contrived-dbresult-iterator.php

<?php

class Result {
        public $id;
        public $foo = 'bar';

        function __construct() {
                $this->id = rand(0,9999);
        }
}

class Result_Set {
        private $result_set;
        private $current_id = 0;

        function __construct($result_set) {
                $this->result_set = $result_set;
        }

        public function fetch() {
                return isset($this->result_set[$this->current_id]) ? $this->result_set[$this->current_id++] : false;
        }
}

class DB_Result implements Iterator {
        private $result_set;

        private $current_result;

        function __construct($result_set) {
                $this->result_set = $result_set;
        }

        function rewind() {
                $this->current_result = $this->result_set->fetch();
        }

        function current() {
                return $this->current_result;
        }

        function key() {
                return $this->current_result->id;
        }

        function next() {
                $this->current_result = $this->result_set->fetch();
        }

        function valid() {
                return $this->current_result !== false;
        }
}

$result_set = new Result_Set(array(
        new Result(),
        new Result(),
        new Result(),
        new Result(),
        new Result(),
        new Result(),
        new Result(),
        new Result(),
        new Result(),
        new Result()
));

$db_result = new DB_Result($result_set);

foreach($db_result as $row_id => $value) {
        var_dump($row_id);
}