CODEWITHSUNDEEP
phpdesign-patterns
GGio
GGio

Reputation: 7643

detect if function exists within the class and if not call a different function. PHP

I know there are other ways around this but just for the sake of simplicity I would like to know if its possible to do something like:

   MyFactory::Create()->callMe();

and myFactory class:

   class MyFactory {
       private $obj;

       public static Create() { 
           $this->obj = new ClassA();
           return $this->obj;
       }

       public function __undefinedFunctionCall() {
           //function does not exist within MyFactory Class but it exists
           // in ClassA
           $this->obj->callMe();
       }
   }

so basically the function callMe does not exist within MyFactory class but it exists in ClassA. Dont ask me why I cant just extend classA because the code structure is already written and its not up to me to modify it. I just need a way around it.

Upvotes: 3

Views: 3973

Answers (4)

Stephan
Stephan

Reputation: 1565

You could simply use method_exists

It takes 2 parameters method_exists ( mixed $object, string $method_name )

The first is an object instance or a class name, and the second is The method name.

So it should be as simple as:

if(method_exists($this->obj,'callMe')){
   $this->obj->callMe();
}
else{
//...throw error do some logic
}

Upvotes: 5

Nathan
Nathan

Reputation: 468

Your correct about using the Magic method __call(), but you are implementing it wrong.

  1. You dont need to check if it exists on its own class, PHP does this internally for you. The magic method __call only happens if the method doesn't exist.
  2. You are passing a single array argument to $this->obj->$name, where you should be passing in each argument separately.
  3. Nothing gets returned.

This is how you should implement the __call magic method for your purpose.

public function __call($name, $arguments) {
    if(method_exists($this->obj,$name)) {
        return call_user_func_array(array($this->obj, $name), $arguments);
    } else {
        throw new Exception("Undefined method ".get_class($this)."::".$name);
    }
}

Upvotes: 0

GGio
GGio

Reputation: 7643

Thanks to Mark Baker I found the solution. In case anyone else has similar problem the following solved it:

added this function inside my factory class

    public function __call($name, $arguments)
    {
            //if function exists within this class call it
        if (method_exists(self, $name))
        {
            $this->$name($arguments);
        }
        else
        {
            //otherwise check if function exists in obj and call it
            if (method_exists($this->obj, $name))
            {
                $this->obj->$name($arguments);
            }
            else 
            {
                throw new \Exception('Undefined function call.');
            }          
        }
    }

Upvotes: 1

Vahid Hallaji
Vahid Hallaji

Reputation: 7447

To checks if the class method exists or not:

$this->obj = new ClassA();
var_dump(method_exists($this->obj,'callMe'));

if it is static method:

var_dump(method_exists('ClassA','callMe'));

Returns true if the method given by method_name has been defined for the given object, false otherwise.

php.net manual

Upvotes: 0

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