scala

Application

trait Application extends AnyRef

The Application trait can be used to quickly turn objects into executable programs, but is not recommended. Here is an example: 

 object Main extends Application {
   Console.println("Hello World!")
 }

Here, object Main inherits the main method of Application. The body of the Main object defines the main program. This technique does not work if the main program depends on command-line arguments (which are not accessible with the technique presented here).

It is possible to time the execution of objects that inherit from class Application by setting the global scala.time property. Here is an example for benchmarking object Main: 

 java -Dscala.time Main

In practice the Application trait has a number of serious pitfalls:

Instead, it is recommended to define a main method explicitly: 

 object Main {
   def main(args: Array[String]) {
     //..
   }
 }

Inherits

  1. AnyRef
  2. Any

Value Members

  1. def equals(arg0: Any): Boolean

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence.

    The default implementations of this method is an equivalence relation:

    • It is reflexive: for any instance x of type Any, x.equals(x) should return true.
    • It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true.
    • It is transitive: for any instances x, y, and z of type AnyRef if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

    If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is often necessary to override hashCode to ensure that objects that are "equal" (o1.equals(o2) returns true) hash to the same Int (o1.hashCode.equals(o2.hashCode)).

    arg0

    the object to compare against this object for equality.

    returns

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

    definition classes: AnyRef ⇐ Any

  2. val executionStart: Long

    The time when execution of this program started

    The time when execution of this program started.

  3. def hashCode(): Int

    Returns a hash code value for the object

    Returns a hash code value for the object.

    The default hashing algorithm is platform dependent.

    Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

    definition classes: AnyRef ⇐ Any

  4. def main(args: Array[String]): Unit

    The default main method

    The default main method.

    args

    the arguments passed to the main method

  5. def toString(): String

    Returns a string representation of the object

    Returns a string representation of the object.

    The default representation is platform dependent.

    definition classes: AnyRef ⇐ Any