sealed abstract class Duration extends Serializable with Ordered[Duration]
Utility for working with java.util.concurrent.TimeUnit durations.
This class is not meant as a general purpose representation of time, it is
optimized for the needs of scala.concurrent
.
Basic Usage
Examples:
import scala.concurrent.duration._ val duration = Duration(100, MILLISECONDS) val duration = Duration(100, "millis") duration.toNanos duration < 1.second duration <= Duration.Inf
Invoking inexpressible conversions (like calling toSeconds
on an infinite duration) will throw an IllegalArgumentException.
Implicits are also provided for Int, Long and Double. Example usage:
import scala.concurrent.duration._ val duration = 100.millis
The DSL provided by the implicit conversions always allows construction of finite durations, even for infinite Double inputs; use Duration.Inf instead.
Extractors, parsing and arithmetic are also included:
val d = Duration("1.2 µs") val Duration(length, unit) = 5 millis val d2 = d * 2.5 val d3 = d2 + 1.millisecond
Handling of Time Units
Calculations performed on finite durations always retain the more precise unit of either operand, no matter whether a coarser unit would be able to exactly express the same duration. This means that Duration can be used as a lossless container for a (length, unit) pair if it is constructed using the corresponding methods and no arithmetic is performed on it; adding/subtracting durations should in that case be done with care.
Correspondence to Double Semantics
The semantics of arithmetic operations on Duration are two-fold:
- exact addition/subtraction with nanosecond resolution for finite durations, independent of the summands' magnitude
- isomorphic to
java.lang.Double
when it comes to infinite or undefined values
The conversion between Duration and Double is done using Duration.toUnit (with unit NANOSECONDS) and Duration.fromNanos(Double)
Ordering
The default ordering is consistent with the ordering of Double numbers, which means that Undefined is considered greater than all other durations, including Duration.Inf.
- Source
- Duration.scala
- Alphabetic
- By Inheritance
- Duration
- Ordered
- Comparable
- Serializable
- AnyRef
- Any
- by orderingToOrdered
- by durationToPair
- by any2stringadd
- by StringFormat
- by Ensuring
- by ArrowAssoc
- Hide All
- Show All
- Public
- Protected
Abstract Value Members
- abstract def *(factor: Double): Duration
Return this duration multiplied by the scalar factor.
Return this duration multiplied by the scalar factor. When involving non-finite factors the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- abstract def +(other: Duration): Duration
Return the sum of that duration and this.
Return the sum of that duration and this. When involving non-finite summands the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- abstract def -(other: Duration): Duration
Return the difference of that duration and this.
Return the difference of that duration and this. When involving non-finite summands the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- abstract def /(divisor: Duration): Double
Return the quotient of this and that duration as floating-point number.
Return the quotient of this and that duration as floating-point number. The semantics are determined by Double as if calculating the quotient of the nanosecond lengths of both factors.
- abstract def /(divisor: Double): Duration
Return this duration divided by the scalar factor.
Return this duration divided by the scalar factor. When involving non-finite factors the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- abstract def compare(that: Duration): Int
Result of comparing
this
with operandthat
.Result of comparing
this
with operandthat
.Implement this method to determine how instances of A will be sorted.
Returns
x
where:x < 0
whenthis < that
x == 0
whenthis == that
x > 0
whenthis > that
- Definition Classes
- Ordered
- abstract def isFinite: Boolean
This method returns whether this duration is finite, which is not the same as
!isInfinite
for Double because this method also returnsfalse
for Duration.Undefined. - abstract def length: Long
Obtain the length of this Duration measured in the unit obtained by the
unit
method.Obtain the length of this Duration measured in the unit obtained by the
unit
method.- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toCoarsest: Duration
Return duration which is equal to this duration but with a coarsest Unit, or self in case it is already the coarsest Unit
Return duration which is equal to this duration but with a coarsest Unit, or self in case it is already the coarsest Unit
Examples:
Duration(60, MINUTES).toCoarsest // Duration(1, HOURS) Duration(1000, MILLISECONDS).toCoarsest // Duration(1, SECONDS) Duration(48, HOURS).toCoarsest // Duration(2, DAYS) Duration(5, SECONDS).toCoarsest // Duration(5, SECONDS)
- abstract def toDays: Long
Return the length of this duration measured in whole days, rounding towards zero.
Return the length of this duration measured in whole days, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toHours: Long
Return the length of this duration measured in whole hours, rounding towards zero.
Return the length of this duration measured in whole hours, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toMicros: Long
Return the length of this duration measured in whole microseconds, rounding towards zero.
Return the length of this duration measured in whole microseconds, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toMillis: Long
Return the length of this duration measured in whole milliseconds, rounding towards zero.
Return the length of this duration measured in whole milliseconds, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toMinutes: Long
Return the length of this duration measured in whole minutes, rounding towards zero.
Return the length of this duration measured in whole minutes, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toNanos: Long
Return the length of this duration measured in whole nanoseconds, rounding towards zero.
Return the length of this duration measured in whole nanoseconds, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toSeconds: Long
Return the length of this duration measured in whole seconds, rounding towards zero.
Return the length of this duration measured in whole seconds, rounding towards zero.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
- abstract def toUnit(unit: TimeUnit): Double
Return the number of nanoseconds as floating point number, scaled down to the given unit.
Return the number of nanoseconds as floating point number, scaled down to the given unit. The result may not precisely represent this duration due to the Double datatype's inherent limitations (mantissa size effectively 53 bits). Non-finite durations are represented as
- Duration.Undefined is mapped to Double.NaN
- Duration.Inf is mapped to Double.PositiveInfinity
- Duration.MinusInf is mapped to Double.NegativeInfinity
- abstract def unary_-: Duration
Negate this duration.
Negate this duration. The only two values which are mapped to themselves are Duration.Zero and Duration.Undefined.
- abstract def unit: TimeUnit
Obtain the time unit in which the length of this duration is measured.
Obtain the time unit in which the length of this duration is measured.
- Exceptions thrown
IllegalArgumentException
when invoked on a non-finite duration
Concrete Value Members
- final def !=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
true
if !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
- final def ##: Int
Equivalent to
x.hashCode
except for boxed numeric types andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. 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. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
- def ->[B](y: B): (Duration, B)
- Implicit
- This member is added by an implicit conversion from Duration toArrowAssoc[Duration] performed by method ArrowAssoc in scala.Predef.
- Definition Classes
- ArrowAssoc
- Annotations
- @inline()
- def <(that: Duration): Boolean
Returns true if
this
is less thanthat
Returns true if
this
is less thanthat
- Definition Classes
- Ordered
- def <=(that: Duration): Boolean
Returns true if
this
is less than or equal tothat
.Returns true if
this
is less than or equal tothat
.- Definition Classes
- Ordered
- final def ==(arg0: Any): Boolean
The expression
x == that
is equivalent toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (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
- AnyRef → Any
- def >(that: Duration): Boolean
Returns true if
this
is greater thanthat
.Returns true if
this
is greater thanthat
.- Definition Classes
- Ordered
- def >=(that: Duration): Boolean
Returns true if
this
is greater than or equal tothat
.Returns true if
this
is greater than or equal tothat
.- Definition Classes
- Ordered
- final def asInstanceOf[T0]: T0
Cast the receiver object to be of type
T0
.Cast the receiver object to be of type
T0
.Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression
1.asInstanceOf[String]
will throw aClassCastException
at runtime, while the expressionList(1).asInstanceOf[List[String]]
will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.- returns
the receiver object.
- Definition Classes
- Any
- Exceptions thrown
ClassCastException
if the receiver object is not an instance of the erasure of typeT0
.
- def clone(): AnyRef
Create a copy of the receiver object.
Create a copy of the receiver object.
The default implementation of the
clone
method is platform dependent.- returns
a copy of the receiver object.
- def compareTo(that: Duration): Int
Result of comparing
this
with operandthat
.Result of comparing
this
with operandthat
.- Definition Classes
- Ordered → Comparable
- def div(other: Duration): Double
Return the quotient of this and that duration as floating-point number.
Return the quotient of this and that duration as floating-point number. The semantics are determined by Double as if calculating the quotient of the nanosecond lengths of both factors.
- def div(divisor: Double): Duration
Return this duration divided by the scalar factor.
Return this duration divided by the scalar factor. When involving non-finite factors the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- def ensuring(cond: (Duration) => Boolean, msg: => Any): Duration
- Implicit
- This member is added by an implicit conversion from Duration toEnsuring[Duration] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: (Duration) => Boolean): Duration
- Implicit
- This member is added by an implicit conversion from Duration toEnsuring[Duration] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean, msg: => Any): Duration
- Implicit
- This member is added by an implicit conversion from Duration toEnsuring[Duration] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- def ensuring(cond: Boolean): Duration
- Implicit
- This member is added by an implicit conversion from Duration toEnsuring[Duration] performed by method Ensuring in scala.Predef.
- Definition Classes
- Ensuring
- final def eq(arg0: AnyRef): Boolean
Tests whether the argument (
that
) is a reference to the receiver object (this
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2
), they should be equal to each other (o1 == o2
) and they should hash to the same value (o1.hashCode == o2.hashCode
).- returns
true
if the argument is a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
- def equals(arg0: AnyRef): Boolean
The equality method for reference types.
- def finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the
finalize
method is invoked, as well as the interaction betweenfinalize
and non-local returns and exceptions, are all platform dependent.- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- Note
not specified by SLS as a member of AnyRef
- final def getClass(): Class[_ <: AnyRef]
Returns the runtime class representation of the object.
- def gt(other: Duration): Boolean
- def gteq(other: Duration): Boolean
- def hashCode(): Int
The hashCode method for reference types.
- 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 returnstrue
if the value of the receiver object is aBigDecimal
or a subtype ofBigDecimal
.T0
is a parameterized class type, e.g.List[Int]
: this method returnstrue
if the value of the receiver object is someList[X]
for anyX
. For example,List(1, 2, 3).isInstanceOf[List[String]]
will return true.T0
is some singleton typex.type
or literalx
: this method returnsthis.eq(x)
. For example,x.isInstanceOf[1]
is equivalent tox.eq(1)
T0
is an intersectionX with Y
orX & Y: this method is equivalent to
x.isInstanceOf[X] && x.isInstanceOf[Y]T0
is a unionX | Y
: this method is equivalent tox.isInstanceOf[X] || x.isInstanceOf[Y]
T0
is a type parameter or an abstract type member: this method is equivalent toisInstanceOf[U]
whereU
isT0
's upper bound,Any
ifT0
is unbounded. For example,x.isInstanceOf[A]
whereA
is an unbounded type parameter will return true for any value ofx
.
This is exactly equivalent to the type pattern
_: T0
- returns
true
if the receiver object is an instance of erasure of typeT0
;false
otherwise.
- Definition Classes
- Any
- Note
due to the unexpectedness of
List(1, 2, 3).isInstanceOf[List[String]]
returning true andx.isInstanceOf[A]
whereA
is a type parameter or abstract member returning true, these forms issue a warning.
- def lt(other: Duration): Boolean
- def lteq(other: Duration): Boolean
- def max(other: Duration): Duration
Return the larger of this and that duration as determined by the natural ordering.
- def min(other: Duration): Duration
Return the smaller of this and that duration as determined by the natural ordering.
- def minus(other: Duration): Duration
Return the difference of that duration and this.
Return the difference of that duration and this. When involving non-finite summands the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- def mul(factor: Double): Duration
Return this duration multiplied by the scalar factor.
Return this duration multiplied by the scalar factor. When involving non-finite factors the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- final def ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that)
.Equivalent to
!(this eq that)
.- returns
true
if the argument is not a reference to the receiver object;false
otherwise.
- Definition Classes
- AnyRef
- def neg(): Duration
Negate this duration.
Negate this duration. The only two values which are mapped to themselves are Duration.Zero and Duration.Undefined.
- final def notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
- final def notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Annotations
- @native()
- Note
not specified by SLS as a member of AnyRef
- def plus(other: Duration): Duration
Return the sum of that duration and this.
Return the sum of that duration and this. When involving non-finite summands the semantics match those of Double.
- Exceptions thrown
IllegalArgumentException
in case of a finite overflow: the range of a finite duration is+-(2^63-1)
ns, and no conversion to infinite durations takes place.
- def productArity: Int
The arity of this product.
- def productElement(n: Int): Any
Returns the n-th projection of this product if 0 <= n < productArity, otherwise throws an
IndexOutOfBoundsException
.Returns the n-th projection of this product if 0 <= n < productArity, otherwise throws an
IndexOutOfBoundsException
.- n
number of the projection to be returned
- returns
same as
._(n+1)
, for exampleproductElement(0)
is the same as._1
.
- Implicit
- This member is added by an implicit conversion from Duration to(Long, TimeUnit) performed by method durationToPair in scala.concurrent.duration.
- Definition Classes
- Product2 → Product
- Annotations
- @throws(clazz = classOf[IndexOutOfBoundsException])
- Exceptions thrown
IndexOutOfBoundsException
if then
is out of range(n < 0 || n >= 2).
- def productElementNames: Iterator[String]
An iterator over the names of all the elements of this product.
An iterator over the names of all the elements of this product.
- Implicit
- This member is added by an implicit conversion from Duration to(Long, TimeUnit) performed by method durationToPair in scala.concurrent.duration.
- Definition Classes
- Product
- def swap: (TimeUnit, Long)
Swaps the elements of this
Tuple
.Swaps the elements of this
Tuple
.- returns
a new Tuple where the first element is the second element of this Tuple and the second element is the first element of this Tuple.
- Implicit
- This member is added by an implicit conversion from Duration to(Long, TimeUnit) performed by method durationToPair in scala.concurrent.duration.
- Definition Classes
- Tuple2
- final def synchronized[T0](arg0: => T0): T0
Executes the code in
body
with an exclusive lock onthis
.Executes the code in
body
with an exclusive lock onthis
.- returns
the result of
body
- Definition Classes
- AnyRef
- def toString(): String
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
- returns
a String representation of the object.
- Definition Classes
- AnyRef → Any
- final def wait(): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait--.
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long, arg1: Int): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-int-
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- Note
not specified by SLS as a member of AnyRef
- final def wait(arg0: Long): Unit
See https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#wait-long-.
Shadowed Implicit Value Members
- def +(other: String): String
- Implicit
- This member is added by an implicit conversion from Duration toany2stringadd[Duration] performed by method any2stringadd in scala.Predef.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: any2stringadd[Duration]).+(other)
- Definition Classes
- any2stringadd
- def <(that: Duration): Boolean
Returns true if
this
is less thanthat
Returns true if
this
is less thanthat
- Implicit
- This member is added by an implicit conversion from Duration tomath.Ordered[Duration] performed by method orderingToOrdered in scala.math.Ordered.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: math.Ordered[Duration]).<(that)
- Definition Classes
- Ordered
- def <=(that: Duration): Boolean
Returns true if
this
is less than or equal tothat
.Returns true if
this
is less than or equal tothat
.- Implicit
- This member is added by an implicit conversion from Duration tomath.Ordered[Duration] performed by method orderingToOrdered in scala.math.Ordered.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: math.Ordered[Duration]).<=(that)
- Definition Classes
- Ordered
- def >(that: Duration): Boolean
Returns true if
this
is greater thanthat
.Returns true if
this
is greater thanthat
.- Implicit
- This member is added by an implicit conversion from Duration tomath.Ordered[Duration] performed by method orderingToOrdered in scala.math.Ordered.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: math.Ordered[Duration]).>(that)
- Definition Classes
- Ordered
- def >=(that: Duration): Boolean
Returns true if
this
is greater than or equal tothat
.Returns true if
this
is greater than or equal tothat
.- Implicit
- This member is added by an implicit conversion from Duration tomath.Ordered[Duration] performed by method orderingToOrdered in scala.math.Ordered.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: math.Ordered[Duration]).>=(that)
- Definition Classes
- Ordered
- def compare(that: Duration): Int
Result of comparing
this
with operandthat
.Result of comparing
this
with operandthat
.Implement this method to determine how instances of A will be sorted.
Returns
x
where:x < 0
whenthis < that
x == 0
whenthis == that
x > 0
whenthis > that
- Implicit
- This member is added by an implicit conversion from Duration tomath.Ordered[Duration] performed by method orderingToOrdered in scala.math.Ordered.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: math.Ordered[Duration]).compare(that)
- Definition Classes
- Ordered
- def compareTo(that: Duration): Int
Result of comparing
this
with operandthat
.Result of comparing
this
with operandthat
.- Implicit
- This member is added by an implicit conversion from Duration tomath.Ordered[Duration] performed by method orderingToOrdered in scala.math.Ordered.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: math.Ordered[Duration]).compareTo(that)
- Definition Classes
- Ordered → Comparable
- def toString(): String
Creates a String representation of this object.
Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.
- returns
a String representation of the object.
- Implicit
- This member is added by an implicit conversion from Duration to(Long, TimeUnit) performed by method durationToPair in scala.concurrent.duration.
- Shadowing
- This implicitly inherited member is shadowed by one or more members in this class.
To access this member you can use a type ascription:(duration: (Long, TimeUnit)).toString()
- Definition Classes
- Tuple2 → AnyRef → Any
Deprecated Value Members
- 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 forString.format
(@see java.lang.String.format).- Implicit
- This member is added by an implicit conversion from Duration toStringFormat[Duration] performed by method StringFormat in scala.Predef.
- Definition Classes
- StringFormat
- Annotations
- @deprecated @inline()
- Deprecated
(Since version 2.12.16) Use
formatString.format(value)
instead ofvalue.formatted(formatString)
, or use thef""
string interpolator. In Java 15 and later,formatted
resolves to the new method in String which has reversed parameters.
- def →[B](y: B): (Duration, B)
- Implicit
- This member is added by an implicit conversion from Duration toArrowAssoc[Duration] 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.
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int
,Float
,Array
orOption
which are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collection
and its sub-packages contain Scala's collections frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.sys
- Interaction with other processes and the operating systemscala.util.matching
- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect
- Scala's reflection API (scala-reflect.jar)scala.xml
- XML parsing, manipulation, and serialization (scala-xml.jar)scala.collection.parallel
- Parallel collections (scala-parallel-collections.jar)scala.util.parsing
- Parser combinators (scala-parser-combinators.jar)scala.swing
- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)Automatic imports
Identifiers in the scala package and the
scala.Predef
object are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
List
is an alias forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.