Call a method on a Super Class in Scala
This concept is used when we want to call super class method. So whenever a base and subclass have same named methods then to resolve ambiguity we use super keyword to call base class method. The keyword “super” came into this with the concept of Inheritance.
Below is the example of call a method on a superclass.
Example #1:
// Scala program to call a method // on a superclass in Scala /* Base class ComputerScience */ class ComputerScience { def read { println( "I'm reading" ) } def write { println( "I'm writing" ) } } /* Subclass Scala */ class Scala extends ComputerScience { // Note that readThanWrite() is only in Scala class def readThanWrite() { // Will invoke or call parent class read() method super .read // Will invoke or call parent class write() method super .write } } // Creating object object Beginner { // Main method def main(args : Array[String]) { var ob = new Scala(); // Calling readThanWrite() of Scala ob.readThanWrite(); } } |
Output:
I'm reading I'm writing
In above example, we are calling multiple method of super class by using super keyword.
Example #2:
// Scala program to call a method // on a superclass in Scala /* Super class Person */ class Person { def message() { println( "This is person class" ); } } /* Subclass Student */ class Student extends Person { override def message() { println( "This is student class" ) } // Note that display() is only in Student class def display() { // will invoke or call current class message() method message () // will invoke or call parent class message() method super .message } } /* Creating object */ object Beginner { // Main method def main(args : Array[String]) { var s = new Student(); // Calling display() of Student s.display(); } } |
Output:
This is student class This is person class
In the above example, we have seen that if we only call method message()
then, the current class message()
is invoked but with the use of super keyword, message()
of super class could also be invoked.