A](s : mutable.Set[A]): ju.Set[A] = mutableSetAsJavaSet[A](s)

  /**
   * 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 A Java Set view of the argument.
   */
  implicit def setAsJavaSet[A](s: Set[A]): ju.Set[A] = s match {
    case JSetWrapper(wrapped) => wrapped
    case _ => new SetWrapper(s)
  }

  @deprecated("use setAsJavaSet instead", "2.9.0")
  def asJavaSet[A](s: Set[A]): ju.Set[A] = setAsJavaSet[A](s)
  @deprecated("use setAsJavaSet instead", "2.8.1")
  def asSet[A](s : Set[A]): ju.Set[A] = setAsJavaSet[A](s)

  /**
   * 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 A Java Map view of the argument.
   */
  implicit def mutableMapAsJavaMap[A, B](m : mutable.Map[A, B]): ju.Map[A, B] = m match {
    //case JConcurrentMapWrapper(wrapped) => wrapped
    case JMapWrapper(wrapped) => wrapped
    case _ => new MutableMapWrapper(m)
  }

  @deprecated("use mutableMapAsJavaMap instead", "2.9.0")
  def asJavaMap[A, B](m : mutable.Map[A, B]): ju.Map[A, B] = mutableMapAsJavaMap[A, B](m)
  @deprecated("use mutableMapAsJavaMap instead", "2.8.1")
  def asMap[A, B](m : mutable.Map[A, B]): ju.Map[A, B] = mutableMapAsJavaMap[A, B](m)

  /**
   * 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 A Java Dictionary view of the argument.
   */
  implicit def asJavaDictionary[A, B](m : mutable.Map[A, B]): ju.Dictionary[A, B] = m match {
    //case JConcurrentMapWrapper(wrapped) => wrapped
    case JDictionaryWrapper(wrapped) => wrapped
    case _ => new DictionaryWrapper(m)
  }

  @deprecated("use asJavaDictionary instead", "2.8.1")
  def asDictionary[A, B](m : mutable.Map[A, B]): ju.Dictionary[A, B] = asJavaDictionary[A, B](m)

  /**
   * 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 A Java Map view of the argument.
   */
  implicit def mapAsJavaMap[A, B](m : Map[A, B]): ju.Map[A, B] = m match {
    //case JConcurrentMapWrapper(wrapped) => wrapped
    case JMapWrapper(wrapped) => wrapped
    case _ => new MapWrapper(m)
  }
  
  @deprecated("use mapAsJavaMap instead", "2.9.0")
  def asJavaMap[A, B](m : Map[A, B]): ju.Map[A, B] = mapAsJavaMap[A, B](m)
  @deprecated("use mapAsJavaMap instead", "2.8.1")
  def asMap[A, B](m : Map[A, B]): ju.Map[A, B] = mapAsJavaMap[A, B](m)

  /**
   * Implicitly converts a Scala mutable `ConcurrentMap` to a Java `ConcurrentMap`.
   * The returned Java `ConcurrentMap` is backed by the provided Scala `ConcurrentMap`
   * and any side-effects of using it via the Java interface will be visible
   * via the Scala interface and vice versa.
   * 
   * If the Scala ConcurrentMap was previously obtained from an implicit or
   * explicit call of asConcurrentMap(java.util.concurrect.ConcurrentMap) then the original
   * Java ConcurrentMap will be returned.
   * 
   * @param m The ConcurrentMap to be converted.
   * @return A Java ConcurrentMap view of the argument.
   */
  implicit def asJavaConcurrentMap[A, B](m: mutable.ConcurrentMap[A, B]): juc.ConcurrentMap[A, B] = m match {
    case JConcurrentMapWrapper(wrapped) => wrapped
    case _ => new ConcurrentMapWrapper(m)
  }

  @deprecated("use asJavaConcurrentMap instead", "2.8.1")
  def asConcurrentMap[A, B](m: mutable.ConcurrentMap[A, B]): juc.ConcurrentMap[A, B] = asJavaConcurrentMap[A, B](m)

  // Java => Scala
  
  /**
   * Implicitly converts a Java Iterator to a Scala Iterator.
   * The returned Scala Iterator is backed by the provided Java
   * Iterator and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java Iterator was previously obtained from an implicit or
   * explicit call of asIterator(scala.collection.Iterator) then the original
   * Scala Iterator will be returned.
   * 
   * @param i The Iterator to be converted.
   * @return A Scala Iterator view of the argument.
   */
  implicit def asScalaIterator[A](i : ju.Iterator[A]): Iterator[A] = i match {
    case IteratorWrapper(wrapped) => wrapped
    case _ => JIteratorWrapper(i)
  }

  @deprecated("use asScalaIterator instead", "2.8.1")
  def asIterator[A](i : ju.Iterator[A]): Iterator[A] = asScalaIterator[A](i)
  
  /**
   * Implicitly converts a Java Enumeration to a Scala Iterator.
   * The returned Scala Iterator is backed by the provided Java
   * Enumeration and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java Enumeration was previously obtained from an implicit or
   * explicit call of enumerationAsScalaIterator(scala.collection.Iterator) then the
   * original Scala Iterator will be returned.
   * 
   * @param i The Enumeration to be converted.
   * @return A Scala Iterator view of the argument.
   */
  implicit def enumerationAsScalaIterator[A](i : ju.Enumeration[A]): Iterator[A] = i match {
    case IteratorWrapper(wrapped) => wrapped
    case _ => JEnumerationWrapper(i)
  }
  
  @deprecated("use enumerationAsScalaIterator instead", "2.8.1")
  def asIterator[A](i : ju.Enumeration[A]): Iterator[A] = enumerationAsScalaIterator[A](i)

  /**
   * Implicitly converts a Java Iterable to a Scala Iterable.
   * The returned Scala Iterable is backed by the provided Java
   * Iterable and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java Iterable was previously obtained from an implicit or
   * explicit call of iterableAsScalaIterable(scala.collection.Iterable) then the original
   * Scala Iterable will be returned.
   * 
   * @param i The Iterable to be converted.
   * @return A Scala Iterable view of the argument.
   */
  implicit def iterableAsScalaIterable[A](i : jl.Iterable[A]): Iterable[A] = i match {
    case IterableWrapper(wrapped) => wrapped
    case _ => JIterableWrapper(i)
  }
  
  @deprecated("use iterableAsScalaIterable instead", "2.9.0")
  def asScalaIterable[A](i : jl.Iterable[A]): Iterable[A] = iterableAsScalaIterable[A](i)
  @deprecated("use iterableAsScalaIterable instead", "2.8.1")
  def asIterable[A](i : jl.Iterable[A]): Iterable[A] = iterableAsScalaIterable[A](i)

  /**
   * Implicitly converts a Java Collection to an Scala Iterable.
   * 
   * If the Java Collection was previously obtained from an implicit or
   * explicit call of collectionAsScalaIterable(scala.collection.SizedIterable) then
   * the original Scala Iterable will be returned.
   * 
   * @param i The Collection to be converted.
   * @return A Scala Iterable view of the argument.
   */
  implicit def collectionAsScalaIterable[A](i : ju.Collection[A]): Iterable[A] = i match {
    case IterableWrapper(wrapped) => wrapped
    case _ => JCollectionWrapper(i)
  }
  @deprecated("use collectionAsScalaIterable instead", "2.9.0")
  def asScalaIterable[A](i : ju.Collection[A]): Iterable[A] = collectionAsScalaIterable[A](i)
  @deprecated("use collectionAsScalaIterable instead", "2.8.1")
  def asIterable[A](i : ju.Collection[A]): Iterable[A] = collectionAsScalaIterable[A](i)

  /**
   * Implicitly converts a Java List to a Scala mutable Buffer.
   * The returned Scala Buffer is backed by the provided Java
   * List and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java List was previously obtained from an implicit or
   * explicit call of asScalaBuffer(scala.collection.mutable.Buffer) then the original
   * Scala Buffer will be returned.
   * 
   * @param l The List to be converted.
   * @return A Scala mutable Buffer view of the argument.
   */
  implicit def asScalaBuffer[A](l : ju.List[A]): mutable.Buffer[A] = l match {
    case MutableBufferWrapper(wrapped) => wrapped
    case _ =>new JListWrapper(l)
  }

  @deprecated("use asScalaBuffer instead", "2.8.1")
  def asBuffer[A](l : ju.List[A]): mutable.Buffer[A] = asScalaBuffer[A](l)

  /**
   * Implicitly converts a Java Set to a Scala mutable Set.
   * The returned Scala Set is backed by the provided Java
   * Set and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java Set was previously obtained from an implicit or
   * explicit call of asScalaSet(scala.collection.mutable.Set) then the original
   * Scala Set will be returned.
   * 
   * @param s The Set to be converted.
   * @return A Scala mutable Set view of the argument.
   */
  implicit def asScalaSet[A](s : ju.Set[A]): mutable.Set[A] = s match {
    case MutableSetWrapper(wrapped) => wrapped
    case _ =>new JSetWrapper(s)
  }
  
  @deprecated("use asScalaSet instead", "2.8.1")
  def asSet[A](s : ju.Set[A]): mutable.Set[A] = asScalaSet[A](s)

  /**
   * Implicitly converts a Java Map to a Scala mutable Map.
   * The returned Scala Map is backed by the provided Java
   * Map and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java Map was previously obtained from an implicit or
   * explicit call of mapAsScalaMap(scala.collection.mutable.Map) then the original
   * Scala Map will be returned.
   * 
   * @param m The Map to be converted.
   * @return A Scala mutable Map view of the argument.
   */
  implicit def mapAsScalaMap[A, B](m : ju.Map[A, B]): mutable.Map[A, B] = m match {
    //case ConcurrentMapWrapper(wrapped) => wrapped
    case MutableMapWrapper(wrapped) => wrapped
    case _ => new JMapWrapper(m)
  }

  @deprecated("use mapAsScalaMap instead", "2.9.0")
  def asScalaMap[A, B](m : ju.Map[A, B]): mutable.Map[A, B] = mapAsScalaMap[A, B](m)
  @deprecated("use mapAsScalaMap instead", "2.8.1")
  def asMap[A, B](m : ju.Map[A, B]): mutable.Map[A, B] = mapAsScalaMap[A, B](m)

  /**
   * Implicitly converts a Java ConcurrentMap to a Scala mutable ConcurrentMap.
   * The returned Scala ConcurrentMap is backed by the provided Java
   * ConcurrentMap and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * If the Java ConcurrentMap was previously obtained from an implicit or
   * explicit call of asConcurrentMap(scala.collection.mutable.ConcurrentMap) then the original
   * Scala ConcurrentMap will be returned.
   * 
   * @param m The ConcurrentMap to be converted.
   * @return A Scala mutable ConcurrentMap view of the argument.
   */
  implicit def asScalaConcurrentMap[A, B](m: juc.ConcurrentMap[A, B]): mutable.ConcurrentMap[A, B] = m match {
    case cmw: ConcurrentMapWrapper[a, b] => cmw.underlying
    case _ => new JConcurrentMapWrapper(m)
  }
  
  @deprecated("use asScalaConcurrentMap instead", "2.8.1")
  def asConcurrentMap[A, B](m: juc.ConcurrentMap[A, B]): mutable.ConcurrentMap[A, B] = asScalaConcurrentMap[A, B](m)

  /**
   * Implicitly converts a Java Dictionary to a Scala mutable Map[String, String].
   * The returned Scala Map[String, String] is backed by the provided Java
   * Dictionary and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * @param m The Dictionary to be converted.
   * @return A Scala mutable Map[String, String] view of the argument.
   */
  implicit def dictionaryAsScalaMap[A, B](p: ju.Dictionary[A, B]): mutable.Map[A, B] = p match {
    case DictionaryWrapper(wrapped) => wrapped
    case _ => new JDictionaryWrapper(p)
  }

  @deprecated("use dictionaryAsScalaMap instead", "2.8.1")
  def asMap[A, B](p: ju.Dictionary[A, B]): mutable.Map[A, B] = dictionaryAsScalaMap[A, B](p)

  /**
   * Implicitly converts a Java Properties to a Scala mutable Map[String, String].
   * The returned Scala Map[String, String] is backed by the provided Java
   * Properties and any side-effects of using it via the Scala interface will
   * be visible via the Java interface and vice versa.
   * 
   * @param m The Properties to be converted.
   * @return A Scala mutable Map[String, String] view of the argument.
   */
  implicit def propertiesAsScalaMap(p: ju.Properties): mutable.Map[String, String] = p match {
    case _ => new JPropertiesWrapper(p)
  }

  @deprecated("use propertiesAsScalaMap instead", "2.9.0")
  def asScalaMap(p: ju.Properties): mutable.Map[String, String] = propertiesAsScalaMap(p)
  @deprecated("use propertiesAsScalaMap instead", "2.8.1")
  def asMap(p: ju.Properties): mutable.Map[String, String] = propertiesAsScalaMap(p)

  // Private implementations (shared by JavaConverters) ...
  
  trait IterableWrapperTrait[A] extends ju.AbstractCollection[A] {
    val underlying: Iterable[A]
    def size = underlying.size
    override def iterator = IteratorWrapper(underlying.iterator)
    override def isEmpty = underlying.isEmpty
  }

  case class IteratorWrapper[A](underlying : Iterator[A]) extends ju.Iterator[A] with ju.Enumeration[A] {
    def hasNext = underlying.hasNext
    def next() = underlying.next
    def hasMoreElements = underlying.hasNext
    def nextElement() = underlying.next
    def remove() = throw new UnsupportedOperationException
  }

  class ToIteratorWrapper[A](underlying : Iterator[A]) {
    def asJava = new IteratorWrapper(underlying)
  }

  case class JIteratorWrapper[A](underlying : ju.Iterator[A]) extends Iterator[A] {
    def hasNext = underlying.hasNext
    def next() = underlying.next
  }

  case class JEnumerationWrapper[A](underlying : ju.Enumeration[A]) extends Iterator[A] {
    def hasNext = underlying.hasMoreElements
    def next() = underlying.nextElement
  }

  case class IterableWrapper[A](underlying : Iterable[A])
                extends ju.AbstractCollection[A]
                   with IterableWrapperTrait[A] { }

  case class JIterableWrapper[A](underlying : jl.Iterable[A]) extends Iterable[A] {
    def iterator = underlying.iterator
    def newBuilder[B] = new mutable.ArrayBuffer[B]
  }

  case class JCollectionWrapper[A](underlying : ju.Collection[A]) extends Iterable[A] {
    def iterator = underlying.iterator
    override def size = underlying.size
    override def isEmpty = underlying.isEmpty
    def newBuilder[B] = new mutable.ArrayBuffer[B]
  }
  
  case class SeqWrapper[A](underlying : Seq[A]) extends ju.AbstractList[A] with IterableWrapperTrait[A] {
    def get(i : Int) = underlying(i)
  }
  
  case class MutableSeqWrapper[A](underlying : mutable.Seq[A]) extends ju.AbstractList[A] with IterableWrapperTrait[A] {
    def get(i : Int) = underlying(i)
    override def set(i : Int, elem: A) = { val p = underlying(i) ; underlying(i) = elem ; p }
  }
  
  case class MutableBufferWrapper[A](underlying : mutable.Buffer[A]) extends ju.AbstractList[A] with IterableWrapperTrait[A] {
    def get(i : Int) = underlying(i)
    override def set(i : Int, elem: A) = { val p = underlying(i) ; underlying(i) = elem ; p }
    override def add(elem : A) = { underlying.append(elem) ; true }
    override def remove(i : Int) = underlying.remove(i)
  }
  
  case class JListWrapper[A](val underlying : ju.List[A]) extends mutable.Buffer[A] {
    def length = underlying.size
    override def isEmpty = underlying.isEmpty
    override def iterator : Iterator[A] = underlying.iterator
    def apply(i : Int) = underlying.get(i)
    def update(i : Int, elem : A) = underlying.set(i, elem)
    def +=:(elem : A) = { underlying.subList(0, 0).add(elem) ; this } 
    def +=(elem : A): this.type = { underlying.add(elem); this }
    def insertAll(i : Int, elems : Traversable[A]) = { val ins = underlying.subList(0, i) ;  elems.seq.foreach(ins.add(_)) }
    def remove(i : Int) = underlying.remove(i)
    def clear = underlying.clear
    def result = this
  }
  
  class SetWrapper[A](underlying: Set[A]) extends ju.AbstractSet[A] {
    self =>
    def size = underlying.size
    def iterator = new ju.Iterator[A] {
      val ui = underlying.iterator
      var prev : Option[A] = None
      def hasNext = ui.hasNext
      def next = { val e = ui.next ; prev = Some(e) ; e }
      def remove = prev match {
        case Some(e) => 
          underlying match {
            case ms: mutable.Set[a] => 
              ms.remove(e.asInstanceOf[a])
              prev = None
            case _ =>
              throw new UnsupportedOperationException("remove")
          }
        case _ => throw new IllegalStateException("next must be called at least once before remove")
      }
    }
  }

  case class MutableSetWrapper[A](underlying : mutable.Set[A]) extends SetWrapper[A](underlying) {
    override def add(elem: A) = { val sz = underlying.size ; underlying += elem ; sz < underlying.size }
    override def remove(elem : AnyRef) = try {
      underlying.remove(elem.asInstanceOf[A])
    } catch {
      case ex: ClassCastException => false
    }
    override def clear() = underlying.clear()
  }
  
  case class JSetWrapper[A](underlying : ju.Set[A]) extends mutable.Set[A] with mutable.SetLike[A, JSetWrapper[A]] {
    override def size = underlying.size

    def iterator = underlying.iterator
  
    def contains(elem: A): Boolean = underlying.contains(elem)
  
    def +=(elem: A): this.type = { underlying.add(elem); this }
    def -=(elem: A): this.type = { underlying.remove(elem); this }

    override def add(elem: A): Boolean = underlying.add(elem)
    override def remove(elem: A): Boolean = underlying.remove(elem)
    override def clear() = underlying.clear()

    override def empty = JSetWrapper(new ju.HashSet[A])
  }

  class MapWrapper[A, B](underlying: Map[A, B]) extends ju.AbstractMap[A, B] { self =>
    override def size = underlying.size

    override def get(key: AnyRef): B = try {
      underlying get key.asInstanceOf[A] match {
        case None => null.asInstanceOf[B]
        case Some(v) => v
      }
    } catch {
      case ex: ClassCastException => null.asInstanceOf[B]
    }

    override def entrySet: ju.Set[ju.Map.Entry[A, B]] = new ju.AbstractSet[ju.Map.Entry[A, B]] {
      def size = self.size

      def iterator = new ju.Iterator[ju.Map.Entry[A, B]] {
        val ui = underlying.iterator
        var prev : Option[A] = None
        
        def hasNext = ui.hasNext
      
        def next() = {
          val (k, v) = ui.next
          prev = Some(k)
          new ju.Map.Entry[A, B] {
            def getKey = k
            def getValue = v
            def setValue(v1 : B) = self.put(k, v1)
            override def hashCode = k.hashCode + v.hashCode
            override def equals(other: Any) = other match {
              case e : ju.Map.Entry[_, _] => k == e.getKey && v == e.getValue
              case _ => false
            }
          }
        }
        
        def remove() = prev match {
          case Some(k) => 
            underlying match {
              case mm: mutable.Map[a, _] =>
                val v = mm.remove(k.asInstanceOf[a])
                prev = None
                v
              case _ =>
                throw new UnsupportedOperationException("remove")
            }
          case _ => 
            throw new IllegalStateException("next must be called at least once before remove")
        }
      }
    }
  }

  case class MutableMapWrapper[A, B](underlying: mutable.Map[A, B])
  extends MapWrapper[A, B](underlying) {
    override def put(k : A, v : B) = underlying.put(k, v) match {
      case Some(v1) => v1
      case None => null.asInstanceOf[B]
    }
    
    override def remove(k : AnyRef): B = try {
      underlying.remove(k.asInstanceOf[A]) match {
        case None => null.asInstanceOf[B]
        case Some(v) => v
      }
    } catch {
      case ex: ClassCastException => null.asInstanceOf[B]
    }

    override def clear() = underlying.clear()
  }
  
  trait JMapWrapperLike[A, B, +Repr <: mutable.MapLike[A, B, Repr] with mutable.Map[A, B]]
  extends mutable.Map[A, B] with mutable.MapLike[A, B, Repr] {
    def underlying: ju.Map[A, B]
    
    override def size = underlying.size
    
    def get(k : A) = {
      val v = underlying.get(k)
      if (v != null)
        Some(v)
      else if(underlying.containsKey(k))
        Some(null.asInstanceOf[B])
      else
        None
    }

    def +=(kv: (A, B)): this.type = { underlying.put(kv._1, kv._2); this }
    def -=(key: A): this.type = { underlying.remove(key); this }

    override def put(k : A, v : B): Option[B] = {
      val r = underlying.put(k, v)
      if (r != null) Some(r) else None
    }
    
    override def update(k : A, v : B) { underlying.put(k, v) }
    
    override def remove(k : A): Option[B] = { 
      val r = underlying.remove(k)
      if (r != null) Some(r) else None
    }

    def iterator = new Iterator[(A, B)] {
      val ui = underlying.entrySet.iterator
      def hasNext = ui.hasNext
      def next() = { val e = ui.next ; (e.getKey, e.getValue) }
    }
    
    override def clear() = underlying.clear()
    
    override def empty: Repr = null.asInstanceOf[Repr]
  }
  
  case class JMapWrapper[A, B](val underlying : ju.Map[A, B])
  extends JMapWrapperLike[A, B, JMapWrapper[A, B]] {
    override def empty = JMapWrapper(new ju.HashMap[A, B])
  }
  
  class ConcurrentMapWrapper[A, B](override val underlying: mutable.ConcurrentMap[A, B])
  extends MutableMapWrapper[A, B](underlying) with juc.ConcurrentMap[A, B] {
    
    def putIfAbsent(k: A, v: B) = underlying.putIfAbsent(k, v) match {
      case Some(v) => v
      case None => null.asInstanceOf[B]
    }
    
    def remove(k: AnyRef, v: AnyRef) = try {
      underlying.remove(k.asInstanceOf[A], v.asInstanceOf[B])
    } catch {
      case ex: ClassCastException =>
        false
    }
    
    def replace(k: A, v: B): B = underlying.replace(k, v) match {
      case Some(v) => v
      case None => null.asInstanceOf[B]
    }
    
    def replace(k: A, oldval: B, newval: B) = underlying.replace(k, oldval, newval)
  }
  
  case class JConcurrentMapWrapper[A, B](val underlying: juc.ConcurrentMap[A, B])
  extends JMapWrapperLike[A, B, JConcurrentMapWrapper[A, B]] with mutable.ConcurrentMap[A, B] {
    override def get(k: A) = {
      val v = underlying.get(k)
      if (v != null) Some(v)
      else None
    }
    
    override def empty = new JConcurrentMapWrapper(new juc.ConcurrentHashMap[A, B])
    
    def putIfAbsent(k: A, v: B): Option[B] = {
      val r = underlying.putIfAbsent(k, v)
      if (r != null) Some(r) else None
    }
    
    def remove(k: A, v: B): Boolean = underlying.remove(k, v)
    
    def replace(k: A, v: B): Option[B] = {
      val prev = underlying.replace(k, v)
      if (prev != null) Some(prev) else None
    }
    
    def replace(k: A, oldvalue: B, newvalue: B): Boolean = underlying.replace(k, oldvalue, newvalue)
  }
  
  case class DictionaryWrapper[A, B](underlying: mutable.Map[A, B])
  extends ju.Dictionary[A, B] {
    def size: Int = underlying.size
    def isEmpty: Boolean = underlying.isEmpty
    def keys: ju.Enumeration[A] = asJavaEnumeration(underlying.keysIterator)
    def elements: ju.Enumeration[B] = asJavaEnumeration(underlying.valuesIterator)
    def get(key: AnyRef) = try {
      underlying.get(key.asInstanceOf[A]) match {
        case None => null.asInstanceOf[B]
        case Some(v) => v
      }
    } catch {
      case ex: ClassCastException => null.asInstanceOf[B]
    }
    def put(key: A, value: B): B = underlying.put(key, value) match {
      case Some(v) => v
      case None => null.asInstanceOf[B]
    }
    override def remove(key: AnyRef) = try {
      underlying.remove(key.asInstanceOf[A]) match {
        case None => null.asInstanceOf[B]
        case Some(v) => v
      }
    } catch {
      case ex: ClassCastException => null.asInstanceOf[B]
    }
  }

  case class JDictionaryWrapper[A, B](underlying: ju.Dictionary[A, B])
  extends mutable.Map[A, B] {

    override def size: Int = underlying.size

    def get(k : A) = {
      val v = underlying.get(k)
      if (v != null) Some(v) else None
    }

    def +=(kv: (A, B)): this.type = { underlying.put(kv._1, kv._2); this }
    def -=(key: A): this.type = { underlying.remove(key); this }

    override def put(k : A, v : B): Option[B] = {
      val r = underlying.put(k, v)
      if (r != null) Some(r) else None
    }
    
    override def update(k : A, v : B) { underlying.put(k, v) }
    
    override def remove(k : A): Option[B] = { 
      val r = underlying.remove(k)
      if (r != null) Some(r) else None
    }

    def iterator = enumerationAsScalaIterator(underlying.keys) map (k => (k, underlying get k))
    
    override def clear() = underlying.clear()
  }

  case class JPropertiesWrapper(underlying: ju.Properties)
  extends mutable.Map[String, String] with mutable.MapLike[String, String, JPropertiesWrapper] {
    override def size = underlying.size
    
    def get(k : String) = {
      val v = underlying.get(k)
      if (v != null)
        Some(v.asInstanceOf[String])
      else
        None
    }

    def +=(kv: (String, String)): this.type = { underlying.put(kv._1, kv._2); this }
    def -=(key: String): this.type = { underlying.remove(key); this }

    override def put(k : String, v : String): Option[String] = {
      val r = underlying.put(k, v)
      if (r != null) Some(r.asInstanceOf[String]) else None
    }
    
    override def update(k : String, v : String) { underlying.put(k, v) }
    
    override def remove(k : String): Option[String] = { 
      val r = underlying.remove(k)
      if (r != null) Some(r.asInstanceOf[String]) else None
    }

    def iterator = new Iterator[(String, String)] {
      val ui = underlying.entrySet.iterator
      def hasNext = ui.hasNext
      def next() = { val e = ui.next ; (e.getKey.asInstanceOf[String], e.getValue.asInstanceOf[String]) }
    }
    
    override def clear() = underlying.clear()
    
    override def empty = JPropertiesWrapper(new ju.Properties)
    
    def getProperty(key: String) = underlying.getProperty(key)
    
    def getProperty(key: String, defaultValue: String) = underlying.getProperty(key, defaultValue)
    
    def setProperty(key: String, value: String) = underlying.setProperty(key, value)
  }
}

Other Scala examples (source code examples)

Here is a short list of links related to this Scala JavaConversions.scala source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.