Object Abstraction

PHP 5 introduces abstract classes and methods. An abstract method only declares the method's signature and does not provide an implementation. A class that contains abstract methods needs to be declared abstract.

Esempio 14-4.


<?php
abstract class AbstractClass {
   abstract public function test();
}

class ImplementedClass extends AbstractClass {
   public function test() {
       echo "ImplementedClass::test() called.\n";
   }
}

$o = new ImplementedClass;
$o->test();
?>

Abstract classes cannot be instantiated. Old code that has no user-defined classes or functions named 'abstract' should run without modifications.