Interceptor Methods: __call() (Php Overloading)

Php provides  built-in interceptor methods.This also known as overloading but since that term means something quite different in Java and C++. PHP5  supports three built-in interceptor methods.Like __construct(), these are invoked for you when the right conditions are met.

Below  the tables describes this methods.

(PHP Objects, Patterns, and Practice  Book – Matt Zandstra – Apress.  Page 60.)

We  touch on __call() method for now. And i added an example how we can implement it.

/*
*  An Interceptor Example for __call() method
*  Ersin Güvenç.
*/

Class NameWriter
{
    /*
    *  @param - 1: name  - instance of Name Class
    */
    function writeName(Name $name)
    {
        print $name->getName();
    }

    function writeAge(Name $name)
    {
        print $name->getAge();
    }

}  //end of the class.

Class Name
{
    private $writer; //NameWriter instance

    function __construct(NameWriter $writer)
    {
        $this->writer = $writer;
    }

    /* our __call method */
    function __call($methodname, $args)
    {
        if(method_exists($this->writer, $methodname))
        {
            return $this->writer->$methodname($this);
        }
    }

    function getName() { return "John"; }
    function getAge() { return "27";}

} //end of the class.

//Our Super Object.
$name = new Name( new NameWriter() );

$name->writeName();
$name->writeAge();

//OUTPUT
//Jonn
//27

When the client makes this call to Name

$name = new Name( new NameWriter() );
$name->writeName();

the call method is invoked.We find a method called writeName() in our NameWriter object and invoke it.This saves us from manually invoking the delegated method like this:

function writeName {
     $this->writeName( $this );
}