CollectionConverters
This object provides extension methods that convert between Scala and Java collections.
When writing Java code, use the explicit conversion methods defined in javaapi.CollectionConverters instead.
Note: to create Java Streams that operate on Scala collections (sequentially or in parallel), use StreamConverters.
import scala.jdk.CollectionConverters._
val s: java.util.Set[String] = Set("one", "two").asJava
The conversions return adapters for the corresponding API, i.e., the collections are wrapped, not converted. Changes to the original collection are reflected in the view, and vice versa:
scala> import scala.jdk.CollectionConverters._
scala> val s = collection.mutable.Set("one")
s: scala.collection.mutable.Set[String] = HashSet(one)
scala> val js = s.asJava
js: java.util.Set[String] = [one]
scala> js.add("two")
scala> s
res2: scala.collection.mutable.Set[String] = HashSet(two, one)
The following conversions are supported via asScala
and asJava
:
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.concurrent.Map <=> java.util.concurrent.ConcurrentMap
The following conversions are supported via asScala
and through specially-named extension methods to convert to Java collections, as shown:
scala.collection.Iterable <=> java.util.Collection (via asJavaCollection)
scala.collection.Iterator <=> java.util.Enumeration (via asJavaEnumeration)
scala.collection.mutable.Map <=> java.util.Dictionary (via asJavaDictionary)
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
In all cases, converting from a source type to a target type and back again will return the original source object. For example:
import scala.jdk.CollectionConverters._
val source = new scala.collection.mutable.ListBuffer[Int]
val target: java.util.List[Int] = source.asJava
val other: scala.collection.mutable.Buffer[Int] = target.asScala
assert(source eq other)
Attributes
- Source
- CollectionConverters.scala
- Graph
-
- Supertypes
- Self type
-
CollectionConverters.type
Members list
Type members
Inherited classlikes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
- Supertypes
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
- Supertypes
Implicits
Inherited implicits
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsJavaExtensions
- Source
- AsJavaExtensions.scala
Attributes
- Inherited from:
- AsScalaExtensions
- Source
- AsScalaExtensions.scala