# RecursiveFilterItrator possible issues with inheritance - Thread: https://externals.io/message/43862 - Original archive: https://news-web.php.net/php.internals/43862 - Started by Ralph Schindler on 2009-05-06T15:16:19+00:00 - Messages: 3 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #43862 — Ralph Schindler — 2009-05-06T15:16:19+00:00 URL: https://externals.io/message/43862#43862 Hi all, I'd like to confirm something as a bug and/or design issue. Currently, its difficult to extend RecursiveFilterIterator() with additional __construct() arguments (for configuring its behavior). The reason its difficult is b/c when getChildren() is called, a new instance of the RFI is created (only way you'd know this is if you look into the source of RFI). Ideally, this code would work: $rArray = array('a' => array('ab', 'ac', 'ad' => array('ada', 'adc')), 'b' => array('bb', 'bc')); $ri = new RecursiveArrayIterator($rArray); $filter = new MyRFI($ri, 'argument'); $iterator = new RecursiveIteratorIterator($filter); foreach ($iterator as $key => $item) { echo $key . ' - ' . $item . PHP_EOL; } class MyRFI extends RecursiveFilterIterator { protected $_otherArg = null; public function __construct($iterator, $otherArg = null) { $r = new ReflectionClass($this); $this->_otherArg = $otherArg; parent::__construct($iterator); } public function accept() { echo ($this->_otherArg) ? 'Arg Present' : 'Arg NOT Present'; echo PHP_EOL; return true; } The current output would be: ~/tmp/test-rii-filter$ php test-rii-problem.php Arg Present Arg NOT Present 0 - ab Arg NOT Present 1 - ac Arg NOT Present Arg NOT Present 0 - ada Arg NOT Present 1 - adc Arg Present Arg NOT Present 0 - bb Arg NOT Present 1 - bc The ideal output would be: Arg Present Arg Present 0 - ab Arg Present 1 - ac Arg Present Arg Present 0 - ada Arg Present 1 - adc Arg Present Arg Present 0 - bb Arg Present 1 - bc The only proposed change I could would be to make the getChildren() inside of RecursiveFilterIterator use clone & add a method called setIterator() instead of Reflection::newInstance($iterator) Is this possible? Or is extending and overriding getChildren() the best strategy here? Reason I post is b/c it seems like using clone/setIterator() would facilitate better inheritance / better polymorphism. And since the implementation is in the extension, the typical developer would generally not understand how getChildren() really works under the hood. Thanks, Ralph --- ## #43863 — Etienne Kneuss — 2009-05-06T15:35:46+00:00 URL: https://externals.io/message/43862#43863 · In reply to: #43862 Hello, > Hi all, > > I'd like to confirm something as a bug and/or design issue. This is a bug, could you please report it and assign it to me ? Thanks, > > Currently, its difficult to extend RecursiveFilterIterator() with additional > __construct() arguments (for configuring its behavior). The reason its > difficult is b/c when getChildren() is called, a new instance of the RFI is > created (only way you'd know this is if you look into the source of RFI). > > Ideally, this code would work: > > > $rArray = array('a' => array('ab', 'ac', 'ad' => array('ada', 'adc')), 'b' > => array('bb', 'bc')); > > $ri = new RecursiveArrayIterator($rArray); > $filter = new MyRFI($ri, 'argument'); > $iterator = new RecursiveIteratorIterator($filter); > > foreach ($iterator as $key => $item) { > echo $key . ' - ' . $item . PHP_EOL; > } > > class MyRFI extends RecursiveFilterIterator > { > protected $_otherArg = null; > > public function __construct($iterator, $otherArg = null) > { > $r = new ReflectionClass($this); > $this->_otherArg = $otherArg; > parent::__construct($iterator); > } > > public function accept() > { > echo ($this->_otherArg) ? 'Arg Present' : 'Arg NOT Present'; > echo PHP_EOL; > return true; > } > > > The current output would be: > > > ~/tmp/test-rii-filter$ php test-rii-problem.php > Arg Present > Arg NOT Present > 0 - ab > Arg NOT Present > 1 - ac > Arg NOT Present > Arg NOT Present > 0 - ada > Arg NOT Present > 1 - adc > Arg Present > Arg NOT Present > 0 - bb > Arg NOT Present > 1 - bc > > > The ideal output would be: > > Arg Present > Arg Present > 0 - ab > Arg Present > 1 - ac > Arg Present > Arg Present > 0 - ada > Arg Present > 1 - adc > Arg Present > Arg Present > 0 - bb > Arg Present > 1 - bc > > > > > The only proposed change I could would be to make the getChildren() inside > of RecursiveFilterIterator use clone & add a method called setIterator() > instead of Reflection::newInstance($iterator) > > Is this possible? Or is extending and overriding getChildren() the best > strategy here? > > Reason I post is b/c it seems like using clone/setIterator() would > facilitate better inheritance / better polymorphism. And since the > implementation is in the extension, the typical developer would generally > not understand how getChildren() really works under the hood. > > Thanks, > Ralph > > > > > -- > > > > -- Etienne Kneuss http://www.colder.ch Men never do evil so completely and cheerfully as when they do it from a religious conviction. -- Pascal --- ## #43865 — Etienne Kneuss — 2009-05-07T00:37:43+00:00 URL: https://externals.io/message/43862#43865 · In reply to: #43863 Hello, > Hello, > > > > […] > > This is a bug, could you please report it and assign it to me ? > > Thanks, > > > […] Sorry for the false hope, it is indeed how it's supposed to work and not a bug. Since the new iterator is instanciated directly inside getChildren, you can't magically have new arguments to your constructor and have them filled appropriately. But you can basically implement all features you want by simply overriding getChildren. Clone + setiterator could also work, but changing that would introduce BC breaks, and I'm not sure it would make more sense than what we have now. Regards > > […] > > > > -- > Etienne Kneuss > http://www.colder.ch > > Men never do evil so completely and cheerfully as > when they do it from a religious conviction. > -- Pascal > -- Etienne Kneuss http://www.colder.ch Men never do evil so completely and cheerfully as when they do it from a religious conviction. -- Pascal