CODEWITHSUNDEEP
scalaprogram-entry-point
Jonathan Myers
Jonathan Myers

Reputation: 930

Calling main methods in other objects in Scala

Is it possible to call a main method in one object from a main method in another? I have the following classes and was wondering how to call two separate main methods within one program run:

object MongoUpload {
  def main(args: Array[String]): Unit = {
    .. upload to Mongo ..
    // Want to upload to Oracle here
  }
}

object OracleUpload {
  def main(args: Array[String]): Unit = {
    .. upload to Oracle
  }
}

Does anything make main unique among methods? Can I just call one from another?

Upvotes: 3

Views: 2296

Answers (1)

Jonathan Myers
Jonathan Myers

Reputation: 930

You sure can. Just like any other method, main can be called between objects.


object foo {
  def main(args: Array[String]): Unit = {
    println("qux")
  }
}

object bar {
  def main(args: Array[String]): Unit = {
    println("baz")
    foo.main(null)
  }
}

Running main in bar gives the following output:

baz
qux

The same can also be replicated to main methods with arguments, as in the following example:

object foo {
  def main(args: Array[String]): Unit = {
    println(args(0) + " " + args(1))
  }
}

object bar {
  def main(args: Array[String]): Unit = {
    ... some processing ...
    foo.main(Array["Hello", "World"])
  }
}

Running main in bar gives the following output:

Hello World

Whether or not it leads to clear and readable code is another question :)

Upvotes: 7

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