define multi function with same name and different argument type in PHP

Question

Possible Duplicate:
PHP OOP: Unique method per argument type?
PHP 5.3 method overloading (like in Java)

I have some different class like users and groups. I want to create a general class to add attribute of the class. My class has some function like add, delete, edit and etc. for example:

<?php
class Persistence{
    function add(Users $userObj){
        ....
    }
    function add(Groups $groupObj){
        ....
    }
}
?>

How can I do this?

PatrikAkerstrand · Accepted Answer · 2012-10-22T07:09:36.003

5

While type hinting is allowed in PHP, method overloading based on argument types is not. So you need to create different methods for each of your cases and use these instead. What you can do, however, is drop the type hinting from the add-method, and use if-else statements or a switch on the argument instead:

public function add ($collection) }
   if($collection instanceof Users) {
     return $this->addUsers($collection);
   }
   if($collection instanceof Groups) {
     return $this->addGroups($collection);
   }
   ...
   throw new InvalidArgumentException("Unknown collection type");
}

public function addUsers(Users $users) {
}

public function addGroups(Groups $groups) {
}

edited Oct 22 '12 at 07:09

answered Oct 22 '12 at 05:24

PatrikAkerstrand

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This way is best way, I think – Mahdi Mojiry Oct 22 '12 at 05:33
1

I would improve this by making the "addUsers" and "addGroups" private and only present "add" for use. – Clutch Oct 25 '13 at 20:45

score 2 · Answer 2 · answered Oct 22 '12 at 05:17

2

Method overloading like this is not possible; you have to weaken the predicate in the declaration:

function add($obj)
{
    if ($obj instanceof Users) {
    } elseif ($obj instanceof Groups) {
    } else {
        throw new Exception("Invalid type for object");
    }
}

answered Oct 22 '12 at 05:17

Ja͢ck

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Thanks a lot. This is fastest answer! – Mahdi Mojiry Oct 22 '12 at 05:36

score 2 · Answer 3 · answered Oct 22 '12 at 05:24

An alternative solution is to create an interface for your Persistence class:

interface PersistenceInterface { /* ... */ }

class Users implements PersistenceInterface { /* ... */ }
class Groups implements PersistenceInterface { /* ... */ }

class Persistence
{
    public function add(PersistenceInterface $userObj)
    {
        // ...
    }
}

This way, only objects marked with the interface are allowable by your Persistence class.

score 0 · Answer 4 · answered Oct 22 '12 at 05:19

0

In PHP, overloading is only for properties and not as you might be used to from other languages. You could overload __call and __callStatic, but it is simpler to employ inheritance.

answered Oct 22 '12 at 05:19

Burhan Khalid

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score 0 · Answer 5 · answered Oct 22 '12 at 05:20

PHP does not have typed parameters, so you wouldn't be able to do it like in your example. You could pass in a second parameter with the type however and use that within the function:

function add($type, $object){
    if ($type=="user"){
       // process $object as a user
    } elseif ($type=="group"){
       // process $object as a group
    }
}

define multi function with same name and different argument type in PHP

5 Answers5