Question

I have an abstract class and child’s:

abstract class Cubique_Helper_Abstract {
    abstract public function execute();
}

class Cubique_Helper_Doctype extends Cubique_Helper_Abstract{
    public function execute($type) {}
}

As you can see, method execute() is common. But number of arguments can be different in all classes. How can I keep this extending with different arguments of method?

It’s my current error:

Declaration of Cubique_Helper_Doctype::execute() must be compatible
with that of Cubique_Helper_Abstract::execute()

Thank you i advance.

Answer 1

• You could remove execute() from the abstract, but you probably do not want to do that.

• You could also give it an data object as argument, like this:

  class MyOptions {
    public function getType(){}
    public function getStuff(){}
  }
  
  abstract class Cubique_Helper_Abstract {
      abstract public function execute(MyOptions $options);
  }
  
  class Cubique_Helper_Doctype extends Cubique_Helper_Abstract{
    public function execute(MyOptions $options) {
      $type = $options->getType();
    }
  }
  

• Or, you could make it depend on values in constructor and leave out the argument:

  abstract class Cubique_Helper_Abstract {
      abstract public function execute();
  }
  
  class Cubique_Helper_Doctype extends Cubique_Helper_Abstract{
    public function __construct($type) {
      // since __construct() is not in abstract, it can be different
      // from every child class, which let's you handle dependencies
      $this->type = $type;
    }
    public function execute() {
      // you have $this->type here
    }
  }
  

The last alternative is my favorite. This way, you really make sure you have the dependencies and when it’s time to execute() you don’t have to give it any arguments.

---

I would not use func_get_args() since you lose track of dependencies. Example:

class Cubique_Helper_Doctype extends Cubique_Helper_Abstract {
  public function execute() {
    $args = func_get_args();
    $type = $args[0];
    $title = $args[1];
    $content = $args[2];
    // do something, for example
    echo $type; // will always echo "" if you miss arguments, but you really want a fatal error
  }
}

$d = new Cubique_Helper_Doctype();
$d->execute();
// this is a valid call in php, but it ruins your application.
// you **want** it to fail so that you know what's wrong (missing dependencies)