final to prevent from overriding the constant by the child class. Of course current class constant functionality remains the same.The final modifier can be added to class constants. Doing so prevents overriding of a constant:
class Foo
{
final public const X = "foo";
}
class Bar extends Foo
{
public const X = "bar";
}
// Fatal error: Bar::X cannot override final constant Foo::XBesides, interface constants would become overridable by default, and the final modifier could be used to retain the original behavior.
interface I
{
public const X = "i";
final public const Y = "i";
}
class C implements I
{
public const X = "c"; // Overriding I::X is possible
public const Y = "c"; // Overriding I::Y is not possible
}
// Fatal error: C::Y cannot override final constant I::Y
