Enumeration

@SerialVersionUID(8476000850333817230L) abstract class Enumeration(initial: Int) 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 enumeration.

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).

Values SHOULD NOT be added to an enumeration after its construction; doing so makes the enumeration thread-unsafe. If values are added to an enumeration from multiple threads (in a non-synchronized fashion) after construction, the behavior of the enumeration is undefined.

Value Params
initial

The initial value from which to count the integers that identifies values at run-time.

Example

// Define a new enumeration with a type alias and work with the full set of enumerated values 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

// Example of adding attributes to an enumeration by extending the Enumeration.Val class object Planet extends Enumeration { protected case class PlanetVal(mass: Double, radius: Double) extends super.Val { def surfaceGravity: Double = Planet.G * mass / (radius * radius) def surfaceWeight(otherMass: Double): Double = otherMass * surfaceGravity } import scala.language.implicitConversions implicit def valueToPlanetVal(x: Value): PlanetVal = x.asInstanceOf[PlanetVal] val G: Double = 6.67300E-11 val Mercury = PlanetVal(3.303e+23, 2.4397e6) val Venus = PlanetVal(4.869e+24, 6.0518e6) val Earth = PlanetVal(5.976e+24, 6.37814e6) val Mars = PlanetVal(6.421e+23, 3.3972e6) val Jupiter = PlanetVal(1.9e+27, 7.1492e7) val Saturn = PlanetVal(5.688e+26, 6.0268e7) val Uranus = PlanetVal(8.686e+25, 2.5559e7) val Neptune = PlanetVal(1.024e+26, 2.4746e7) } println(Planet.values.filter(_.radius > 7.0e6)) // output: // Planet.ValueSet(Jupiter, Saturn, Uranus, Neptune)
Source
Enumeration.scala
class Object
trait Matchable
class Any

Type members

Classlikes

@SerialVersionUID(0.-(3501153230598116017L))
protected class Val(i: Int, name: String) extends Value with Serializable

A class implementing the scala.Enumeration.Value type. This class can be overridden to change the enumeration's naming and integer identification behaviour.

@SerialVersionUID(7091335633555234129L)
abstract class Value extends Ordered[Value] with Serializable

The type of the enumerated values.

object ValueOrdering extends Ordering[Value]

An ordering by id for values of this set

@SerialVersionUID(7229671200427364242L)

A class for sets of values. Iterating through this set will yield values in increasing order of their ids.

Value Params
nnIds

The set of ids of values (adjusted so that the lowest value does not fall below zero), organized as a BitSet.

Companion
object
Source
Enumeration.scala

A factory object for value sets

Companion
class
Source
Enumeration.scala

Value members

Constructors

Concrete methods

final protected def Value: Value

Creates a fresh value, part of this enumeration.

final protected def Value(i: Int): Value

Creates a fresh value, part of this enumeration, identified by the integer i.

Value Params
i

An integer that identifies this value at run-time. It must be unique amongst all values of the enumeration.

Returns

Fresh value identified by i.

Source
Enumeration.scala
final protected def Value(name: String): Value

Creates a fresh value, part of this enumeration, called name.

Value Params
name

A human-readable name for that value.

Returns

Fresh value called name.

Source
Enumeration.scala
final protected def Value(i: Int, name: String): Value

Creates a fresh value, part of this enumeration, called name and identified by the integer i.

Value Params
i

An integer that identifies this value at run-time. It must be unique amongst all values of the enumeration.

name

A human-readable name for that value.

Returns

Fresh value with the provided identifier i and name name.

Source
Enumeration.scala
final def apply(x: Int): Value

The value of this enumeration with given id x

final def maxId: Int

The one higher than the highest integer amongst those used to identify values in this enumeration.

protected def readResolve(): AnyRef
override def toString: String

The name of this enumeration.

Definition Classes
Any
Source
Enumeration.scala

The values of this enumeration as a set.

final def withName(s: String): Value

Return a Value from this Enumeration whose name matches the argument s. The names are determined automatically via reflection.

Value Params
s

an Enumeration name

Returns

the Value of this Enumeration if its name matches s

Throws
NoSuchElementException

if no Value with a matching name is in this Enumeration

Source
Enumeration.scala

Concrete fields

protected var nextId: Int

The integer to use to identify the next created value.

protected var nextName: Iterator[String]

The string to use to name the next created value.