php--Final keyword

PHP 5 adds a new final keyword. If a method in the parent class is declared final, the child class cannot override the method. If a class is declared final, it cannot be inherited.

Example #1 Final method example

class BaseClass
{
    public function test(){
        echo "BaseClass::test() called<br>";
    }
    final public function moreTesting(){
        echo "BaseClass::moreTesting() called<br>";
    }
}
class ChildClass extends BaseClass
{
    public function moreTesting(){
        echo "BaseClass::moreTeing called<br>";
    }
}

Example #2 Final class example

final class BaseClass{
    public function test(){
        echo "BaseClass::test() called\n";
    }
    //这里无论你是否将方法声明为final，都没有关系
    final public function moreTesting(){
        echo "BaseClass::moreTesting() called\n";
    }
}
class ChildClass extends BaseClass{}
//产生Fatal Error:Class ChildClass may not inherit from final class (BaseClass)

Note: Properties cannot be defined as final, only classes and methods can be defined as final.