scala.collection.JavaConverters

object JavaConverters extends DecorateAsJava with DecorateAsScala

A collection of decorators that allow converting 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 are also supported, but the direction from Scala to Java is done by the more specifically named methods: 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

The following one way conversion is provided via asScala :

Value Members From scala.collection.convert.DecorateAsJava

implicit def asJavaCollectionConverter[A](i: Iterable[A]): convert.Decorators.AsJavaCollection[A]

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.

  • i
    • The SizedIterable to be converted.
  • returns
    • An object with an asJava method that returns a Java Collection view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def asJavaDictionaryConverter[A, B](m: mutable.Map[A, B]): convert.Decorators.AsJavaDictionary[A, B]

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.

  • m
    • The Map to be converted.
  • returns
    • An object with an asJavaDictionary method that returns a Java Dictionary view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def asJavaEnumerationConverter[A](i: Iterator[A]): convert.Decorators.AsJavaEnumeration[A]

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.

  • i
    • The Iterator to be converted.
  • returns
    • An object with an asJavaEnumeration method that returns a Java Enumeration view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def asJavaIterableConverter[A](i: Iterable[A]): convert.Decorators.AsJava[java.lang.Iterable[A]]

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.

  • i
    • The Iterable to be converted.
  • returns
    • An object with an asJavaCollection method that returns a Java Iterable view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def asJavaIteratorConverter[A](i: Iterator[A]): convert.Decorators.AsJava[java.util.Iterator[A]]

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.

  • i
    • The Iterator to be converted.
  • returns
    • An object with an asJava method that returns a Java Iterator view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def bufferAsJavaListConverter[A](b: Buffer[A]): convert.Decorators.AsJava[java.util.List[A]]

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.

  • b
    • The Buffer to be converted.
  • returns
    • An object with an asJava method that returns a Java List view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def mapAsJavaConcurrentMapConverter[A, B](m: concurrent.Map[A, B]): convert.Decorators.AsJava[ConcurrentMap[A, B]]

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.

  • m
    • The Scala concurrent.Map to be converted.
  • returns
    • An object with an asJava method that returns a Java ConcurrentMap view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def mapAsJavaMapConverter[A, B](m: Map[A, B]): convert.Decorators.AsJava[java.util.Map[A, B]]

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.

  • m
    • The Map to be converted.
  • returns
    • An object with an asJava method that returns a Java Map view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def mutableMapAsJavaMapConverter[A, B](m: mutable.Map[A, B]): convert.Decorators.AsJava[java.util.Map[A, B]]

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.

  • m
    • The Map to be converted.
  • returns
    • An object with an asJava method that returns a Java Map view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def mutableSeqAsJavaListConverter[A](b: mutable.Seq[A]): convert.Decorators.AsJava[java.util.List[A]]

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.

  • b
    • The Seq to be converted.
  • returns
    • An object with an asJava method that returns a Java List view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def mutableSetAsJavaSetConverter[A](s: mutable.Set[A]): convert.Decorators.AsJava[java.util.Set[A]]

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.

  • s
    • The Set to be converted.
  • returns
    • An object with an asJava method that returns a Java Set view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def seqAsJavaListConverter[A](b: Seq[A]): convert.Decorators.AsJava[java.util.List[A]]

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.

  • b
    • The Seq to be converted.
  • returns
    • An object with an asJava method that returns a Java List view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

implicit def setAsJavaSetConverter[A](s: Set[A]): convert.Decorators.AsJava[java.util.Set[A]]

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.

  • s
    • The Set to be converted.
  • returns
    • An object with an asJava method that returns a Java Set view of the argument.
  • Definition Classes
    • DecorateAsJava

(defined at scala.collection.convert.DecorateAsJava)

Value Members From scala.collection.convert.DecorateAsScala

implicit def asScalaBufferConverter[A](l: java.util.List[A]): convert.Decorators.AsScala[Buffer[A]]

Adds an asScala method that 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 asList(scala.collection.mutable.Buffer) then the original Scala Buffer will be returned.

  • l
    • The List to be converted.
  • returns
    • An object with an asScala method that returns a Scala mutable Buffer view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def asScalaIteratorConverter[A](i: java.util.Iterator[A]): convert.Decorators.AsScala[Iterator[A]]

Adds an asScala method that 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.

  • i
    • The Iterator to be converted.
  • returns
    • An object with an asScala method that returns a Scala Iterator view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def asScalaSetConverter[A](s: java.util.Set[A]): convert.Decorators.AsScala[mutable.Set[A]]

Adds an asScala method that 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 asSet(scala.collection.mutable.Set) then the original Scala Set will be returned.

  • s
    • The Set to be converted.
  • returns
    • An object with an asScala method that returns a Scala mutable Set view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def collectionAsScalaIterableConverter[A](i: Collection[A]): convert.Decorators.AsScala[Iterable[A]]

Adds an asScala method that implicitly converts a Java Collection to an Scala Iterable .

If the Java Collection was previously obtained from an implicit or explicit call of asCollection(scala.collection.SizedIterable) then the original Scala SizedIterable will be returned.

  • i
    • The Collection to be converted.
  • returns
    • An object with an asScala method that returns a Scala SizedIterable view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def dictionaryAsScalaMapConverter[A, B](p: Dictionary[A, B]): convert.Decorators.AsScala[mutable.Map[A, B]]

Adds an asScala method that 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.

  • p
    • The Dictionary to be converted.
  • returns
    • An object with an asScala method that returns a Scala mutable Map[String, String] view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def enumerationAsScalaIteratorConverter[A](i: java.util.Enumeration[A]): convert.Decorators.AsScala[Iterator[A]]

Adds an asScala method that 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 asEnumeration(scala.collection.Iterator) then the original Scala Iterator will be returned.

  • i
    • The Enumeration to be converted.
  • returns
    • An object with an asScala method that returns a Scala Iterator view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def iterableAsScalaIterableConverter[A](i: java.lang.Iterable[A]): convert.Decorators.AsScala[Iterable[A]]

Adds an asScala method that 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 asIterable(scala.collection.Iterable) then the original Scala Iterable will be returned.

  • i
    • The Iterable to be converted.
  • returns
    • An object with an asScala method that returns a Scala Iterable view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def mapAsScalaConcurrentMapConverter[A, B](m: ConcurrentMap[A, B]): convert.Decorators.AsScala[concurrent.Map[A, B]]

Adds an asScala method that implicitly converts a Java ConcurrentMap to a Scala mutable concurrent.Map . The returned Scala concurrent.Map 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 mapAsScalaConcurrentMap(scala.collection.mutable.ConcurrentMap) then the original Scala concurrent.Map will be returned.

  • m
    • The ConcurrentMap to be converted.
  • returns
    • An object with an asScala method that returns a Scala mutable concurrent.Map view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def mapAsScalaMapConverter[A, B](m: java.util.Map[A, B]): convert.Decorators.AsScala[mutable.Map[A, B]]

Adds an asScala method that 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 asMap(scala.collection.mutable.Map) then the original Scala Map will be returned.

If the wrapped map is synchronized (e.g. from java.util.Collections.synchronizedMap ), it is your responsibility to wrap all non-atomic operations with underlying.synchronized . This includes get , as java.util.Map ‘s API does not allow for an atomic get when null values may be present.

  • m
    • The Map to be converted.
  • returns
    • An object with an asScala method that returns a Scala mutable Map view of the argument.
  • Definition Classes
    • DecorateAsScala

(defined at scala.collection.convert.DecorateAsScala)

implicit def propertiesAsScalaMapConverter(p: Properties): convert.Decorators.AsScala[mutable.Map[String, String]]

Adds an asScala method that 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.

  • p
    • The Properties to be converted.
  • returns
    • An object with an asScala method that returns a Scala mutable Map[String, String] view of the argument.
  • Definition Classes
    • DecorateAsScala (defined at scala.collection.convert.DecorateAsScala)

Full Source:

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

package scala
package collection

import convert._

// TODO: I cleaned all this documentation up in JavaConversions, but the
// documentation in here is basically the pre-cleaned-up version with minor
// additions.  Would be nice to have in one place.

/** A collection of decorators that allow converting 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 are also supported, but the
 *  direction from Scala to Java is done by the more specifically named methods:
 *  `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`
 *
 *  The following one way conversion is provided via `asScala`:
 *
 *  - `java.util.Properties` => `scala.collection.mutable.Map`
 *
 *  @since  2.8.1
 */
object JavaConverters extends DecorateAsJava with DecorateAsScala