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AnyVal

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:

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 defs, but no vals, vars, or nested traits, classes or objects.
  • 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.

Source
AnyVal.scala
Linear Supertypes
Any
Known Subclasses
UnapplySeqWrapper, Boolean, Byte, Char, Double, Float, UnliftOps, Int, Long, ElementWiseExtractor, ArrowAssoc, Ensuring, StringFormat, Short, Unit, ValueOf, ArrayOps, IterableOnceExtensionMethods, SizeCompareOps, UnapplySeqWrapper, Shape, StringOps, Deferrer, Partial, Deferrer, UnwrapOp, DoubleMult, DurationDouble, DurationInt, DurationLong, IntMult, LongMult, JavaDurationOps, ScalaDurationOps, RichBiConsumerAsFunction2, RichBiFunctionAsFunction2, RichBiPredicateAsFunction2, RichBinaryOperatorAsFunction2, RichBooleanSupplierAsFunction0, RichConsumerAsFunction1, RichDoubleBinaryOperatorAsFunction2, RichDoubleConsumerAsFunction1, RichDoubleFunctionAsFunction1, RichDoublePredicateAsFunction1, RichDoubleSupplierAsFunction0, RichDoubleToIntFunctionAsFunction1, RichDoubleToLongFunctionAsFunction1, RichDoubleUnaryOperatorAsFunction1, RichFunction0AsBooleanSupplier, RichFunction0AsDoubleSupplier, RichFunction0AsIntSupplier, RichFunction0AsLongSupplier, RichFunction0AsSupplier, RichFunction1AsConsumer, RichFunction1AsDoubleConsumer, RichFunction1AsDoubleFunction, RichFunction1AsDoublePredicate, RichFunction1AsDoubleToIntFunction, RichFunction1AsDoubleToLongFunction, RichFunction1AsDoubleUnaryOperator, RichFunction1AsFunction, RichFunction1AsIntConsumer, RichFunction1AsIntFunction, RichFunction1AsIntPredicate, RichFunction1AsIntToDoubleFunction, RichFunction1AsIntToLongFunction, RichFunction1AsIntUnaryOperator, RichFunction1AsLongConsumer, RichFunction1AsLongFunction, RichFunction1AsLongPredicate, RichFunction1AsLongToDoubleFunction, RichFunction1AsLongToIntFunction, RichFunction1AsLongUnaryOperator, RichFunction1AsPredicate, RichFunction1AsToDoubleFunction, RichFunction1AsToIntFunction, RichFunction1AsToLongFunction, RichFunction1AsUnaryOperator, RichFunction2AsBiConsumer, RichFunction2AsBiFunction, RichFunction2AsBiPredicate, RichFunction2AsBinaryOperator, RichFunction2AsDoubleBinaryOperator, RichFunction2AsIntBinaryOperator, RichFunction2AsLongBinaryOperator, RichFunction2AsObjDoubleConsumer, RichFunction2AsObjIntConsumer, RichFunction2AsObjLongConsumer, RichFunction2AsToDoubleBiFunction, RichFunction2AsToIntBiFunction, RichFunction2AsToLongBiFunction, RichFunctionAsFunction1, RichIntBinaryOperatorAsFunction2, RichIntConsumerAsFunction1, RichIntFunctionAsFunction1, RichIntPredicateAsFunction1, RichIntSupplierAsFunction0, RichIntToDoubleFunctionAsFunction1, RichIntToLongFunctionAsFunction1, RichIntUnaryOperatorAsFunction1, RichLongBinaryOperatorAsFunction2, RichLongConsumerAsFunction1, RichLongFunctionAsFunction1, RichLongPredicateAsFunction1, RichLongSupplierAsFunction0, RichLongToDoubleFunctionAsFunction1, RichLongToIntFunctionAsFunction1, RichLongUnaryOperatorAsFunction1, RichObjDoubleConsumerAsFunction2, RichObjIntConsumerAsFunction2, RichObjLongConsumerAsFunction2, RichPredicateAsFunction1, RichSupplierAsFunction0, RichToDoubleBiFunctionAsFunction2, RichToDoubleFunctionAsFunction1, RichToIntBiFunctionAsFunction2, RichToIntFunctionAsFunction1, RichToLongBiFunctionAsFunction2, RichToLongFunctionAsFunction1, RichUnaryOperatorAsFunction1, CompletionStageOps, FutureOps, RichOption, RichOptional, RichOptionalDouble, RichOptionalInt, RichOptionalLong, ChainingOps, MergeableEither, any2stringadd, SearchImpl
Type Hierarchy
Ordering
  1. Alphabetic
  2. By Inheritance
Inherited
  1. AnyVal
  2. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Visibility
  1. Public
  2. Protected

Instance Constructors

  1. new AnyVal()

Value Members

  1. final def !=(arg0: Any): Boolean

    Test two objects for inequality.

    Test two objects for inequality.

    returns

    true if !(this == that), false otherwise.

    Definition Classes
    Any
  2. final def ##: Int

    Equivalent to x.hashCode except for boxed numeric types and null.

    Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

    returns

    a hash value consistent with ==

    Definition Classes
    Any
  3. def +(other: String): String
    Implicit
    This member is added by an implicit conversion from AnyVal toany2stringadd[AnyVal] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (AnyVal, B)
    Implicit
    This member is added by an implicit conversion from AnyVal toArrowAssoc[AnyVal] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean

    Test two objects for equality.

    Test two objects for equality. The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    Any
  6. final def asInstanceOf[T0]: T0

    Forces the compiler to treat the receiver object as having type T0, even though doing so may violate type safety.

    Forces the compiler to treat the receiver object as having type T0, even though doing so may violate type safety.

    This method is useful when you believe you have type information the compiler doesn't, and it also isn't possible to check the type at runtime. In such situations, skipping type safety is the only option.

    It is platform dependent whether asInstanceOf has any effect at runtime. It might do a runtime type test on the erasure of T0, insert a conversion (such as boxing/unboxing), fill in a default value, or do nothing at all.

    In particular, asInstanceOf is not a type test. It does **not** mean:

    this match {
 case x: T0 => x
 case _     => throw ClassCastException("...")

    Use pattern matching or isInstanceOf for type testing instead.

    Situations where asInstanceOf is useful:

    • when flow analysis fails to deduce T0 automatically
    • when down-casting a type parameter or an abstract type member (which cannot be checked at runtime due to type erasure) If there is any doubt and you are able to type test instead, you should do so.

    Be careful of using asInstanceOf when T0 is a primitive type. When T0 is primitive, asInstanceOf may insert a conversion instead of a type test. If your intent is to convert, use a toT method (x.toChar, x.toByte, etc.).

    returns

    the receiver object.

    Definition Classes
    Any
    Exceptions thrown

    ClassCastException if the receiver is not an instance of the erasure of T0, if that can be checked on this platform

  7. def ensuring(cond: (AnyVal) => Boolean, msg: => Any): AnyVal
    Implicit
    This member is added by an implicit conversion from AnyVal toEnsuring[AnyVal] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  8. def ensuring(cond: (AnyVal) => Boolean): AnyVal
    Implicit
    This member is added by an implicit conversion from AnyVal toEnsuring[AnyVal] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  9. def ensuring(cond: Boolean, msg: => Any): AnyVal
    Implicit
    This member is added by an implicit conversion from AnyVal toEnsuring[AnyVal] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: Boolean): AnyVal
    Implicit
    This member is added by an implicit conversion from AnyVal toEnsuring[AnyVal] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def equals(arg0: Any): Boolean

    Compares the receiver object (this) with the argument object (that) for equivalence.

    Compares the receiver object (this) with the argument object (that) for equivalence.

    Any implementation of this method should be an equivalence relation:

    • It is reflexive: for any instance x of type Any, x.equals(x) should return true.
    • It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true.
    • It is transitive: for any instances x, y, and z of type Any if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

    If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is usually necessary to override hashCode to ensure that objects which are "equal" (o1.equals(o2) returns true) hash to the same scala.Int. (o1.hashCode.equals(o2.hashCode)).

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    Definition Classes
    Any
  12. def getClass(): Class[_ <: AnyVal]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

    a class object corresponding to the runtime type of the receiver.

    Definition Classes
    AnyVal → Any
  13. def hashCode(): Int

    Calculate a hash code value for the object.

    Calculate a hash code value for the object.

    The default hashing algorithm is platform dependent.

    Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

    returns

    the hash code value for this object.

    Definition Classes
    Any
  14. final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object has the same erasure as T0.

    Test whether the dynamic type of the receiver object has the same erasure as T0.

    Depending on what T0 is, the test is done in one of the below ways:

    • T0 is a non-parameterized class type, e.g. BigDecimal: this method returns true if the value of the receiver object is a BigDecimal or a subtype of BigDecimal.
    • T0 is a parameterized class type, e.g. List[Int]: this method returns true if the value of the receiver object is some List[X] for any X. For example, List(1, 2, 3).isInstanceOf[List[String]] will return true.
    • T0 is some singleton type x.type or literal x: this method returns this.eq(x). For example, x.isInstanceOf[1] is equivalent to x.eq(1)
    • T0 is an intersection X with Y or X & Y: this method is equivalent to x.isInstanceOf[X] && x.isInstanceOf[Y]
    • T0 is a union X | Y: this method is equivalent to x.isInstanceOf[X] || x.isInstanceOf[Y]
    • T0 is a type parameter or an abstract type member: this method is equivalent to isInstanceOf[U] where U is T0's upper bound, Any if T0 is unbounded. For example, x.isInstanceOf[A] where A is an unbounded type parameter will return true for any value of x.

    This is exactly equivalent to the type pattern _: T0

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    Definition Classes
    Any
    Note

    due to the unexpectedness of List(1, 2, 3).isInstanceOf[List[String]] returning true and x.isInstanceOf[A] where A is a type parameter or abstract member returning true, these forms issue a warning.

  15. def toString(): String

    Returns a string representation of the object.

    Returns a string representation of the object.

    The default representation is platform dependent.

    returns

    a string representation of the object.

    Definition Classes
    Any

Deprecated Value Members

  1. def formatted(fmtstr: String): String

    Returns string formatted according to given format string.

    Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

    Implicit
    This member is added by an implicit conversion from AnyVal toStringFormat[AnyVal] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @deprecated @inline()
    Deprecated

    (Since version 2.12.16) Use formatString.format(value) instead of value.formatted(formatString), or use the f"" string interpolator. In Java 15 and later, formatted resolves to the new method in String which has reversed parameters.

  2. def →[B](y: B): (AnyVal, B)
    Implicit
    This member is added by an implicit conversion from AnyVal toArrowAssoc[AnyVal] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @deprecated
    Deprecated

    (Since version 2.13.0) Use -> instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.

Inherited from Any

Inherited by implicit conversion any2stringadd fromAnyVal to any2stringadd[AnyVal]

Inherited by implicit conversion StringFormat fromAnyVal to StringFormat[AnyVal]

Inherited by implicit conversion Ensuring fromAnyVal to Ensuring[AnyVal]

Inherited by implicit conversion ArrowAssoc fromAnyVal to ArrowAssoc[AnyVal]

Ungrouped