PHP - Iterator

php_iterator.php

<?php
/**
 * Class AdsTypeCollection
 */
class AdsTypeCollection implements Iterator{

    const PANORAMA_980x120      = 'PANORAMA_980x120';
    const TOP_BANNER            = 'TOP_BANNER_930x180';
    const NETBOARD              = 'NETBOARD_580x400';
    const VERTICAL_RECTANGLE    = 'VERTICAL_RECTANGLE_240x400';

    private $position = 0;
    private $array = array(
        self::PANORAMA_980x120,
        self::TOP_BANNER,
        self::NETBOARD,
        self::VERTICAL_RECTANGLE
    );

    /**
     * AdsTypeCollection constructor.
     */
    public function __construct() {
        $this->position = 0;
    }

    /**
     *
     */
    function rewind() {

        $this->position = 0;
    }

    /**
     * @return mixed
     */
    function current() {

        return $this->array[$this->position];
    }

    /**
     * @return int
     */
    function key() {

        return $this->position;
    }

    /**
     *
     */
    function next() {

        ++$this->position;
    }

    /**
     * @return bool
     */
    function valid() {

        return isset($this->array[$this->position]);
    }

}

$adsType = new AdsTypeCollection();
while($adsType->valid()){
    echo $adsType->current().PHP_EOL;
    $adsType->next();
}

foreach($adsType as $adType){
    echo $adsType->current().PHP_EOL;
}

// Output:
/*
PANORAMA_980x120
TOP_BANNER_930x180
NETBOARD_580x400
VERTICAL_RECTANGLE_240x400

PANORAMA_980x120
TOP_BANNER_930x180
NETBOARD_580x400
VERTICAL_RECTANGLE_240x400
*/