Scala Standard Library2.12.21 < Back
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# Packages

-  package root

  This is the documentation for the Scala standard library.

  This is the documentation for the Scala standard library.

  #### Package structure

  The scala package contains core types like `Int`, `Float`, `Array` or `Option` 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 framework
    - `scala.collection.immutable` - Immutable, sequential data-structures such as `Vector`, `List`, `Range`, `HashMap` or `HashSet`
    - `scala.collection.mutable` - Mutable, sequential data-structures such as `ArrayBuffer`, `StringBuilder`, `HashMap` or `HashSet`
    - `scala.collection.concurrent` - Mutable, concurrent data-structures such as `TrieMap`
    - `scala.collection.parallel.immutable` - Immutable, parallel data-structures such as `ParVector`, `ParRange`, `ParHashMap` or `ParHashSet`
    - `scala.collection.parallel.mutable` - Mutable, parallel data-structures such as `ParArray`, `ParHashMap`, `ParTrieMap` or `ParHashSet`
  - `scala.concurrent` - Primitives for concurrent programming such as `Futures` and `Promises`
  - `scala.io` - Input and output operations
  - `scala.math` - Basic math functions and additional numeric types like `BigInt` and `BigDecimal`
  - `scala.sys` - Interaction with other processes and the operating system
  - `scala.util.matching` - Regular expressions

  Other 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.swing` - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)
  - `scala.util.parsing` - Parser combinators (scala-parser-combinators.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 for `scala.collection.immutable.List`.

  Other aliases refer to classes provided by the underlying platform. For example, on the JVM, `String` is an alias for `java.lang.String`.

  Definition Classes
    root
-  package scala

  Core Scala types.

  Core Scala types. They are always available without an explicit import.

  Definition Classes
    root
-  package util
  Definition Classes
    scala
-  package control
  Definition Classes
    util
-  package hashing
  Definition Classes
    util
-  package matching
  Definition Classes
    util
- DynamicVariable
- Either
- Failure
- Left
- MurmurHash
- Properties
- Random
- Right
- Sorting
- Success
- Try

o

scala.util

# Properties 

###

#### object Properties extends PropertiesTrait

Loads `library.properties` from the jar.

Source
  Properties.scala

Linear Supertypes
PropertiesTrait, AnyRef, Any
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Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. Properties
2. PropertiesTrait
3. AnyRef
4. Any

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Visibility

1. Public
2. All

### 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
     AnyRef → 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
     AnyRef → Any
3.  final def ==(arg0: Any): Boolean

   The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

   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
     AnyRef → Any
4.  val ScalaCompilerVersion: Name

   Scala manifest attributes.

5.  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 a `ClassCastException` at runtime, while the expression `List(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 type `T0`.

6.  def clearProp(name: String): String
   Definition Classes
     PropertiesTrait
7.  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.

   Attributes
     protected[lang]
   Definition Classes
     AnyRef
   Annotations
     @throws( ... ) @native()
   Note

     not specified by SLS as a member of AnyRef

8.  val copyrightString: String
   Definition Classes
     PropertiesTrait
9.  val developmentVersion: Option[String]

   The development Scala version, if this is not a final release.

   The development Scala version, if this is not a final release. The precise contents are not guaranteed, but it aims to provide a unique repository identifier (currently the svn revision) in the fourth dotted segment if the running version was built from source.

   returns

     Some(version) if this is a non-final version, None if this is a final release or the version cannot be read.

   Definition Classes
     PropertiesTrait
10.  def encodingString: String

    This is the default text encoding, overridden (unreliably) with `JAVA_OPTS="-Dfile.encoding=Foo"`

    This is the default text encoding, overridden (unreliably) with `JAVA_OPTS="-Dfile.encoding=Foo"`

    Definition Classes
      PropertiesTrait
11.  def envOrElse(name: String, alt: String): String
    Definition Classes
      PropertiesTrait
12.  def envOrNone(name: String): Option[String]
    Definition Classes
      PropertiesTrait
13.  def envOrSome(name: String, alt: Option[String]): Option[String]
    Definition Classes
      PropertiesTrait
14.  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 of `AnyRef`, and has three additional properties:

    - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
    - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
    - `null.eq(null)` returns `true`.

    When overriding the `equals` or `hashCode` 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
15.  def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to `eq`.

    See also `equals` in scala.Any.

    returns

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

    Definition Classes
      AnyRef → Any
16.  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 between `finalize` 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

17.  final def getClass(): Class[_]

    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
      AnyRef → Any
    Annotations
      @native()
18.  def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

      the hash code value for this object.

    Definition Classes
      AnyRef → Any
    Annotations
      @native()
19.  final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. 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 specified type.

    returns

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

    Definition Classes
      Any
20.  def isJavaAtLeast(version: String): Boolean

    Compares the given specification version to the specification version of the platform.

    Compares the given specification version to the specification version of the platform.

    version

      a specification version number (legacy forms acceptable)

    returns

      `true` if the specification version of the current runtime is equal to or higher than the version denoted by the given string.

    Definition Classes
      PropertiesTrait
    Example:

    1.     // In this example, the runtime's Java specification is assumed to be at version 8.
           isJavaAtLeast("1.8")            // true
           isJavaAtLeast("8")              // true
           isJavaAtLeast("9")              // false
           isJavaAtLeast("9.1")            // false
           isJavaAtLeast("1.9")            // throws

    Exceptions thrown

      `NumberFormatException` if the given string is not a version string

21.  def isLinux: Boolean

    Returns `true` iff the underlying operating system is a Linux distribution.

    Returns `true` iff the underlying operating system is a Linux distribution.

    Definition Classes
      PropertiesTrait
22.  def isMac: Boolean

    Returns `true` iff the underlying operating system is a version of Apple Mac OSX.

    Returns `true` iff the underlying operating system is a version of Apple Mac OSX.

    Definition Classes
      PropertiesTrait
23.  def isWin: Boolean

    Returns `true` iff the underlying operating system is a version of Microsoft Windows.

    Returns `true` iff the underlying operating system is a version of Microsoft Windows.

    Definition Classes
      PropertiesTrait
24.  def javaClassPath: String
    Definition Classes
      PropertiesTrait
25.  def javaHome: String
    Definition Classes
      PropertiesTrait
26.  def javaSpecName: String
    Definition Classes
      PropertiesTrait
27.  def javaSpecVendor: String
    Definition Classes
      PropertiesTrait
28.  def javaSpecVersion: String
    Definition Classes
      PropertiesTrait
29.  def javaVendor: String
    Definition Classes
      PropertiesTrait
30.  def javaVersion: String
    Definition Classes
      PropertiesTrait
31.  def javaVmInfo: String
    Definition Classes
      PropertiesTrait
32.  def javaVmName: String
    Definition Classes
      PropertiesTrait
33.  def javaVmVendor: String
    Definition Classes
      PropertiesTrait
34.  def javaVmVersion: String
    Definition Classes
      PropertiesTrait
35.  def jdkHome: String
    Definition Classes
      PropertiesTrait
36.  def lineSeparator: String

    The default end of line character.

    The default end of line character.

    Definition Classes
      PropertiesTrait
37.  def main(args: Array[String]): Unit
    Definition Classes
      PropertiesTrait
38.  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
39.  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

40.  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

41.  def osName: String
    Definition Classes
      PropertiesTrait
42.  def pickJarBasedOn: Class[Option[_]]
    Attributes
      protected
    Definition Classes
      Properties → PropertiesTrait
43.  def propCategory: String
    Attributes
      protected
    Definition Classes
      Properties → PropertiesTrait
44.  val propFilename: String

    The name of the properties file

    The name of the properties file

    Attributes
      protected
    Definition Classes
      PropertiesTrait
45.  def propIsSet(name: String): Boolean
    Definition Classes
      PropertiesTrait
46.  def propIsSetTo(name: String, value: String): Boolean
    Definition Classes
      PropertiesTrait
47.  def propOrElse(name: String, alt: String): String
    Definition Classes
      PropertiesTrait
48.  def propOrEmpty(name: String): String
    Definition Classes
      PropertiesTrait
49.  def propOrFalse(name: String): Boolean
    Definition Classes
      PropertiesTrait
50.  def propOrNone(name: String): Option[String]
    Definition Classes
      PropertiesTrait
51.  def propOrNull(name: String): String
    Definition Classes
      PropertiesTrait
52.  val releaseVersion: Option[String]

    The numeric portion of the runtime Scala version, if this is a final release.

    The numeric portion of the runtime Scala version, if this is a final release. If for instance the versionString says "version 2.9.0.final", this would return Some("2.9.0").

    returns

      Some(version) if this is a final release build, None if it is an RC, Beta, etc. or was built from source, or if the version cannot be read.

    Definition Classes
      PropertiesTrait
53.  def scalaCmd: String
    Definition Classes
      PropertiesTrait
54.  def scalaHome: String
    Definition Classes
      PropertiesTrait
55.  def scalaPropOrElse(name: String, alt: String): String
    Definition Classes
      PropertiesTrait
56.  def scalaPropOrEmpty(name: String): String
    Definition Classes
      PropertiesTrait
57.  def scalaPropOrNone(name: String): Option[String]
    Definition Classes
      PropertiesTrait
58.  lazy val scalaProps: java.util.Properties

    The loaded properties

    The loaded properties

    Attributes
      protected
    Definition Classes
      PropertiesTrait
59.  def scalacCmd: String
    Definition Classes
      PropertiesTrait
60.  def setProp(name: String, value: String): String
    Definition Classes
      PropertiesTrait
61.  def sourceEncoding: String

    This is the encoding to use reading in source files, overridden with -encoding.

    This is the encoding to use reading in source files, overridden with -encoding. Note that it uses "prop" i.e. looks in the scala jar, not the system properties.

    Definition Classes
      PropertiesTrait
62.  def sourceReader: String
    Definition Classes
      PropertiesTrait
63.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
64.  def tmpDir: String
    Definition Classes
      PropertiesTrait
65.  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
66.  def userDir: String
    Definition Classes
      PropertiesTrait
67.  def userHome: String
    Definition Classes
      PropertiesTrait
68.  def userName: String
    Definition Classes
      PropertiesTrait
69.  def versionMsg: String
    Definition Classes
      PropertiesTrait
70.  def versionNumberString: String

    Either the development or release version if known, otherwise the empty string.

    Either the development or release version if known, otherwise the empty string.

    Definition Classes
      PropertiesTrait
71.  val versionString: String

    The version number of the jar this was loaded from plus "version " prefix, or "version (unknown)" if it cannot be determined.

    The version number of the jar this was loaded from plus "version " prefix, or "version (unknown)" if it cannot be determined.

    Definition Classes
      PropertiesTrait
72.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
73.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
74.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... ) @native()

### Inherited from PropertiesTrait

### Inherited from AnyRef

### Inherited from Any

### Ungrouped