Enumeration

scala.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.

Attributes

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

Graph

Supertypes

trait Serializable

class Object

trait Matchable

class Any

Known subtypes

object RoundingMode.type

Self type

Enumeration

Members list

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.

Attributes

Source: Enumeration.scala
Supertypes: class Value

trait Serializable

trait Ordered[Value]

trait Comparable[Value]

class Object

trait Matchable

class Any
Show all

The type of the enumerated values.

Attributes

Source: Enumeration.scala
Supertypes: trait Serializable

trait Ordered[Value]

trait Comparable[Value]

class Object

trait Matchable

class Any
Show all
Known subtypes: class Val

An ordering by id for values of this set

Attributes

Source: Enumeration.scala
Supertypes: trait Ordering[Value]

trait PartialOrdering[Value]

trait Equiv[Value]

trait Serializable

trait Comparator[Value]

class Object

trait Matchable

class Any
Show all
Self type: ValueOrdering.type

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.

Attributes

Companion: object
Source: Enumeration.scala
Supertypes: trait Serializable

trait StrictOptimizedIterableOps[Value, Set, ValueSet]

trait SortedSet[Value]

trait SortedSetOps[Value, SortedSet, ValueSet]

trait SortedSet[Value]

trait SortedSetFactoryDefaults[Value, SortedSet, Set]

trait SortedSetOps[Value, SortedSet, ValueSet]

trait SortedOps[Value, ValueSet]

class AbstractSet[Value]

trait Set[Value]

trait SetOps[Value, Set, ValueSet]

trait Iterable[Value]

class AbstractSet[Value]

trait Set[Value]

trait Equals

trait SetOps[Value, Set, ValueSet]

trait Value => Boolean

class AbstractIterable[Value]

trait Iterable[Value]

trait IterableFactoryDefaults[Value, Set]

trait IterableOps[Value, Set, ValueSet]

trait IterableOnceOps[Value, Set, ValueSet]

trait IterableOnce[Value]

class Object

trait Matchable

class Any
Show all

A factory object for value sets

Attributes

Companion: class
Source: Enumeration.scala
Supertypes: trait SpecificIterableFactory[Value, ValueSet]

trait Factory[Value, ValueSet]

class Object

trait Matchable

class Any
Self type: ValueSet.type

Value members

Constructors

Attributes

Source: Enumeration.scala

Concrete methods

Creates a fresh value, part of this enumeration.

Attributes

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.

Attributes

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.

Attributes

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.

Attributes

Returns: Fresh value with the provided identifier i and name name.
Source: Enumeration.scala

The value of this enumeration with given id x

Attributes

Source: Enumeration.scala

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

Attributes

Source: Enumeration.scala

Attributes

Source: Enumeration.scala

The name of this enumeration.

Attributes

Definition Classes: Any
Source: Enumeration.scala

The values of this enumeration as a set.

Attributes

Source: Enumeration.scala

Return a Value from this Enumeration whose name matches the argument s.

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

Value parameters

s: an Enumeration name

Attributes

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

The integer to use to identify the next created value.

Attributes

Source: Enumeration.scala

The string to use to name the next created value.

Attributes

Source: Enumeration.scala

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