Swift readonly external, readwrite internal property
As per @Antonio, we can use a single property to access as the readOnly
property value publicly and readWrite
privately. Below is my illustration:
class MyClass {
private(set) public var publicReadOnly: Int = 10
//as below, we can modify the value within same class which is private access
func increment() {
publicReadOnly += 1
}
func decrement() {
publicReadOnly -= 1
}
}
let object = MyClass()
print("Initial valule: \(object.publicReadOnly)")
//For below line we get the compile error saying : "Left side of mutating operator isn't mutable: 'publicReadOnly' setter is inaccessible"
//object.publicReadOnly += 1
object.increment()
print("After increment method call: \(object.publicReadOnly)")
object.decrement()
print("After decrement method call: \(object.publicReadOnly)")
And here is the output:
Initial valule: 10
After increment method call: 11
After decrement method call: 10
Given a class property, you can specify a different access level by prefixing the property declaration with the access modifier followed by get
or set
between parenthesis. For example, a class property with a public getter and a private setter will be declared as:
private(set) public var readonlyProperty: Int
Suggested reading: Getters and Setters
Martin's considerations about accessibility level are still valid - i.e. there's no protected
modifier, internal
restricts access to the module only, private
to the current file only, and public
with no restrictions.
Swift 3 notes
2 new access modifiers, fileprivate
and open
have been added to the language, while private
and public
have been slightly modified:
open
applies to class and class members only: it's used to allow a class to be subclassed or a member to be overridden outside of the module where they are defined.public
instead makes the class or the member publicly accessible, but not inheritable or overridableprivate
now makes a member visible and accessible from the enclosing declaration only, whereasfileprivate
to the entire file where it is contained
More details here.