Access Modifiers in Scala

Access modifiers in Scala are keywords that control the visibility of classes, objects, and members (variables and methods) within your code. Understanding these modifiers is essential for encapsulating data and controlling access to different parts of your program.

Key Concepts

• Encapsulation: This is a core principle of object-oriented programming, which restricts access to certain components and protects the integrity of the data.
• Access Modifiers: Scala provides several access modifiers to control visibility.

Types of Access Modifiers

1. Public
   • Description: Members marked as public are accessible from anywhere in the code.
   • Default Modifier: If no modifier is specified, members are public.
2. Private
   • Description: Members marked as private are accessible only within the class or object where they are defined.
3. Protected
   • Description: Members marked as protected are accessible within the class and by subclasses (children classes).
4. Package-private (Default)
   • Description: Members without any modifier are accessible only within the same package.

Example:

class Vehicle {
  var model: String = "Sedan"  // Accessible within the same package
}

Example:

class Animal {
  protected var species: String = "Mammal"  // Accessible in subclasses
}
class Dog extends Animal {
  def printSpecies(): Unit = {
    println(species)  // Accessible here
  }
}

Example:

class Person {
  private var age: Int = 30  // Accessible only within this class
}

Example:

class Person {
  var name: String = "John"  // Public by default
}

Conclusion

Understanding access modifiers is crucial for maintaining the integrity and security of your data in Scala. By using public, private, protected, and default package-private access properly, you can create robust and organized code structures that clearly define which parts of your program can interact with each other.