CachingIterator::hasNext Example
<?php
$ait = new ArrayIterator(array('Value 1', 'Value 2', 'Value 3', 'Value 4'));
$cit = new CachingIterator($ait);
foreach ($cit as $value) {
    echo $value;
    //if has a next value, print a comma
    if ($cit->hasNext()) {
        echo ', ';
    }
}
?>
Result: Value 1, Value 2, Value 3, Value 4