ZEND PHP 5 Certification STUDY GUIDE

Elements of Object-oriented Design ” 179
class myData implements Iterator {
private $myData = array(
"foo",
"bar",
"baz",
"bat");
private $current = 0;
function current() {
return $this->myData[$this->current];
}
function next() {
$this->current += 1;
}
function rewind() {
$this->current = 0;
}
function key() {
return $this->current;
}
function valid() {
return isset($this->myData[$this->current]);
}
}
$data = new myData();
foreach ($data as $key => $value) {
echo "$key: $value\n";
}
This example will iterate over each of the four elements in the myData private property
in the exact same way foreach() works on a standard Array.
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)
Seekable Iterators
The next step up from a standard Iterator is the SeekableIterator, which extends
the standard Iterator interface and adds a seek() method to enable the ability to
retrieve a specific item from internal data store. Its interface looks like this: