scala

App

trait App extends DelayedInit

The App trait can be used to quickly turn objects into executable programs. Here is an example:

object Main extends App {
Console.println("Hello World: " + (args mkString ", "))
}

Here, object Main inherits the main method of App.

args returns the current command line arguments as an array.

Caveats

It should be noted that this trait is implemented using the DelayedInit functionality, which means that fields of the object will not have been initialized before the main method has been executed.

It should also be noted that the main method should not be overridden: the whole class body becomes the “main method”.

Future versions of this trait will no longer extend DelayedInit.

Source
App.scala
Version

2.1, 15/02/2011

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Inherited
  1. App
  2. DelayedInit
  3. AnyRef
  4. Any
Implicitly
  1. by any2stringadd
  2. by StringFormat
  3. by Ensuring
  4. by ArrowAssoc
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Value Members

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

    Definition Classes
    AnyRef → Any
  2. final def ##(): Int

    Definition Classes
    AnyRef → Any
  3. def +(other: String): String

    Implicit information
    This member is added by an implicit conversion from App to any2stringadd[App] performed by method any2stringadd in scala.Predef.
    Definition Classes
    any2stringadd
  4. def ->[B](y: B): (App, B)

    Implicit information
    This member is added by an implicit conversion from App to ArrowAssoc[App] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc
    Annotations
    @inline()
  5. final def ==(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any
  6. def args: Array[String]

    The command line arguments passed to the application's main method.

    The command line arguments passed to the application's main method.

    Attributes
    protected
    Annotations
    @deprecatedOverriding( "args should not be overridden" , "2.11.0" )
  7. final def asInstanceOf[T0]: T0

    Definition Classes
    Any
  8. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  9. def ensuring(cond: (App) ⇒ Boolean, msg: ⇒ Any): App

    Implicit information
    This member is added by an implicit conversion from App to Ensuring[App] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  10. def ensuring(cond: (App) ⇒ Boolean): App

    Implicit information
    This member is added by an implicit conversion from App to Ensuring[App] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  11. def ensuring(cond: Boolean, msg: ⇒ Any): App

    Implicit information
    This member is added by an implicit conversion from App to Ensuring[App] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  12. def ensuring(cond: Boolean): App

    Implicit information
    This member is added by an implicit conversion from App to Ensuring[App] performed by method Ensuring in scala.Predef.
    Definition Classes
    Ensuring
  13. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  14. def equals(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any
  15. val executionStart: Long

    The time when the execution of this program started, in milliseconds since 1 January 1970 UTC.

  16. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  17. 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 information
    This member is added by an implicit conversion from App to StringFormat[App] performed by method StringFormat in scala.Predef.
    Definition Classes
    StringFormat
    Annotations
    @inline()
  18. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any
  19. def hashCode(): Int

    Definition Classes
    AnyRef → Any
  20. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any
  21. def main(args: Array[String]): Unit

    The main method.

    The main method. This stores all arguments so that they can be retrieved with args and then executes all initialization code segments in the order in which they were passed to delayedInit.

    args

    the arguments passed to the main method

    Annotations
    @deprecatedOverriding( "main should not be overridden" , "2.11.0" )
  22. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef
  23. final def notify(): Unit

    Definition Classes
    AnyRef
  24. final def notifyAll(): Unit

    Definition Classes
    AnyRef
  25. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef
  26. def toString(): String

    Definition Classes
    AnyRef → Any
  27. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  28. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  29. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  30. def [B](y: B): (App, B)

    Implicit information
    This member is added by an implicit conversion from App to ArrowAssoc[App] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
    ArrowAssoc

Deprecated Value Members

  1. def delayedInit(body: ⇒ Unit): Unit

    The init hook.

    The init hook. This saves all initialization code for execution within main. This method is normally never called directly from user code. Instead it is called as compiler-generated code for those classes and objects (but not traits) that inherit from the DelayedInit trait and that do not themselves define a delayedInit method.

    body

    the initialization code to be stored for later execution

    Definition Classes
    AppDelayedInit
    Annotations
    @deprecated
    Deprecated

    (Since version 2.11.0) The delayedInit mechanism will disappear.

Inherited from DelayedInit

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from App to any2stringadd[App]

Inherited by implicit conversion StringFormat from App to StringFormat[App]

Inherited by implicit conversion Ensuring from App to Ensuring[App]

Inherited by implicit conversion ArrowAssoc from App to ArrowAssoc[App]

Ungrouped