scala

package scala

Core Scala types. They are always available without an explicit import.

class AnyRef extends Any

Class AnyRef is the root class of all reference types . All types except the value types descend from this class.

Deprecated Value Members

object Responder extends Serializable

This object contains utility methods to build responders.

Type Members

type ::[A] = scala.collection.immutable.::[A]

type AbstractMethodError = java.lang.AbstractMethodError

abstract class Any

Class Any is the root of the Scala class hierarchy. Every class in a Scala execution environment inherits directly or indirectly from this class.

Starting with Scala 2.10 it is possible to directly extend Any using _ universal traits_ . A universal trait is a trait that extends Any , only has def s as members, and does no initialization.

The main use case for universal traits is to allow basic inheritance of methods for value classes. For example,

trait Printable extends Any {
  def print(): Unit = println(this)
}
class Wrapper(val underlying: Int) extends AnyVal with Printable

val w = new Wrapper(3)
w.print()

See the Value Classes and Universal Traits for more details on the interplay of universal traits and value classes.

abstract class AnyVal extends Any

AnyVal is the root class of all value types , which describe values not implemented as objects in the underlying host system. Value classes are specified in Scala Language Specification, section 12.2.

The standard implementation includes nine AnyVal subtypes:

scala.Double, scala.Float, scala.Long, scala.Int, scala.Char, scala.Short, and scala.Byte are the numeric value types .

scala.Unit and scala.Boolean are the non-numeric value types .

Other groupings:

  • The subrange types are scala.Byte, scala.Short, and scala.Char.
  • The integer types include the subrange types as well as scala.Int and scala.Long.
  • The floating point types are scala.Float and scala.Double.

Prior to Scala 2.10, AnyVal was a sealed trait. Beginning with Scala 2.10, however, it is possible to define a subclass of AnyVal called a user-defined value class which is treated specially by the compiler. Properly-defined user value classes provide a way to improve performance on user-defined types by avoiding object allocation at runtime, and by replacing virtual method invocations with static method invocations.

User-defined value classes which avoid object allocation…

  • must have a single val parameter that is the underlying runtime representation.
  • can define def s, but no val s, var s, or nested traits s, class es or object s.
  • typically extend no other trait apart from AnyVal .
  • cannot be used in type tests or pattern matching.
  • may not override equals or hashCode methods.

A minimal example:

class Wrapper(val underlying: Int) extends AnyVal {
  def foo: Wrapper = new Wrapper(underlying * 19)
}

It’s important to note that user-defined value classes are limited, and in some circumstances, still must allocate a value class instance at runtime. These limitations and circumstances are explained in greater detail in the Value Classes and Universal Traits.

trait App extends DelayedInit

The App trait can be used to quickly turn objects into executable programs. Here is an example:

object Main extends App {
  Console.println("Hello World: " + (args mkString ", "))
}

Here, object Main inherits the main method of App .

args returns the current command line arguments as an array.

Caveats

  • It should be noted that this trait is implemented using the DelayedInit functionality, which means that fields of the object will not have been initialized before the main method has been executed.*

It should also be noted that the main method should not be overridden: the whole class body becomes the “main method”.

Future versions of this trait will no longer extend DelayedInit .

final class Array[T] extends java.io.Serializable with java.lang.Cloneable

Arrays are mutable, indexed collections of values. Array[T] is Scala’s representation for Java’s T[] .

val numbers = Array(1, 2, 3, 4)
val first = numbers(0) // read the first element
numbers(3) = 100 // replace the 4th array element with 100
val biggerNumbers = numbers.map(_ * 2) // multiply all numbers by two

Arrays make use of two common pieces of Scala syntactic sugar, shown on lines 2 and 3 of the above example code. Line 2 is translated into a call to apply(Int) , while line 3 is translated into a call to update(Int, T) .

Two implicit conversions exist in scala.Predef that are frequently applied to arrays: a conversion to scala.collection.mutable.ArrayOps (shown on line 4 of the example above) and a conversion to scala.collection.mutable.WrappedArray (a subtype of scala.collection.Seq). Both types make available many of the standard operations found in the Scala collections API. The conversion to ArrayOps is temporary, as all operations defined on ArrayOps return an Array , while the conversion to WrappedArray is permanent as all operations return a WrappedArray .

The conversion to ArrayOps takes priority over the conversion to WrappedArray . For instance, consider the following code:

val arr = Array(1, 2, 3)
val arrReversed = arr.reverse
val seqReversed : Seq[Int] = arr.reverse

Value arrReversed will be of type Array[Int] , with an implicit conversion to ArrayOps occurring to perform the reverse operation. The value of seqReversed , on the other hand, will be computed by converting to WrappedArray first and invoking the variant of reverse that returns another WrappedArray .

type ArrayIndexOutOfBoundsException = java.lang.ArrayIndexOutOfBoundsException

type BigDecimal = scala.math.BigDecimal

type BigInt = scala.math.BigInt

abstract final class Boolean extends AnyVal

Boolean (equivalent to Java’s boolean primitive type) is a subtype of scala.AnyVal. Instances of Boolean are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Boolean => scala.runtime.RichBoolean which provides useful non-primitive operations.

type BufferedIterator[+A] = scala.collection.BufferedIterator[A]

abstract final class Byte extends AnyVal

Byte , a 8-bit signed integer (equivalent to Java’s byte primitive type) is a subtype of scala.AnyVal. Instances of Byte are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Byte => scala.runtime.RichByte which provides useful non-primitive operations.

abstract final class Char extends AnyVal

Char , a 16-bit unsigned integer (equivalent to Java’s char primitive type) is a subtype of scala.AnyVal. Instances of Char are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Char => scala.runtime.RichChar which provides useful non-primitive operations.

type ClassCastException = java.lang.ClassCastException

trait Cloneable extends java.lang.Cloneable

Classes extending this trait are cloneable across platforms (Java,.NET).

trait DelayedInit extends AnyRef

Classes and objects (but note, not traits) inheriting the DelayedInit marker trait will have their initialization code rewritten as follows: code becomes delayedInit(code) .

Initialization code comprises all statements and all value definitions that are executed during initialization.

Example:

trait Helper extends DelayedInit {
  def delayedInit(body: => Unit) = {
    println("dummy text, printed before initialization of C")
    body // evaluates the initialization code of C
  }
}

class C extends Helper {
  println("this is the initialization code of C")
}

object Test extends App {
  val c = new C
}

Should result in the following being printed:

dummy text, printed before initialization of C
this is the initialization code of C
  • Annotations
    • @ deprecated
  • Deprecated
    • (Since version 2.11.0) DelayedInit semantics can be surprising. Support for App will continue. See the release notes for more details: https://github.com/scala/scala/releases/tag/v2.11.0-RC1
  • Source
  • See also
    • “Delayed Initialization” subsection of the Scala Language Specification (section 5.1)

abstract final class Double extends AnyVal

Double , a 64-bit IEEE-754 floating point number (equivalent to Java’s double primitive type) is a subtype of scala.AnyVal. Instances of Double are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Double => scala.runtime.RichDouble which provides useful non-primitive operations.

trait Dynamic extends Any

A marker trait that enables dynamic invocations. Instances x of this trait allow method invocations x.meth(args) for arbitrary method names meth and argument lists args as well as field accesses x.field for arbitrary field names field .

If a call is not natively supported by x (i.e. if type checking fails), it is rewritten according to the following rules:

foo.method("blah")      ~~> foo.applyDynamic("method")("blah")
foo.method(x = "blah")  ~~> foo.applyDynamicNamed("method")(("x", "blah"))
foo.method(x = 1, 2)    ~~> foo.applyDynamicNamed("method")(("x", 1), ("", 2))
foo.field           ~~> foo.selectDynamic("field")
foo.varia = 10      ~~> foo.updateDynamic("varia")(10)
foo.arr(10) = 13    ~~> foo.selectDynamic("arr").update(10, 13)
foo.arr(10)         ~~> foo.applyDynamic("arr")(10)

As of Scala 2.10, defining direct or indirect subclasses of this trait is only possible if the language feature dynamics is enabled.

type Either[+A, +B] = scala.util.Either[A, B]

abstract class Enumeration extends Serializable

Defines a finite set of values specific to the enumeration. Typically these values enumerate all possible forms something can take and provide a lightweight alternative to case classes.

Each call to a Value method adds a new unique value to the enumeration. To be accessible, these values are usually defined as val members of the evaluation.

All values in an enumeration share a common, unique type defined as the Value type member of the enumeration ( Value selected on the stable identifier path of the enumeration instance).

Example:

object Main extends App {
  object WeekDay extends Enumeration {
    type WeekDay = Value
    val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value
  }
  import WeekDay._
  def isWorkingDay(d: WeekDay) = ! (d == Sat || d == Sun)
  WeekDay.values filter isWorkingDay foreach println
}
// output:
// Mon
// Tue
// Wed
// Thu
// Fri

trait Equals extends Any

An interface containing operations for equality. The only method not already present in class AnyRef is canEqual .

type Equiv[T] = scala.math.Equiv[T]

type Error = java.lang.Error

type Exception = java.lang.Exception

class FallbackArrayBuilding extends AnyRef

Contains a fallback builder for arrays when the element type does not have a class tag. In that case a generic array is built.

abstract final class Float extends AnyVal

Float , a 32-bit IEEE-754 floating point number (equivalent to Java’s float primitive type) is a subtype of scala.AnyVal. Instances of Float are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Float => scala.runtime.RichFloat which provides useful non-primitive operations.

type Fractional[T] = scala.math.Fractional[T]

trait Function0[+R] extends AnyRef

A function of 0 parameters.

In the following example, the definition of javaVersion is a shorthand for the anonymous class definition anonfun0:

object Main extends App {
   val javaVersion = () => sys.props("java.version")

   val anonfun0 = new Function0[String] {
     def apply(): String = sys.props("java.version")
   }
   assert(javaVersion() == anonfun0())
}

trait Function1[-T1, +R] extends AnyRef

A function of 1 parameter.

In the following example, the definition of succ is a shorthand for the anonymous class definition anonfun1:

object Main extends App {
   val succ = (x: Int) => x + 1
   val anonfun1 = new Function1[Int, Int] {
     def apply(x: Int): Int = x + 1
   }
   assert(succ(0) == anonfun1(0))
}

Note that the difference between Function1 and scala.PartialFunction is that the latter can specify inputs which it will not handle.

trait Function10[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, +R] extends AnyRef

A function of 10 parameters.

trait Function11[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, +R] extends AnyRef

A function of 11 parameters.

trait Function12[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, +R] extends AnyRef

A function of 12 parameters.

trait Function13[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, +R] extends AnyRef

A function of 13 parameters.

trait Function14[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, +R] extends AnyRef

A function of 14 parameters.

trait Function15[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, +R] extends AnyRef

A function of 15 parameters.

trait Function16[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, +R] extends AnyRef

A function of 16 parameters.

trait Function17[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, -T17, +R] extends AnyRef

A function of 17 parameters.

trait Function18[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, -T17, -T18, +R] extends AnyRef

A function of 18 parameters.

trait Function19[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, -T17, -T18, -T19, +R] extends AnyRef

A function of 19 parameters.

trait Function2[-T1, -T2, +R] extends AnyRef

A function of 2 parameters.

In the following example, the definition of max is a shorthand for the anonymous class definition anonfun2:

object Main extends App {
   val max = (x: Int, y: Int) => if (x < y) y else x

   val anonfun2 = new Function2[Int, Int, Int] {
     def apply(x: Int, y: Int): Int = if (x < y) y else x
   }
   assert(max(0, 1) == anonfun2(0, 1))
}

trait Function20[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, -T17, -T18, -T19, -T20, +R] extends AnyRef

A function of 20 parameters.

trait Function21[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, -T17, -T18, -T19, -T20, -T21, +R] extends AnyRef

A function of 21 parameters.

trait Function22[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, -T10, -T11, -T12, -T13, -T14, -T15, -T16, -T17, -T18, -T19, -T20, -T21, -T22, +R] extends AnyRef

A function of 22 parameters.

trait Function3[-T1, -T2, -T3, +R] extends AnyRef

A function of 3 parameters.

trait Function4[-T1, -T2, -T3, -T4, +R] extends AnyRef

A function of 4 parameters.

trait Function5[-T1, -T2, -T3, -T4, -T5, +R] extends AnyRef

A function of 5 parameters.

trait Function6[-T1, -T2, -T3, -T4, -T5, -T6, +R] extends AnyRef

A function of 6 parameters.

trait Function7[-T1, -T2, -T3, -T4, -T5, -T6, -T7, +R] extends AnyRef

A function of 7 parameters.

trait Function8[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, +R] extends AnyRef

A function of 8 parameters.

trait Function9[-T1, -T2, -T3, -T4, -T5, -T6, -T7, -T8, -T9, +R] extends AnyRef

A function of 9 parameters.

type IllegalArgumentException = java.lang.IllegalArgumentException

trait Immutable extends AnyRef

A marker trait for all immutable datastructures such as immutable collections.

type IndexOutOfBoundsException = java.lang.IndexOutOfBoundsException

type IndexedSeq[+A] = scala.collection.IndexedSeq[A]

abstract final class Int extends AnyVal

Int , a 32-bit signed integer (equivalent to Java’s int primitive type) is a subtype of scala.AnyVal. Instances of Int are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Int => scala.runtime.RichInt which provides useful non-primitive operations.

type Integral[T] = scala.math.Integral[T]

type InterruptedException = java.lang.InterruptedException

type Iterable[+A] = scala.collection.Iterable[A]

type Iterator[+A] = scala.collection.Iterator[A]

type Left[+A, +B] = scala.util.Left[A, B]

type List[+A] = scala.collection.immutable.List[A]

abstract final class Long extends AnyVal

Long , a 64-bit signed integer (equivalent to Java’s long primitive type) is a subtype of scala.AnyVal. Instances of Long are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Long => scala.runtime.RichLong which provides useful non-primitive operations.

final class MatchError extends RuntimeException

This class implements errors which are thrown whenever an object doesn’t match any pattern of a pattern matching expression.

trait Mutable extends AnyRef

A marker trait for mutable data structures such as mutable collections

type NoSuchElementException = java.util.NoSuchElementException

final class NotImplementedError extends Error

Throwing this exception can be a temporary replacement for a method body that remains to be implemented. For instance, the exception is thrown by Predef.??? .

trait NotNull extends Any

A marker trait for things that are not allowed to be null

abstract final class Nothing extends Any

Nothing is - together with scala.Null - at the bottom of Scala’s type hierarchy.

Nothing is a subtype of every other type (including scala.Null); there exist no instances of this type. Although type Nothing is uninhabited, it is nevertheless useful in several ways. For instance, the Scala library defines a value scala.collection.immutable.Nil of type List[Nothing] . Because lists are covariant in Scala, this makes scala.collection.immutable.Nil an instance of List[T] , for any element of type T .

Another usage for Nothing is the return type for methods which never return normally. One example is method error in scala.sys, which always throws an exception.

abstract final class Null extends AnyRef

Null is - together with scala.Nothing - at the bottom of the Scala type hierarchy.

Null is a subtype of all reference types; its only instance is the null reference. Since Null is not a subtype of value types, null is not a member of any such type. For instance, it is not possible to assign null to a variable of type scala.Int.

type NullPointerException = java.lang.NullPointerException

type NumberFormatException = java.lang.NumberFormatException

type Numeric[T] = scala.math.Numeric[T]

sealed abstract class Option[+A] extends Product with Serializable

Represents optional values. Instances of Option are either an instance of scala.Some or the object None .

The most idiomatic way to use an scala.Option instance is to treat it as a collection or monad and use map , flatMap , filter , or foreach :

val name: Option[String] = request getParameter "name"
val upper = name map { _.trim } filter { _.length != 0 } map { _.toUpperCase }
println(upper getOrElse "")

Note that this is equivalent to

val upper = for {
  name <- request getParameter "name"
  trimmed <- Some(name.trim)
  upper <- Some(trimmed.toUpperCase) if trimmed.length != 0
} yield upper
println(upper getOrElse "")

Because of how for comprehension works, if None is returned from request.getParameter , the entire expression results in None

This allows for sophisticated chaining of scala.Option values without having to check for the existence of a value.

A less-idiomatic way to use scala.Option values is via pattern matching:

val nameMaybe = request getParameter "name"
nameMaybe match {
  case Some(name) =>
    println(name.trim.toUppercase)
  case None =>
    println("No name value")
}
  • Self Type
    • Option [A]
  • Annotations
    • @ SerialVersionUID ()
  • Source
  • Version
    • 1.1, 16/01/2007
  • Note
    • Many of the methods in here are duplicative with those in the Traversable hierarchy, but they are duplicated for a reason: the implicit conversion tends to leave one with an Iterable in situations where one could have retained an Option.

type Ordered[T] = scala.math.Ordered[T]

type Ordering[T] = scala.math.Ordering[T]

trait PartialFunction[-A, +B] extends (A) ⇒ B

A partial function of type PartialFunction[A, B] is a unary function where the domain does not necessarily include all values of type A . The function isDefinedAt allows to test dynamically if a value is in the domain of the function.

Even if isDefinedAt returns true for an a: A , calling apply(a) may still throw an exception, so the following code is legal:

val f: PartialFunction[Int, Any] = { case _ => 1/0 }

It is the responsibility of the caller to call isDefinedAt before calling apply , because if isDefinedAt is false, it is not guaranteed apply will throw an exception to indicate an error condition. If an exception is not thrown, evaluation may result in an arbitrary value.

The main distinction between PartialFunction and scala.Function1 is that the user of a PartialFunction may choose to do something different with input that is declared to be outside its domain. For example:

val sample = 1 to 10
val isEven: PartialFunction[Int, String] = {
  case x if x % 2 == 0 => x+" is even"
}

// the method collect can use isDefinedAt to select which members to collect
val evenNumbers = sample collect isEven

val isOdd: PartialFunction[Int, String] = {
  case x if x % 2 == 1 => x+" is odd"
}

// the method orElse allows chaining another partial function to handle
// input outside the declared domain
val numbers = sample map (isEven orElse isOdd)

type PartialOrdering[T] = scala.math.PartialOrdering[T]

type PartiallyOrdered[T] = scala.math.PartiallyOrdered[T]

trait Product extends Equals

Base trait for all products, which in the standard library include at least scala.Product1 through scala.Product22 and therefore also their subclasses scala.Tuple1 through scala.Tuple22. In addition, all case classes implement Product with synthetically generated methods.

trait Product1[+T1] extends Product

Product1 is a cartesian product of 1 component.

trait Product10[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10] extends Product

Product10 is a cartesian product of 10 components.

trait Product11[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11] extends Product

Product11 is a cartesian product of 11 components.

trait Product12[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12] extends Product

Product12 is a cartesian product of 12 components.

trait Product13[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13] extends Product

Product13 is a cartesian product of 13 components.

trait Product14[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14] extends Product

Product14 is a cartesian product of 14 components.

trait Product15[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15] extends Product

Product15 is a cartesian product of 15 components.

trait Product16[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16] extends Product

Product16 is a cartesian product of 16 components.

trait Product17[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17] extends Product

Product17 is a cartesian product of 17 components.

trait Product18[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18] extends Product

Product18 is a cartesian product of 18 components.

trait Product19[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19] extends Product

Product19 is a cartesian product of 19 components.

trait Product2[+T1, +T2] extends Product

Product2 is a cartesian product of 2 components.

trait Product20[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19, +T20] extends Product

Product20 is a cartesian product of 20 components.

trait Product21[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19, +T20, +T21] extends Product

Product21 is a cartesian product of 21 components.

trait Product22[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19, +T20, +T21, +T22] extends Product

Product22 is a cartesian product of 22 components.

trait Product3[+T1, +T2, +T3] extends Product

Product3 is a cartesian product of 3 components.

trait Product4[+T1, +T2, +T3, +T4] extends Product

Product4 is a cartesian product of 4 components.

trait Product5[+T1, +T2, +T3, +T4, +T5] extends Product

Product5 is a cartesian product of 5 components.

trait Product6[+T1, +T2, +T3, +T4, +T5, +T6] extends Product

Product6 is a cartesian product of 6 components.

trait Product7[+T1, +T2, +T3, +T4, +T5, +T6, +T7] extends Product

Product7 is a cartesian product of 7 components.

trait Product8[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8] extends Product

Product8 is a cartesian product of 8 components.

trait Product9[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9] extends Product

Product9 is a cartesian product of 9 components.

trait Proxy extends Any

This class implements a simple proxy that forwards all calls to the public, non-final methods defined in class Any to another object self. Those methods are:

def hashCode(): Int
def equals(other: Any): Boolean
def toString(): String

Note: forwarding methods in this way will most likely create an asymmetric equals method, which is not generally recommended.

type Range = scala.collection.immutable.Range

abstract class Responder[+A] extends Serializable

Instances of responder are the building blocks of small programs written in continuation passing style. By using responder classes in for comprehensions, one can embed domain-specific languages in Scala while giving the impression that programs in these DSLs are written in direct style.

type Right[+A, +B] = scala.util.Right[A, B]

type RuntimeException = java.lang.RuntimeException

case class ScalaReflectionException(msg: String) extends Exception with Product with Serializable

An exception that indicates an error during Scala reflection

type Seq[+A] = scala.collection.Seq[A]

class SerialVersionUID extends Annotation with ClassfileAnnotation

Annotation for specifying the static SerialVersionUID field of a serializable class.

trait Serializable extends java.io.Serializable

Classes extending this trait are serializable across platforms (Java,.NET).

abstract final class Short extends AnyVal

Short , a 16-bit signed integer (equivalent to Java’s short primitive type) is a subtype of scala.AnyVal. Instances of Short are not represented by an object in the underlying runtime system.

There is an implicit conversion from scala.Short => scala.runtime.RichShort which provides useful non-primitive operations.

final case class Some[+A](x: A) extends Option[A] with Product with Serializable

Class Some[A] represents existing values of type A .

trait Specializable extends AnyRef

A common supertype for companions of specializable types. Should not be extended in user code.

type Stream[+A] = scala.collection.immutable.Stream[A]

type StringBuilder = scala.collection.mutable.StringBuilder

case class StringContext(parts: String*) extends Product with Serializable

This class provides the basic mechanism to do String Interpolation. String Interpolation allows users to embed variable references directly in processed string literals. Here’s an example:

val name = "James"
println(s"Hello, $name")  // Hello, James

Any processed string literal is rewritten as an instantiation and method call against this class. For example:

s"Hello, $name"

is rewritten to be:

StringContext("Hello, ", "").s(name)

By default, this class provides the raw , s and f methods as available interpolators.

To provide your own string interpolator, create an implicit class which adds a method to StringContext . Here’s an example:

implicit class JsonHelper(private val sc: StringContext) extends AnyVal {
  def json(args: Any*): JSONObject = ...
}
val x: JSONObject = json"{ a: $a }"

Here the JsonHelper extension class implicitly adds the json method to StringContext which can be used for json string literals.

type StringIndexOutOfBoundsException = java.lang.StringIndexOutOfBoundsException

final class Symbol extends Serializable

This class provides a simple way to get unique objects for equal strings. Since symbols are interned, they can be compared using reference equality. Instances of Symbol can be created easily with Scala’s built-in quote mechanism.

For instance, the Scala term 'mysym will invoke the constructor of the Symbol class in the following way: Symbol("mysym") .

type Throwable = java.lang.Throwable

type Traversable[+A] = scala.collection.Traversable[A]

type TraversableOnce[+A] = scala.collection.TraversableOnce[A]

case class Tuple1[+T1](_1: T1) extends Product1[T1] with Product with Serializable

A tuple of 1 elements; the canonical representation of a scala.Product1.

case class Tuple10[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10) extends Product10[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10] with Product with Serializable

A tuple of 10 elements; the canonical representation of a scala.Product10.

  • _1
    • Element 1 of this Tuple10
  • _2
    • Element 2 of this Tuple10
  • _3
    • Element 3 of this Tuple10
  • _4
    • Element 4 of this Tuple10
  • _5
    • Element 5 of this Tuple10
  • _6
    • Element 6 of this Tuple10
  • _7
    • Element 7 of this Tuple10
  • _8
    • Element 8 of this Tuple10
  • _9
    • Element 9 of this Tuple10
  • _10
    • Element 10 of this Tuple10
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple11[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11) extends Product11[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11] with Product with Serializable

A tuple of 11 elements; the canonical representation of a scala.Product11.

  • _1
    • Element 1 of this Tuple11
  • _2
    • Element 2 of this Tuple11
  • _3
    • Element 3 of this Tuple11
  • _4
    • Element 4 of this Tuple11
  • _5
    • Element 5 of this Tuple11
  • _6
    • Element 6 of this Tuple11
  • _7
    • Element 7 of this Tuple11
  • _8
    • Element 8 of this Tuple11
  • _9
    • Element 9 of this Tuple11
  • _10
    • Element 10 of this Tuple11
  • _11
    • Element 11 of this Tuple11
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple12[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12) extends Product12[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12] with Product with Serializable

A tuple of 12 elements; the canonical representation of a scala.Product12.

  • _1
    • Element 1 of this Tuple12
  • _2
    • Element 2 of this Tuple12
  • _3
    • Element 3 of this Tuple12
  • _4
    • Element 4 of this Tuple12
  • _5
    • Element 5 of this Tuple12
  • _6
    • Element 6 of this Tuple12
  • _7
    • Element 7 of this Tuple12
  • _8
    • Element 8 of this Tuple12
  • _9
    • Element 9 of this Tuple12
  • _10
    • Element 10 of this Tuple12
  • _11
    • Element 11 of this Tuple12
  • _12
    • Element 12 of this Tuple12
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple13[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13) extends Product13[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13] with Product with Serializable

A tuple of 13 elements; the canonical representation of a scala.Product13.

  • _1
    • Element 1 of this Tuple13
  • _2
    • Element 2 of this Tuple13
  • _3
    • Element 3 of this Tuple13
  • _4
    • Element 4 of this Tuple13
  • _5
    • Element 5 of this Tuple13
  • _6
    • Element 6 of this Tuple13
  • _7
    • Element 7 of this Tuple13
  • _8
    • Element 8 of this Tuple13
  • _9
    • Element 9 of this Tuple13
  • _10
    • Element 10 of this Tuple13
  • _11
    • Element 11 of this Tuple13
  • _12
    • Element 12 of this Tuple13
  • _13
    • Element 13 of this Tuple13
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple14[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14) extends Product14[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14] with Product with Serializable

A tuple of 14 elements; the canonical representation of a scala.Product14.

  • _1
    • Element 1 of this Tuple14
  • _2
    • Element 2 of this Tuple14
  • _3
    • Element 3 of this Tuple14
  • _4
    • Element 4 of this Tuple14
  • _5
    • Element 5 of this Tuple14
  • _6
    • Element 6 of this Tuple14
  • _7
    • Element 7 of this Tuple14
  • _8
    • Element 8 of this Tuple14
  • _9
    • Element 9 of this Tuple14
  • _10
    • Element 10 of this Tuple14
  • _11
    • Element 11 of this Tuple14
  • _12
    • Element 12 of this Tuple14
  • _13
    • Element 13 of this Tuple14
  • _14
    • Element 14 of this Tuple14
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple15[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15) extends Product15[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15] with Product with Serializable

A tuple of 15 elements; the canonical representation of a scala.Product15.

  • _1
    • Element 1 of this Tuple15
  • _2
    • Element 2 of this Tuple15
  • _3
    • Element 3 of this Tuple15
  • _4
    • Element 4 of this Tuple15
  • _5
    • Element 5 of this Tuple15
  • _6
    • Element 6 of this Tuple15
  • _7
    • Element 7 of this Tuple15
  • _8
    • Element 8 of this Tuple15
  • _9
    • Element 9 of this Tuple15
  • _10
    • Element 10 of this Tuple15
  • _11
    • Element 11 of this Tuple15
  • _12
    • Element 12 of this Tuple15
  • _13
    • Element 13 of this Tuple15
  • _14
    • Element 14 of this Tuple15
  • _15
    • Element 15 of this Tuple15
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple16[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16) extends Product16[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16] with Product with Serializable

A tuple of 16 elements; the canonical representation of a scala.Product16.

  • _1
    • Element 1 of this Tuple16
  • _2
    • Element 2 of this Tuple16
  • _3
    • Element 3 of this Tuple16
  • _4
    • Element 4 of this Tuple16
  • _5
    • Element 5 of this Tuple16
  • _6
    • Element 6 of this Tuple16
  • _7
    • Element 7 of this Tuple16
  • _8
    • Element 8 of this Tuple16
  • _9
    • Element 9 of this Tuple16
  • _10
    • Element 10 of this Tuple16
  • _11
    • Element 11 of this Tuple16
  • _12
    • Element 12 of this Tuple16
  • _13
    • Element 13 of this Tuple16
  • _14
    • Element 14 of this Tuple16
  • _15
    • Element 15 of this Tuple16
  • _16
    • Element 16 of this Tuple16
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple17[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16, _17: T17) extends Product17[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17] with Product with Serializable

A tuple of 17 elements; the canonical representation of a scala.Product17.

  • _1
    • Element 1 of this Tuple17
  • _2
    • Element 2 of this Tuple17
  • _3
    • Element 3 of this Tuple17
  • _4
    • Element 4 of this Tuple17
  • _5
    • Element 5 of this Tuple17
  • _6
    • Element 6 of this Tuple17
  • _7
    • Element 7 of this Tuple17
  • _8
    • Element 8 of this Tuple17
  • _9
    • Element 9 of this Tuple17
  • _10
    • Element 10 of this Tuple17
  • _11
    • Element 11 of this Tuple17
  • _12
    • Element 12 of this Tuple17
  • _13
    • Element 13 of this Tuple17
  • _14
    • Element 14 of this Tuple17
  • _15
    • Element 15 of this Tuple17
  • _16
    • Element 16 of this Tuple17
  • _17
    • Element 17 of this Tuple17
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple18[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16, _17: T17, _18: T18) extends Product18[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18] with Product with Serializable

A tuple of 18 elements; the canonical representation of a scala.Product18.

  • _1
    • Element 1 of this Tuple18
  • _2
    • Element 2 of this Tuple18
  • _3
    • Element 3 of this Tuple18
  • _4
    • Element 4 of this Tuple18
  • _5
    • Element 5 of this Tuple18
  • _6
    • Element 6 of this Tuple18
  • _7
    • Element 7 of this Tuple18
  • _8
    • Element 8 of this Tuple18
  • _9
    • Element 9 of this Tuple18
  • _10
    • Element 10 of this Tuple18
  • _11
    • Element 11 of this Tuple18
  • _12
    • Element 12 of this Tuple18
  • _13
    • Element 13 of this Tuple18
  • _14
    • Element 14 of this Tuple18
  • _15
    • Element 15 of this Tuple18
  • _16
    • Element 16 of this Tuple18
  • _17
    • Element 17 of this Tuple18
  • _18
    • Element 18 of this Tuple18
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple19[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16, _17: T17, _18: T18, _19: T19) extends Product19[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19] with Product with Serializable

A tuple of 19 elements; the canonical representation of a scala.Product19.

  • _1
    • Element 1 of this Tuple19
  • _2
    • Element 2 of this Tuple19
  • _3
    • Element 3 of this Tuple19
  • _4
    • Element 4 of this Tuple19
  • _5
    • Element 5 of this Tuple19
  • _6
    • Element 6 of this Tuple19
  • _7
    • Element 7 of this Tuple19
  • _8
    • Element 8 of this Tuple19
  • _9
    • Element 9 of this Tuple19
  • _10
    • Element 10 of this Tuple19
  • _11
    • Element 11 of this Tuple19
  • _12
    • Element 12 of this Tuple19
  • _13
    • Element 13 of this Tuple19
  • _14
    • Element 14 of this Tuple19
  • _15
    • Element 15 of this Tuple19
  • _16
    • Element 16 of this Tuple19
  • _17
    • Element 17 of this Tuple19
  • _18
    • Element 18 of this Tuple19
  • _19
    • Element 19 of this Tuple19
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple2[+T1, +T2](_1: T1, _2: T2) extends Product2[T1, T2] with Product with Serializable

A tuple of 2 elements; the canonical representation of a scala.Product2.

case class Tuple20[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19, +T20](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16, _17: T17, _18: T18, _19: T19, _20: T20) extends Product20[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20] with Product with Serializable

A tuple of 20 elements; the canonical representation of a scala.Product20.

  • _1
    • Element 1 of this Tuple20
  • _2
    • Element 2 of this Tuple20
  • _3
    • Element 3 of this Tuple20
  • _4
    • Element 4 of this Tuple20
  • _5
    • Element 5 of this Tuple20
  • _6
    • Element 6 of this Tuple20
  • _7
    • Element 7 of this Tuple20
  • _8
    • Element 8 of this Tuple20
  • _9
    • Element 9 of this Tuple20
  • _10
    • Element 10 of this Tuple20
  • _11
    • Element 11 of this Tuple20
  • _12
    • Element 12 of this Tuple20
  • _13
    • Element 13 of this Tuple20
  • _14
    • Element 14 of this Tuple20
  • _15
    • Element 15 of this Tuple20
  • _16
    • Element 16 of this Tuple20
  • _17
    • Element 17 of this Tuple20
  • _18
    • Element 18 of this Tuple20
  • _19
    • Element 19 of this Tuple20
  • _20
    • Element 20 of this Tuple20
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple21[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19, +T20, +T21](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16, _17: T17, _18: T18, _19: T19, _20: T20, _21: T21) extends Product21[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21] with Product with Serializable

A tuple of 21 elements; the canonical representation of a scala.Product21.

  • _1
    • Element 1 of this Tuple21
  • _2
    • Element 2 of this Tuple21
  • _3
    • Element 3 of this Tuple21
  • _4
    • Element 4 of this Tuple21
  • _5
    • Element 5 of this Tuple21
  • _6
    • Element 6 of this Tuple21
  • _7
    • Element 7 of this Tuple21
  • _8
    • Element 8 of this Tuple21
  • _9
    • Element 9 of this Tuple21
  • _10
    • Element 10 of this Tuple21
  • _11
    • Element 11 of this Tuple21
  • _12
    • Element 12 of this Tuple21
  • _13
    • Element 13 of this Tuple21
  • _14
    • Element 14 of this Tuple21
  • _15
    • Element 15 of this Tuple21
  • _16
    • Element 16 of this Tuple21
  • _17
    • Element 17 of this Tuple21
  • _18
    • Element 18 of this Tuple21
  • _19
    • Element 19 of this Tuple21
  • _20
    • Element 20 of this Tuple21
  • _21
    • Element 21 of this Tuple21
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple22[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9, +T10, +T11, +T12, +T13, +T14, +T15, +T16, +T17, +T18, +T19, +T20, +T21, +T22](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9, _10: T10, _11: T11, _12: T12, _13: T13, _14: T14, _15: T15, _16: T16, _17: T17, _18: T18, _19: T19, _20: T20, _21: T21, _22: T22) extends Product22[T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16, T17, T18, T19, T20, T21, T22] with Product with Serializable

A tuple of 22 elements; the canonical representation of a scala.Product22.

  • _1
    • Element 1 of this Tuple22
  • _2
    • Element 2 of this Tuple22
  • _3
    • Element 3 of this Tuple22
  • _4
    • Element 4 of this Tuple22
  • _5
    • Element 5 of this Tuple22
  • _6
    • Element 6 of this Tuple22
  • _7
    • Element 7 of this Tuple22
  • _8
    • Element 8 of this Tuple22
  • _9
    • Element 9 of this Tuple22
  • _10
    • Element 10 of this Tuple22
  • _11
    • Element 11 of this Tuple22
  • _12
    • Element 12 of this Tuple22
  • _13
    • Element 13 of this Tuple22
  • _14
    • Element 14 of this Tuple22
  • _15
    • Element 15 of this Tuple22
  • _16
    • Element 16 of this Tuple22
  • _17
    • Element 17 of this Tuple22
  • _18
    • Element 18 of this Tuple22
  • _19
    • Element 19 of this Tuple22
  • _20
    • Element 20 of this Tuple22
  • _21
    • Element 21 of this Tuple22
  • _22
    • Element 22 of this Tuple22
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple3[+T1, +T2, +T3](_1: T1, _2: T2, _3: T3) extends Product3[T1, T2, T3] with Product with Serializable

A tuple of 3 elements; the canonical representation of a scala.Product3.

case class Tuple4[+T1, +T2, +T3, +T4](_1: T1, _2: T2, _3: T3, _4: T4) extends Product4[T1, T2, T3, T4] with Product with Serializable

A tuple of 4 elements; the canonical representation of a scala.Product4.

  • _1
    • Element 1 of this Tuple4
  • _2
    • Element 2 of this Tuple4
  • _3
    • Element 3 of this Tuple4
  • _4
    • Element 4 of this Tuple4
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple5[+T1, +T2, +T3, +T4, +T5](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5) extends Product5[T1, T2, T3, T4, T5] with Product with Serializable

A tuple of 5 elements; the canonical representation of a scala.Product5.

  • _1
    • Element 1 of this Tuple5
  • _2
    • Element 2 of this Tuple5
  • _3
    • Element 3 of this Tuple5
  • _4
    • Element 4 of this Tuple5
  • _5
    • Element 5 of this Tuple5
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple6[+T1, +T2, +T3, +T4, +T5, +T6](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6) extends Product6[T1, T2, T3, T4, T5, T6] with Product with Serializable

A tuple of 6 elements; the canonical representation of a scala.Product6.

  • _1
    • Element 1 of this Tuple6
  • _2
    • Element 2 of this Tuple6
  • _3
    • Element 3 of this Tuple6
  • _4
    • Element 4 of this Tuple6
  • _5
    • Element 5 of this Tuple6
  • _6
    • Element 6 of this Tuple6
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple7[+T1, +T2, +T3, +T4, +T5, +T6, +T7](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7) extends Product7[T1, T2, T3, T4, T5, T6, T7] with Product with Serializable

A tuple of 7 elements; the canonical representation of a scala.Product7.

  • _1
    • Element 1 of this Tuple7
  • _2
    • Element 2 of this Tuple7
  • _3
    • Element 3 of this Tuple7
  • _4
    • Element 4 of this Tuple7
  • _5
    • Element 5 of this Tuple7
  • _6
    • Element 6 of this Tuple7
  • _7
    • Element 7 of this Tuple7
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple8[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8) extends Product8[T1, T2, T3, T4, T5, T6, T7, T8] with Product with Serializable

A tuple of 8 elements; the canonical representation of a scala.Product8.

  • _1
    • Element 1 of this Tuple8
  • _2
    • Element 2 of this Tuple8
  • _3
    • Element 3 of this Tuple8
  • _4
    • Element 4 of this Tuple8
  • _5
    • Element 5 of this Tuple8
  • _6
    • Element 6 of this Tuple8
  • _7
    • Element 7 of this Tuple8
  • _8
    • Element 8 of this Tuple8
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

case class Tuple9[+T1, +T2, +T3, +T4, +T5, +T6, +T7, +T8, +T9](_1: T1, _2: T2, _3: T3, _4: T4, _5: T5, _6: T6, _7: T7, _8: T8, _9: T9) extends Product9[T1, T2, T3, T4, T5, T6, T7, T8, T9] with Product with Serializable

A tuple of 9 elements; the canonical representation of a scala.Product9.

  • _1
    • Element 1 of this Tuple9
  • _2
    • Element 2 of this Tuple9
  • _3
    • Element 3 of this Tuple9
  • _4
    • Element 4 of this Tuple9
  • _5
    • Element 5 of this Tuple9
  • _6
    • Element 6 of this Tuple9
  • _7
    • Element 7 of this Tuple9
  • _8
    • Element 8 of this Tuple9
  • _9
    • Element 9 of this Tuple9
  • Annotations
    • @ deprecatedInheritance (message =…, since = “2.11.0”)
  • Source

final class UninitializedError extends RuntimeException

This class represents uninitialized variable/value errors.

final case class UninitializedFieldError(msg: String) extends RuntimeException with Product with Serializable

This class implements errors which are thrown whenever a field is used before it has been initialized.

Such runtime checks are not emitted by default. They can be enabled by the -Xcheckinit compiler option.

abstract final class Unit extends AnyVal

Unit is a subtype of scala.AnyVal. There is only one value of type Unit , () , and it is not represented by any object in the underlying runtime system. A method with return type Unit is analogous to a Java method which is declared void .

type UnsupportedOperationException = java.lang.UnsupportedOperationException

type Vector[+A] = scala.collection.immutable.Vector[A]

class deprecated extends Annotation with StaticAnnotation

An annotation that designates that a definition is deprecated. Access to the member then generates a deprecated warning.

class deprecatedInheritance extends Annotation with StaticAnnotation

An annotation that designates that inheriting from a class is deprecated.

This is usually done to warn about a non-final class being made final in a future version. Sub-classing such a class then generates a warning. No warnings are generated if the subclass is in the same compilation unit.

class deprecatedName extends Annotation with StaticAnnotation

An annotation that designates the name of the parameter to which it is applied as deprecated. Using that name in a named argument generates a deprecation warning.

For instance, evaluating the code below in the Scala interpreter

def inc(x: Int, @deprecatedName('y) n: Int): Int = x + n
inc(1, y = 2)

will produce the following output:

warning: there were 1 deprecation warnings; re-run with -deprecation for details
res0: Int = 3

class deprecatedOverriding extends Annotation with StaticAnnotation

An annotation that designates that overriding a member is deprecated.

Overriding such a member in a sub-class then generates a warning.

class inline extends Annotation with StaticAnnotation

An annotation on methods that requests that the compiler should try especially hard to inline the annotated method. The annotation can be used at definition site or at callsite.

@inline   final def f1(x: Int) = x
@noinline final def f2(x: Int) = x
          final def f3(x: Int) = x

 def t1 = f1(1)              // inlined if possible
 def t2 = f2(1)              // not inlined
 def t3 = f3(1)              // may be inlined (heuristics)
 def t4 = f1(1): @noinline   // not inlined (override at callsite)
 def t5 = f2(1): @inline     // not inlined (cannot override the @noinline at f2's definition)
 def t6 = f3(1): @inline     // inlined if possible
 def t7 = f3(1): @noinline   // not inlined
}

Note: parentheses are required when annotating a callsite withing a larger expression.

def t1 = f1(1) + f1(1): @noinline   // equivalent to (f1(1) + f1(1)): @noinline
def t2 = f1(1) + (f1(1): @noinline) // the second call to f1 is not inlined

class native extends Annotation with StaticAnnotation

Marker for native methods.

@native def f(x: Int, y: List[Long]): String = ...

Method body is not generated if method is marked with @native , but it is type checked when present.

class noinline extends Annotation with StaticAnnotation

An annotation on methods that forbids the compiler to inline the method, no matter how safe the inlining appears to be. The annotation can be used at definition site or at callsite.

@inline   final def f1(x: Int) = x
@noinline final def f2(x: Int) = x
          final def f3(x: Int) = x

 def t1 = f1(1)              // inlined if possible
 def t2 = f2(1)              // not inlined
 def t3 = f3(1)              // may be inlined (heuristics)
 def t4 = f1(1): @noinline   // not inlined (override at callsite)
 def t5 = f2(1): @inline     // not inlined (cannot override the @noinline at f2's definition)
 def t6 = f3(1): @inline     // inlined if possible
 def t7 = f3(1): @noinline   // not inlined
}

Note: parentheses are required when annotating a callsite withing a larger expression.

def t1 = f1(1) + f1(1): @noinline   // equivalent to (f1(1) + f1(1)): @noinline
def t2 = f1(1) + (f1(1): @noinline) // the second call to f1 is not inlined

class remote extends Annotation with StaticAnnotation

An annotation that designates the class to which it is applied as remotable.

For instance, the Scala code

@remote trait Hello {
  def sayHello(): String
}

is equivalent to the following Java code:

public interface Hello extends java.rmi.Remote {
    String sayHello() throws java.rmi.RemoteException;
}

class specialized extends Annotation with StaticAnnotation

Annotate type parameters on which code should be automatically specialized. For example:

class MyList[@specialized T] ...

Type T can be specialized on a subset of the primitive types by specifying a list of primitive types to specialize at:

class MyList[@specialized(Int, Double, Boolean) T] ..

class throws[T <: Throwable] extends Annotation with StaticAnnotation

Annotation for specifying the exceptions thrown by a method. For example:

class Reader(fname: String) {
  private val in = new BufferedReader(new FileReader(fname))
  @throws[IOException]("if the file doesn't exist")
  def read() = in.read()
}

class transient extends Annotation with StaticAnnotation

class unchecked extends Annotation

An annotation to designate that the annotated entity should not be considered for additional compiler checks. Specific applications include annotating the subject of a match expression to suppress exhaustiveness warnings, and annotating a type argument in a match case to suppress unchecked warnings.

Such suppression should be used with caution, without which one may encounter scala.MatchError or java.lang.ClassCastException at runtime. In most cases one can and should address the warning instead of suppressing it.

scala object Test extends App { // This would normally warn "match is not exhaustive" // because `None` is not covered. def f(x: Option[String]) = (x: @unchecked) match { case Some(y) => y } // This would normally warn "type pattern is unchecked" // but here will blindly cast the head element to String. def g(xs: Any) = xs match { case x: List[String @unchecked] => x.head } }

class volatile extends Annotation with StaticAnnotation

Value Members

object Array extends FallbackArrayBuilding with Serializable

Utility methods for operating on arrays. For example:

val a = Array(1, 2)
val b = Array.ofDim[Int](2)
val c = Array.concat(a, b)

where the array objects a , b and c have respectively the values Array(1, 2) , Array(0, 0) and Array(1, 2, 0, 0) .

object Boolean extends AnyValCompanion

object Byte extends AnyValCompanion

object Char extends AnyValCompanion

object Console extends DeprecatedConsole with AnsiColor

Implements functionality for printing Scala values on the terminal as well as reading specific values. Also defines constants for marking up text on ANSI terminals.

object Double extends AnyValCompanion

object Float extends AnyValCompanion

object Function

A module defining utility methods for higher-order functional programming.

object Int extends AnyValCompanion

object Long extends AnyValCompanion

object None extends Option[Nothing] with Product with Serializable

This case object represents non-existent values.

object Option extends Serializable

object PartialFunction

A few handy operations which leverage the extra bit of information available in partial functions. Examples:

import PartialFunction._

def strangeConditional(other: Any): Boolean = cond(other) {
  case x: String if x == "abc" || x == "def"  => true
  case x: Int => true
}
def onlyInt(v: Any): Option[Int] = condOpt(v) { case x: Int => x }

object Predef extends LowPriorityImplicits with DeprecatedPredef

The Predef object provides definitions that are accessible in all Scala compilation units without explicit qualification.

Commonly Used Types

Predef provides type aliases for types which are commonly used, such as the immutable collection types scala.collection.immutable.Map, scala.collection.immutable.Set, and the scala.collection.immutable.List constructors (scala.collection.immutable.:: and scala.collection.immutable.Nil).

Console I/O

Predef provides a number of simple functions for console I/O, such as print , println , readLine , readInt , etc. These functions are all aliases of the functions provided by scala.Console.

Assertions

A set of assert functions are provided for use as a way to document and dynamically check invariants in code. Invocations of assert can be elided at compile time by providing the command line option -Xdisable-assertions , which raises -Xelide-below above elidable.ASSERTION , to the scalac command.

Variants of assert intended for use with static analysis tools are also provided: assume , require and ensuring . require and ensuring are intended for use as a means of design-by-contract style specification of pre- and post-conditions on functions, with the intention that these specifications could be consumed by a static analysis tool. For instance,

def addNaturals(nats: List[Int]): Int = {
  require(nats forall (_ >= 0), "List contains negative numbers")
  nats.foldLeft(0)(_ + _)
} ensuring(_ >= 0)

The declaration of addNaturals states that the list of integers passed should only contain natural numbers (i.e. non-negative), and that the result returned will also be natural. require is distinct from assert in that if the condition fails, then the caller of the function is to blame rather than a logical error having been made within addNaturals itself. ensuring is a form of assert that declares the guarantee the function is providing with regards to its return value.

Implicit Conversions

A number of commonly applied implicit conversions are also defined here, and in the parent type scala.LowPriorityImplicits. Implicit conversions are provided for the “widening” of numeric values, for instance, converting a Short value to a Long value as required, and to add additional higher-order functions to Array values. These are described in more detail in the documentation of scala.Array.

object Product1

object Product10

object Product11

object Product12

object Product13

object Product14

object Product15

object Product16

object Product17

object Product18

object Product19

object Product2

object Product20

object Product21

object Product22

object Product3

object Product4

object Product5

object Product6

object Product7

object Product8

object Product9

object Proxy

object Short extends AnyValCompanion

object Specializable

object StringContext extends Serializable

object Symbol extends UniquenessCache[String, Symbol] with Serializable

object Unit extends AnyValCompanion

package annotation

package beans

package collection

Contains the base traits and objects needed to use and extend Scala’s collection library.

Guide

A detailed guide for using the collections library is available at http://docs.scala-lang.org/overviews/collections/introduction.html. Developers looking to extend the collections library can find a description of its architecture at http://docs.scala-lang.org/overviews/core/architecture-of-scala-collections.html.

Using Collections

It is convenient to treat all collections as either a scala.collection.Traversable or scala.collection.Iterable, as these traits define the vast majority of operations on a collection.

Collections can, of course, be treated as specifically as needed, and the library is designed to ensure that the methods that transform collections will return a collection of the same type:

scala> val array = Array(1,2,3,4,5,6)
array: Array[Int] = Array(1, 2, 3, 4, 5, 6)

scala> array map { _.toString }
res0: Array[String] = Array(1, 2, 3, 4, 5, 6)

scala> val list = List(1,2,3,4,5,6)
list: List[Int] = List(1, 2, 3, 4, 5, 6)

scala> list map { _.toString }
res1: List[String] = List(1, 2, 3, 4, 5, 6)

Creating Collections

The most common way to create a collection is to use its companion object as a factory. The three most commonly used collections are scala.collection.Seq, scala.collection.immutable.Set, and scala.collection.immutable.Map. They can be used directly as shown below since their companion objects are all available as type aliases in either the scala package or in scala.Predef . New collections are created like this:

scala> val seq = Seq(1,2,3,4,1)
seq: Seq[Int] = List(1, 2, 3, 4, 1)

scala> val set = Set(1,2,3,4,1)
set: scala.collection.immutable.Set[Int] = Set(1, 2, 3, 4)

scala> val map = Map(1 -> "one", 2 -> "two", 3 -> "three", 2 -> "too")
map: scala.collection.immutable.Map[Int,String] = Map(1 -> one, 2 -> too, 3 -> three)

It is also typical to prefer the scala.collection.immutable collections over those in scala.collection.mutable; the types aliased in the scala.Predef object are the immutable versions.

Also note that the collections library was carefully designed to include several implementations of each of the three basic collection types. These implementations have specific performance characteristics which are described in the guide.

The concrete parallel collections also have specific performance characteristics which are described in the parallel collections guide

Converting between Java Collections

The scala.collection.JavaConversions object provides implicit defs that will allow mostly seamless integration between APIs using Java Collections and the Scala collections library.

Alternatively the scala.collection.JavaConverters object provides a collection of decorators that allow converting between Scala and Java collections using asScala and asJava methods.

package compat

package concurrent

This package object contains primitives for concurrent and parallel programming.

Guide

A more detailed guide to Futures and Promises, including discussion and examples can be found at http://docs.scala-lang.org/overviews/core/futures.html.

Common Imports

When working with Futures, you will often find that importing the whole concurrent package is convenient, furthermore you are likely to need an implicit ExecutionContext in scope for many operations involving Futures and Promises:

import scala.concurrent._
import ExecutionContext.Implicits.global

Specifying Durations

Operations often require a duration to be specified. A duration DSL is available to make defining these easier:

import scala.concurrent.duration._
val d: Duration = 10.seconds

Using Futures For Non-blocking Computation

Basic use of futures is easy with the factory method on Future, which executes a provided function asynchronously, handing you back a future result of that function without blocking the current thread. In order to create the Future you will need either an implicit or explicit ExecutionContext to be provided:

import scala.concurrent._
import ExecutionContext.Implicits.global  // implicit execution context

val firstZebra: Future[Int] = Future {
  val source = scala.io.Source.fromFile("/etc/dictionaries-common/words")
  source.toSeq.indexOfSlice("zebra")
}

Avoid Blocking

Although blocking is possible in order to await results (with a mandatory timeout duration):

import scala.concurrent.duration._
Await.result(firstZebra, 10.seconds)

and although this is sometimes necessary to do, in particular for testing purposes, blocking in general is discouraged when working with Futures and concurrency in order to avoid potential deadlocks and improve performance. Instead, use callbacks or combinators to remain in the future domain:

val animalRange: Future[Int] = for {
  aardvark <- firstAardvark
  zebra <- firstZebra
} yield zebra - aardvark

animalRange.onSuccess {
  case x if x > 500000 => println("It's a long way from Aardvark to Zebra")
}

package io

object language

The scala.language object controls the language features available to the programmer, as proposed in the SIP-18 document.

Each of these features has to be explicitly imported into the current scope to become available:

import language.postfixOps // or language._
List(1, 2, 3) reverse

The language features are:

  • dynamics enables defining calls rewriting using the Dynamic trait
  • postfixOps enables postfix operators
  • reflectiveCalls enables using structural types
  • implicitConversions enables defining implicit methods and members
  • higherKinds enables writing higher-kinded types
  • existentials enables writing existential types

  • experimental contains newer features that have not yet been tested in production

  • Source

object languageFeature

package math

The package object scala.math contains methods for performing basic numeric operations such as elementary exponential, logarithmic, root and trigonometric functions.

package ref

package reflect

package runtime

package sys

The package object scala.sys contains methods for reading and altering core aspects of the virtual machine as well as the world outside of it.

package text

package util

Value Members From scala

val AnyRef: Specializable

(defined at scala)

val +:: scala.collection.+:.type

(defined at scala)

val :+: scala.collection.:+.type

(defined at scala)

val ::: scala.collection.immutable.::.type

(defined at scala)

val BigDecimal: scala.math.BigDecimal.type

(defined at scala)

val BigInt: scala.math.BigInt.type

(defined at scala)

val Either: scala.util.Either.type

(defined at scala)

val Equiv: scala.math.Equiv.type

(defined at scala)

val Fractional: scala.math.Fractional.type

(defined at scala)

val IndexedSeq: scala.collection.IndexedSeq.type

(defined at scala)

val Integral: scala.math.Integral.type

(defined at scala)

val Iterable: scala.collection.Iterable.type

(defined at scala)

val Iterator: scala.collection.Iterator.type

(defined at scala)

val Left: scala.util.Left.type

(defined at scala)

val List: scala.collection.immutable.List.type

(defined at scala)

val Nil: scala.collection.immutable.Nil.type

(defined at scala)

val Numeric: scala.math.Numeric.type

(defined at scala)

val Ordered: scala.math.Ordered.type

(defined at scala)

val Ordering: scala.math.Ordering.type

(defined at scala)

val Range: scala.collection.immutable.Range.type

(defined at scala)

val Right: scala.util.Right.type

(defined at scala)

val Seq: scala.collection.Seq.type

(defined at scala)

val Stream: scala.collection.immutable.Stream.type

(defined at scala)

val StringBuilder: scala.collection.mutable.StringBuilder.type

(defined at scala)

val Traversable: scala.collection.Traversable.type

(defined at scala)

val Vector: scala.collection.immutable.Vector.type

(defined at scala)

Value Members From scala

val #::: scala.collection.immutable.Stream.#::.type

(defined at scala#)

Full Source:

/*                     __                                               *\
**     ________ ___   / /  ___     Scala API                            **
**    / __/ __// _ | / /  / _ |    (c) 2003-2013, LAMP/EPFL             **
**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
** /____/\___/_/ |_/____/_/ | |                                         **
**                          |/                                          **
\*                                                                      */


/**
 * Core Scala types. They are always available without an explicit import.
 * @contentDiagram hideNodes "scala.Serializable"
 */
package object scala {
  type Throwable = java.lang.Throwable
  type Exception = java.lang.Exception
  type Error     = java.lang.Error

  type RuntimeException                = java.lang.RuntimeException
  type NullPointerException            = java.lang.NullPointerException
  type ClassCastException              = java.lang.ClassCastException
  type IndexOutOfBoundsException       = java.lang.IndexOutOfBoundsException
  type ArrayIndexOutOfBoundsException  = java.lang.ArrayIndexOutOfBoundsException
  type StringIndexOutOfBoundsException = java.lang.StringIndexOutOfBoundsException
  type UnsupportedOperationException   = java.lang.UnsupportedOperationException
  type IllegalArgumentException        = java.lang.IllegalArgumentException
  type NoSuchElementException          = java.util.NoSuchElementException
  type NumberFormatException           = java.lang.NumberFormatException
  type AbstractMethodError             = java.lang.AbstractMethodError
  type InterruptedException            = java.lang.InterruptedException

  // A dummy used by the specialization annotation.
  val AnyRef = new Specializable {
    override def toString = "object AnyRef"
  }

  type TraversableOnce[+A] = scala.collection.TraversableOnce[A]

  type Traversable[+A] = scala.collection.Traversable[A]
  val Traversable = scala.collection.Traversable

  type Iterable[+A] = scala.collection.Iterable[A]
  val Iterable = scala.collection.Iterable

  type Seq[+A] = scala.collection.Seq[A]
  val Seq = scala.collection.Seq

  type IndexedSeq[+A] = scala.collection.IndexedSeq[A]
  val IndexedSeq = scala.collection.IndexedSeq

  type Iterator[+A] = scala.collection.Iterator[A]
  val Iterator = scala.collection.Iterator

  type BufferedIterator[+A] = scala.collection.BufferedIterator[A]

  type List[+A] = scala.collection.immutable.List[A]
  val List = scala.collection.immutable.List

  val Nil = scala.collection.immutable.Nil

  type ::[A] = scala.collection.immutable.::[A]
  val :: = scala.collection.immutable.::

  val +: = scala.collection.+:
  val :+ = scala.collection.:+

  type Stream[+A] = scala.collection.immutable.Stream[A]
  val Stream = scala.collection.immutable.Stream
  val #:: = scala.collection.immutable.Stream.#::

  type Vector[+A] = scala.collection.immutable.Vector[A]
  val Vector = scala.collection.immutable.Vector

  type StringBuilder = scala.collection.mutable.StringBuilder
  val StringBuilder = scala.collection.mutable.StringBuilder

  type Range = scala.collection.immutable.Range
  val Range = scala.collection.immutable.Range

  // Numeric types which were moved into scala.math.*

  type BigDecimal = scala.math.BigDecimal
  val BigDecimal = scala.math.BigDecimal

  type BigInt = scala.math.BigInt
  val BigInt = scala.math.BigInt

  type Equiv[T] = scala.math.Equiv[T]
  val Equiv = scala.math.Equiv

  type Fractional[T] = scala.math.Fractional[T]
  val Fractional = scala.math.Fractional

  type Integral[T] = scala.math.Integral[T]
  val Integral = scala.math.Integral

  type Numeric[T] = scala.math.Numeric[T]
  val Numeric = scala.math.Numeric

  type Ordered[T] = scala.math.Ordered[T]
  val Ordered = scala.math.Ordered

  type Ordering[T] = scala.math.Ordering[T]
  val Ordering = scala.math.Ordering

  type PartialOrdering[T] = scala.math.PartialOrdering[T]
  type PartiallyOrdered[T] = scala.math.PartiallyOrdered[T]

  type Either[+A, +B] = scala.util.Either[A, B]
  val Either = scala.util.Either

  type Left[+A, +B] = scala.util.Left[A, B]
  val Left = scala.util.Left

  type Right[+A, +B] = scala.util.Right[A, B]
  val Right = scala.util.Right

  // Annotations which we might move to annotation.*
/*
  type SerialVersionUID = annotation.SerialVersionUID
  type deprecated = annotation.deprecated
  type deprecatedName = annotation.deprecatedName
  type inline = annotation.inline
  type native = annotation.native
  type noinline = annotation.noinline
  type remote = annotation.remote
  type specialized = annotation.specialized
  type transient = annotation.transient
  type throws  = annotation.throws
  type unchecked = annotation.unchecked.unchecked
  type volatile = annotation.volatile
  */
}