抽象类

PHP 5 中引入了抽象类及方法的概念。 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.

例子 19-6. 抽象类代码实例


<?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();
?>

抽象类不能被实例化。Old code that has no user-defined classes or functions named 'abstract' should run without modifications.