PHP iterator - run function when iteration completes

I have a iterator like this one:

http://nz.php.net/manual/en/class.iterator.php

And I was wondering how could I implement a method that runs when the objects have finished iterating.

For eg

foreach($objects a开发者_运维知识库s $object){
  ...
}
// here it's finished, and I want to automatically do something 

Example for extending an Iterator:

class Foo extends ArrayIterator
{
    public function valid() {
        $result = parent::valid();

        if (!$result) {
            echo 'after';
        }

        return $result;
    }
}

$x = new Foo(array(1, 2, 3));

echo 'before';
foreach ($x as $y) {
    echo $y;
}

// output: before123after

Extending an iterator to overload valid() is not a good approach because you are adding functionality into valid() that doesnt belong there. A somewhat cleaner approach would be to use:

class BeforeAndAfterIterator extends RecursiveIteratorIterator
{
    public function beginIteration()
    {
        echo 'begin';
    }
    public function endIteration() 
    {
        echo 'end';
    }
}

and then do

$it = new BeforeAndAfterIterator(new RecursiveArrayIterator(range(1,10)));
foreach($it as $k => $v) {
    echo "$k => $v";
}

which would then give

begin0 => 11 => 22 => 33 => 44 => 55 => 66 => 77 => 88 => 99 => 10end

Those two methods are okay to overload because they are specifically for that purpose and have no predefined behavior (mind that I'm not calling the parent method).

 function  valid(){
     $isValid=...;
     if(!$isValid)
        doStuff();
     return $isValid;
 }