Enumeration

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 parameters:

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

trait Serializable

class Object

trait Matchable

class Any

object RoundingMode.type

Enumeration

Type members

Classlikes

A class implementing the scala.Enumeration.Value type.

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

Source:: Enumeration.scala

The type of the enumerated values.

Source:: Enumeration.scala

An ordering by id for values of this set

Source:: Enumeration.scala

A class for sets of values.

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

Value parameters:

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

Source:: Enumeration.scala

Concrete methods

Creates a fresh value, part of this enumeration.

Source:: Enumeration.scala

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

Value parameters:

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

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

Value parameters:

name: A human-readable name for that value.

Returns:

Fresh value called name.

Source:

Enumeration.scala

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

Value parameters:

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: