Question

I have a class and I want to be able to iterate over a certain array member. I did a quick search and found IteratorAggregate:

class foo implements IteratorAggregate {     protected $_array = array('foo'=>'bar', 'baz'=>'quux');      public function getIterator()     {         return new ArrayIterator($this->_array);     } } 

which works great, but doesn’t that create a new ArrayIterator instance every time foreach is used on it?

So I thought I should store the iterator instance in a member:

    protected $_iterator;      public function getIterator()     {         if (!$this->_iterator instanceof ArrayIterator) {             $this->_iterator = new ArrayIterator($this->_array);         }         return $this->_iterator;     } 

The problem is that the iterator uses a copy of $this->_array during the first call of getIterator(), so changes to the member aren’t reflected on subsequent foreach constructs.

I was thinking I should subclass ArrayIterator, add a setArray($array) method and call it before returning it in getIterator(), but I don’t know the member name of the array it uses internally and whether or not it’s overwriteable by a subclass.

The question is: is this a premature and/or unnecessary optimization? If no, what’s the best way to achieve this?

Answer 1

You second code will fail on multiple loops of the object where you start a new loop before another is finished.

Didnt really look like an optimization worth spending time on either.