Best way to do multiple constructors in PHP

Question

You can't put two __construct functions with unique argument signatures in a PHP class. I'd like to do this:

class Student  {    protected $id;    protected $name;    // etc.     public function __construct($id){        $this->id = $id;       // other members are still uninitialized    }     public function __construct($row_from_database){        $this->id = $row_from_database->id;        $this->name = $row_from_database->name;        // etc.    } } 

What is the best way to do this in PHP?

Answer 1

I'd probably do something like this:

<?php  class Student {     public function __construct() {         // allocate your stuff     }      public static function withID( $id ) {         $instance = new self();         $instance->loadByID( $id );         return $instance;     }      public static function withRow( array $row ) {         $instance = new self();         $instance->fill( $row );         return $instance;     }      protected function loadByID( $id ) {         // do query         $row = my_awesome_db_access_stuff( $id );         $this->fill( $row );     }      protected function fill( array $row ) {         // fill all properties from array     } }  ?> 

Then if i want a Student where i know the ID:

$student = Student::withID( $id ); 

Or if i have an array of the db row:

$student = Student::withRow( $row ); 

Technically you're not building multiple constructors, just static helper methods, but you get to avoid a lot of spaghetti code in the constructor this way.