Enumeration
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
- Known subtypes
-
object RoundingMode
- Self type
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 Valuetrait Serializabletrait Comparable[Value]class Objecttrait Matchableclass AnyShow all
The type of the enumerated values.
The type of the enumerated values.
Attributes
- Source
- Enumeration.scala
- Supertypes
- Known subtypes
-
class Val
An ordering by id for values of this set
An ordering by id for values of this set
Attributes
- Source
- Enumeration.scala
- Supertypes
-
trait PartialOrdering[Value]trait Serializabletrait Comparator[Value]class Objecttrait Matchableclass AnyShow 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 Serializableclass AbstractSet[Value]class AbstractSet[Value]trait Equalsclass AbstractIterable[Value]trait IterableOnce[Value]class Objecttrait Matchableclass AnyShow all
A factory object for value sets
A factory object for value sets
Attributes
- Companion
- class
- Source
- Enumeration.scala
- Supertypes
- Self type
-
ValueSet.type
Value members
Constructors
Attributes
- Source
- Enumeration.scala
Concrete methods
Creates a fresh value, part of this enumeration.
Creates a fresh value, part of this enumeration, identified by the integer i
.
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
.
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
.
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 namename
. - Source
- Enumeration.scala
The value of this enumeration with given id x
The one higher than the highest integer amongst those used to identify values in this enumeration.
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.
The values of this enumeration as a set.
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 thisEnumeration
if its name matchess
- Throws
-
NoSuchElementException if no
Value
with a matching name is in thisEnumeration
- Source
- Enumeration.scala
Concrete fields
The integer to use to identify the next created value.
The string to use to name the next created value.