Access Modifiers in Scala
Access Modifiers in scala are used to define the access field of members of packages, classes or objects in scala.For using an access modifier, you must include its keyword in the definition of members of package, class or object.These modifiers will restrict accesses to the members to specific regions of code.
There are Three types of access modifiers available in Scala:
- Private
- Protected
- Public
Table:
Modifier | Class | Companion | Subclass | Package | World |
---|---|---|---|---|---|
No Modifier/Public | Yes | Yes | Yes | Yes | Yes |
Protected | Yes | Yes | Yes | No * | No |
Private | Yes | Yes | No | No * | No |
What is companion in above table? It is a singleton object named same as the class.
1. Private: When a member is declared as private, we can only use it inside defining class or through one of its objects.
Example:
// Scala program of private access modifier class abc { private var a : Int = 123 def display() { a = 8 println(a) } } object access extends App { // class abc is accessible // because this is in the same enclosing scope var e = new abc() e.display() } |
Output:
8
Here we declared a variable ‘a’ private and now it can be accessed only inside it’s defining class or through classes object.
2. Protected: They can be only accessible from sub classes of the base class in which the member has been defined.
Example:
// Scala program of protected access modifier class gfg { // declaration of protected member protected var a : Int = 123 def display() { a = 8 println(a) } } // class new1 extends by class gfg class new 1 extends gfg { def display 1 () { a = 9 println(a) } } object access extends App { // class abc is accessible because this // is in the same enclosing scope var e = new gfg() e.display() var e 1 = new new 1 () e 1 .display 1 () } |
Output:
8 9
When we extended abc in class new1, protected variable a is now available to be modified cause new1 is a subclass of class abc.
3. Public: There is no public keyword in Scala. The default access level (when no modifier is specified) corresponds to Java’s public access level.We can access these anywhere.
// Scala program of protected access modifier class gfg { var a : Int = 123 } object access extends App { var e = new gfg() e.a = 444 println(e.a) } |
Output:
444