Packages

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 ", "))
}

No explicit main method is needed. Instead, the whole class body becomes the “main method”.

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.

Future versions of this trait will no longer extend DelayedInit.

Source
App.scala
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Inherited
  1. App
  2. DelayedInit
  3. AnyRef
  4. Any
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  1. by any2stringadd
  2. by StringFormat
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Visibility
  1. Public
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Value Members

  1. final val executionStart: Long

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

  2. final 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

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