PHP获取子类方法

Question

Is it possible in PHP to get the methods of an extended child class in a method declared in the parent class?

Here is a simple (maybe stupid) example:

<?php

class Vehicle{
    protected function moveForward(){
        // go ahead...
    }// moveForward

    public function getWhatCanIDo(){
        $actions = get_class_methods($this);
        return 'I can '.implode(', ', $actions).'<br/>';
    }// getWhatCanIDo
}


class Car extends Vehicle{
    protected function honk(){
        // honk...
    }// honk

    protected function turnHeadlightsOn(){
        // turn headlights on...
    }// turnHeadlightsOn

    protected function stopEngine(){
        // stop the engine
    }// stopEngine
}


class Submarine extends Vehicle{
    protected function submerge(){
        // sink...
    }// submerge

    protected function ping(){
        // ping...
    }// ping

    protected function fireTorpedos(){
        // DESTROY!!!
    }// fireTorpedos

    protected function stopEngine(){
        // stop the engine
    }// stopEngine
}


$volvo = new Car();
$uboat = new Submarine();

echo $volvo->getWhatCanIDo();
echo $uboat->getWhatCanIDo();

?>

The output what I expect is:

I can moveForward, getWhatCanIDo, honk, turnHeadlightsOn, stopEngine
I can moveForward, getWhatCanIDo, submerge, ping, fireTorpedos, stopEngine

But instead It returns the the methos of the Vehicle class only, without the methods implemented in the extended class:

I can moveForward, getWhatCanIDo
I can moveForward, getWhatCanIDo

How could I get the extanded class methods?

Additional Infos: I have to solve this in PHP 5.2.14 The extended classes will have different numbers of methods with different method names so making Vehicle an abstract class wont help, because eg: I dont want Submarine to have honk method. I know I could make the getWhatCanIDo() an abstract method, but I'd like to implement this method "centrally" in the parent class, I dont want to oblige developers to write getWhatCanIDo() method for every extended class (In the future others may join or continue this project, and Its more failsafe to not let them implement this method again and again especially when the method does exactly the same thing.)

Answer 1

You should declare class Vehicle abstract, because it does not really exist and the real vehicles implement it.

Then put whatCanIDo in Car and in Submarine , because you don't ask the vehicle what it can do, you ask the car.

class Car extends Vehicle{
    public function getWhatCanIDo(){
        $actions = get_class_methods($this);
        return 'I can '.implode(', ', $actions).'<br/>';
    }// getWhatCanIDo
}

Update:

A yet different approach is to use the standard PHP library ReflectionClass :

$class   = new ReflectionClass('Vehicle');
$methods = $class->getMethods();

Answer 2

You need to overload the getWhatCanIDo() function in the Car & Submarine classes. You get the output because the function is executed in the Vehicle class.

Overloading the method causes it to be executed in either the Car or Submarine class.

Answer 3

You could also try get_class_methods(); More at http://www.php.net/manual/en/function.get-class-methods.php

Answer 4

This code is not tested, please, let me know if it works.

class MyBaseClass {
    //...
    public function getMethods($className) {
        return get_class_methods($className);
    }

    public static function getMethods($myObject) {
        return $myObject->getMethods(get_class($myObject));
    }
    //...
}

class MyInheritedClass {
    //...
}

$myBaseObject = new MyBaseClass(/*...*/);
$myInheritedObject = new MyInheritedClass(/*...*/);
echo var_dump(MyBaseClass::getMethods($myBaseObject));
echo var_dump(MyBaseClass::getMethods($myInheritedObject));

Answer 5

Inheritance is not proper tool here. You should use composition. Example:

1. Have separate objects Runner, Swimmer, WorkWithEngine, Submerge. All off them implements interface with getWhatCanIDo() method.

2. Create your new Vehiclas by composing them from Types from point one. This object implements interface with getWhatCanIDo() method as well.

$submarine = new Submarine(); $submarine->addAblility(new Swimmer()); $submarine->addAblility(new WorkWithEngine()); $submarine->addAblility(new Submerge()); $submarine->whatCanIDo();

In any case do not use magic like get_class_methods those are constructs for frameworks creators it is not stuff for coding business logic.