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Object scala.collection.JavaConverters

object JavaConverters extends AsJavaConverters with AsScalaConverters

A variety of decorators that enable converting between Scala and Java collections using extension methods, asScala and asJava.

The extension methods return adapters for the corresponding API.

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.collection.JavaConverters._

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)

Alternatively, the conversion methods have descriptive names and can be invoked explicitly.

scala> val vs = java.util.Arrays.asList("hi", "bye")
vs: java.util.List[String] = [hi, bye]

scala> val ss = asScalaIterator(vs.iterator)
ss: Iterator[String] = <iterator>

scala> .toList
res0: List[String] = List(hi, bye)

scala> val ss = asScalaBuffer(vs)
ss: scala.collection.mutable.Buffer[String] = Buffer(hi, bye)

Annotations: @deprecated
Deprecated: (Since version 2.13.0) Use scala.jdk.CollectionConverters instead
Source: JavaConverters.scala
Since: 2.8.1
Linear Supertypes: AsScalaConverters, AsJavaConverters, AnyRef, Any

Type Members

class AsJava[A] extends AnyRef

class AsJavaCollection[A] extends AnyRef

class AsJavaDictionary[K, V] extends AnyRef

class AsJavaEnumeration[A] extends AnyRef

class AsScala[A] extends AnyRef

Value Members

final def !=(arg0: Any): Boolean

Test two objects for inequality.

returns: true if !(this == that), false otherwise.

Definition Classes: AnyRef → Any

final def ##(): Int

Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

returns: a hash value consistent with ==

Definition Classes: AnyRef → Any

final def ==(arg0: Any): Boolean

The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

returns: true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes: AnyRef → Any

final def asInstanceOf[T0]: T0

Cast the receiver object to be of type T0.

Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

returns: the receiver object.

Definition Classes: Any
Exceptions thrown: ClassCastException if the receiver object is not an instance of the erasure of type T0.

def asJava[K, V](m: concurrent.Map[K, V]): ConcurrentMap[K, V]

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 asScala then the original Java ConcurrentMap will be returned.

m: The Scala concurrent.Map to be converted.
returns: A Java ConcurrentMap view of the argument.

Definition Classes: AsJavaConverters

def asJava[K, V](m: Map[K, V]): java.util.Map[K, V]

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 asScala then the original Java Map will be returned.

m: The Scala Map to be converted.
returns: A Java Map view of the argument.

Definition Classes: AsJavaConverters

def asJava[K, V](m: mutable.Map[K, V]): java.util.Map[K, V]

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 asScala then the original Java Map will be returned.

m: The Scala mutable Map to be converted.
returns: A Java Map view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](s: Set[A]): java.util.Set[A]

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 asScala then the original Java Set will be returned.

s: The Scala Set to be converted.
returns: A Java Set view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](s: mutable.Set[A]): java.util.Set[A]

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 asScala then the original Java Set will be returned.

s: The Scala mutable Set to be converted.
returns: A Java Set view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](s: Seq[A]): java.util.List[A]

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 asScala then the original Java List will be returned.

s: The Scala Seq to be converted.
returns: A Java List view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](s: mutable.Seq[A]): java.util.List[A]

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 asScala then the original Java List will be returned.

s: The Scala Seq to be converted.
returns: A Java List view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](b: Buffer[A]): java.util.List[A]

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 asScala then the original Java List will be returned.

b: The Scala Buffer to be converted.
returns: A Java List view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](i: Iterable[A]): java.lang.Iterable[A]

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 asScala then the original Java Iterable will be returned.

i: The Scala Iterable to be converted.
returns: A Java Iterable view of the argument.

Definition Classes: AsJavaConverters

def asJava[A](i: Iterator[A]): java.util.Iterator[A]

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 asScala then the original Java Iterator will be returned.

i: The Scala Iterator to be converted.
returns: A Java Iterator view of the argument.

Definition Classes: AsJavaConverters

def asJavaCollection[A](i: Iterable[A]): Collection[A]

Converts a Scala Iterable to an immutable Java Collection.

If the Scala Iterable was previously obtained from an implicit or explicit call of asScala then the original Java Collection will be returned.

i: The Scala Iterable to be converted.
returns: A Java Collection view of the argument.

Definition Classes: AsJavaConverters

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

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

See also: asJavaCollection

def asJavaDictionary[K, V](m: mutable.Map[K, V]): Dictionary[K, V]

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 Map was previously obtained from an implicit or explicit call of asScala then the original Java Dictionary will be returned.

m: The Scala Map to be converted.
returns: A Java Dictionary view of the argument.

Definition Classes: AsJavaConverters

implicit def asJavaDictionaryConverter[K, V](m: mutable.Map[K, V]): AsJavaDictionary[K, V]

Adds an asJavaDictionary method that implicitly converts a Scala mutable Map to a Java Dictionary.

See also: asJavaDictionary

def asJavaEnumeration[A](i: Iterator[A]): java.util.Enumeration[A]

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 asScala then the original Java Enumeration will be returned.

i: The Scala Iterator to be converted.
returns: A Java Enumeration view of the argument.

Definition Classes: AsJavaConverters

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

Adds an asJavaEnumeration method that implicitly converts a Scala Iterator to a Java Enumeration.

See also: asJavaEnumeration

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

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

See also: asJavaIterable

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

Adds an asJava method that implicitly converts a Scala Iterator to a Java Iterator.

See also: asJavaIterator

def asScala(p: Properties): mutable.Map[String, String]

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 Java Properties to be converted.
returns: A Scala mutable Map[String, String] view of the argument.

Definition Classes: AsScalaConverters

def asScala[A, B](d: Dictionary[A, B]): mutable.Map[A, B]

Converts a Java Dictionary to a Scala mutable Map.

The returned Scala Map 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.

If the Java Dictionary was previously obtained from an implicit or explicit call of asJavaDictionary then the original Scala Map will be returned.

d: The Java Dictionary to be converted.
returns: A Scala mutable Map view of the argument.

Definition Classes: AsScalaConverters

def asScala[A, B](m: ConcurrentMap[A, B]): concurrent.Map[A, B]

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 asJava then the original Scala ConcurrentMap will be returned.

m: The Java ConcurrentMap to be converted.
returns: A Scala mutable ConcurrentMap view of the argument.

Definition Classes: AsScalaConverters

def asScala[A, B](m: java.util.Map[A, B]): mutable.Map[A, B]

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 asJava 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 Java Map to be converted.
returns: A Scala mutable Map view of the argument.

Definition Classes: AsScalaConverters

def asScala[A](s: java.util.Set[A]): mutable.Set[A]

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 asJava then the original Scala Set will be returned.

s: The Java Set to be converted.
returns: A Scala mutable Set view of the argument.

Definition Classes: AsScalaConverters

def asScala[A](l: java.util.List[A]): Buffer[A]

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 asJava then the original Scala Buffer will be returned.

l: The Java List to be converted.
returns: A Scala mutable Buffer view of the argument.

Definition Classes: AsScalaConverters

def asScala[A](c: Collection[A]): Iterable[A]

Converts a Java Collection to a Scala Iterable.

If the Java Collection was previously obtained from an implicit or explicit call of asJavaCollection then the original Scala Iterable will be returned.

c: The Java Collection to be converted.
returns: A Scala Iterable view of the argument.

Definition Classes: AsScalaConverters

def asScala[A](i: java.lang.Iterable[A]): Iterable[A]

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 asJava then the original Scala Iterable will be returned.

i: The Java Iterable to be converted.
returns: A Scala Iterable view of the argument.

Definition Classes: AsScalaConverters

def asScala[A](e: java.util.Enumeration[A]): Iterator[A]

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 asJavaEnumeration then the original Scala Iterator will be returned.

e: The Java Enumeration to be converted.
returns: A Scala Iterator view of the argument.

Definition Classes: AsScalaConverters

def asScala[A](i: java.util.Iterator[A]): Iterator[A]

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 asJava then the original Scala Iterator will be returned.

i: The Java Iterator to be converted.
returns: A Scala Iterator view of the argument.

Definition Classes: AsScalaConverters

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

Adds an asScala method that implicitly converts a Java List to a Scala mutable Buffer.

See also: asScalaBuffer

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

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

See also: asScalaIterator

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

Adds an asScala method that implicitly converts a Java Set to a Scala mutable Set.

See also: asScalaSet

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

Adds an asJava method that implicitly converts a Scala mutable Buffer to a Java List.

See also: bufferAsJavaList

def clone(): AnyRef

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

returns: a copy of the receiver object.

Attributes: protected[java.lang]
Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.CloneNotSupportedException]) @native()
Note: not specified by SLS as a member of AnyRef

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

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

See also: collectionAsScalaIterable

implicit def dictionaryAsScalaMapConverter[K, V](p: Dictionary[K, V]): AsScala[mutable.Map[K, V]]

Adds an asScala method that implicitly converts a Java Dictionary to a Scala mutable Map.

See also: dictionaryAsScalaMap

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

Adds an asScala method that implicitly converts a Java Enumeration to a Scala Iterator.

See also: enumerationAsScalaIterator

final def eq(arg0: AnyRef): Boolean

Tests whether the argument (that) is a reference to the receiver object (this).

The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

x

y

AnyRef

x.eq(y)

true

false

x

AnyRef

x.eq(null)

null.eq(x)

false

null.eq(null)

true

When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

returns: true if the argument is a reference to the receiver object; false otherwise.

Definition Classes: AnyRef

def equals(arg0: AnyRef): Boolean

The equality method for reference types. Default implementation delegates to eq.

def finalize(): Unit

Called by the garbage collector on the receiver object when there are no more references to the object.

The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

Attributes: protected[java.lang]
Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.Throwable])
Note: not specified by SLS as a member of AnyRef

final def getClass(): Class[_ <: AnyRef]

Returns the runtime class representation of the object.

returns: a class object corresponding to the runtime type of the receiver.

Definition Classes: AnyRef → Any
Annotations: @native()

def hashCode(): Int

The hashCode method for reference types. See hashCode in scala.Any.

returns: the hash code value for this object.

Definition Classes: AnyRef → Any
Annotations: @native()

final def isInstanceOf[T0]: Boolean

Test whether the dynamic type of the receiver object is T0.

Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

returns: true if the receiver object is an instance of erasure of type T0; false otherwise.

Definition Classes: Any

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

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

See also: iterableAsScalaIterable

implicit def mapAsJavaConcurrentMapConverter[K, V](m: concurrent.Map[K, V]): AsJava[ConcurrentMap[K, V]]

Adds an asJava method that implicitly converts a Scala mutable concurrent.Map to a Java ConcurrentMap.

See also: mapAsJavaConcurrentMap.

implicit def mapAsJavaMapConverter[K, V](m: Map[K, V]): AsJava[java.util.Map[K, V]]

Adds an asJava method that implicitly converts a Scala Map to a Java Map.

See also: mapAsJavaMap

implicit def mapAsScalaConcurrentMapConverter[K, V](m: ConcurrentMap[K, V]): AsScala[concurrent.Map[K, V]]

Adds an asScala method that implicitly converts a Java ConcurrentMap to a Scala mutable concurrent.Map.

See also: mapAsScalaConcurrentMap

implicit def mapAsScalaMapConverter[K, V](m: java.util.Map[K, V]): AsScala[mutable.Map[K, V]]

Adds an asScala method that implicitly converts a Java Map to a Scala mutable Map.

See also: mapAsScalaMap

implicit def mutableMapAsJavaMapConverter[K, V](m: mutable.Map[K, V]): AsJava[java.util.Map[K, V]]

Adds an asJava method that implicitly converts a Scala mutable Map to a Java Map.

See also: mutableMapAsJavaMap

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

Adds an asJava method that implicitly converts a Scala mutable Seq to a Java List.

See also: mutableSeqAsJavaList

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

Adds an asJava method that implicitly converts a Scala mutable Set to a Java Set.

See also: mutableSetAsJavaSet

final def ne(arg0: AnyRef): Boolean

Equivalent to !(this eq that).

returns: true if the argument is not a reference to the receiver object; false otherwise.

Definition Classes: AnyRef

final def notify(): Unit

Wakes up a single thread that is waiting on the receiver object's monitor.

Definition Classes: AnyRef
Annotations: @native()
Note: not specified by SLS as a member of AnyRef

final def notifyAll(): Unit

Wakes up all threads that are waiting on the receiver object's monitor.

Definition Classes: AnyRef
Annotations: @native()
Note: not specified by SLS as a member of AnyRef

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

Adds an asScala method that implicitly converts a Java Properties to a Scala mutable Map[String, String].

See also: propertiesAsScalaMap

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

Adds an asJava method that implicitly converts a Scala Seq to a Java List.

See also: seqAsJavaList

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

Adds an asJava method that implicitly converts a Scala Set to a Java Set.

See also: setAsJavaSet

final def synchronized[T0](arg0: => T0): T0

Definition Classes: AnyRef

def toString(): String

Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

returns: a String representation of the object.

Definition Classes: AnyRef → Any

final def wait(): Unit

Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.InterruptedException])

final def wait(arg0: Long, arg1: Int): Unit

Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.InterruptedException])

final def wait(arg0: Long): Unit

Definition Classes: AnyRef
Annotations: @throws(classOf[java.lang.InterruptedException]) @native()

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.13.0/scala/collection/JavaConverters$.html