ZEND PHP 5 Certification STUDY GUIDE

Elements of Object-oriented Design ” 177
• Simple Iteration
• Seekable Iteration
• Recursive Iteration
• Filtered Iteration
Accessing Objects as Arrays
The ArrayAccess interface can be used to provide a means for your object to expose
themselves as pseudo-arrays to PHP:
interface ArrayAccess {
function offsetSet($offset, $value);
function offsetGet($offset);
function offsetUnset($offset);
function offsetExists($offset);
}
This interface provides the basic methods required by PHP to interact with an array:
• offsetSet() sets a value in the array
• offsetGet() retrieves a value from the array
• offsetUnset() removes a value from the array
• offsetExists() determines whether an element exists
As a very quick example, consider the following class, which “emulates” an array that
only accepts elements with numeric keys:
Licensed to 482634 - Amber Barrow (itsadmin@deakin.edu.au)
class myArray implements ArrayAccess {
protected $array = array();
function offsetSet ($offset, $value) {
if (!is_numeric ($offset)) {
throw new Exception ("Invalid key $offset");
}