PHP
  Home arrow PHP arrow Page 4 - Overloading and Object-Oriented Progr...
Administration  
AJAX  
Apache  
BrainDump  
DHTML  
Flash  
Java  
JavaScript  
Multimedia  
MySQL  
Oracle  
Perl  
PHP  
Practices  
Python  
Reviews  
Security  
Style-Sheets  
Web Services  
XML  
Zend  
Zope  
Forums Sitemap 
IBM® developerWorks 
Sun Developer Network 
E-Commerce Hosting 
Linux Web Hosting 
Managed Hosting 
Small Business Hosting 
Mobile Linux 
App Generation ROI 
VPS Hosting 
Weekly Newsletter

 
Developer Updates  
Free Website Content 
 RSS  Articles
 RSS  Forums
 RSS  All Feeds
Write For Us Get Paid 
Request Media Kit
Contact Us 
Site Map 
Privacy Policy 
Support 
 USERNAME
 
 PASSWORD
 
 
  >>> SIGN UP!  
  Lost Password? 
PHP

Overloading and Object-Oriented Programming with PHP 5
By: Sams Publishing
  • Search For More Articles!
  • Disclaimer
  • Author Terms
  • Rating: 4 stars4 stars4 stars4 stars4 stars / 9
    2006-10-12

    Table of Contents:
  • Overloading and Object-Oriented Programming with PHP 5
  • SPL and Interators
  • _ _call()
  • _ _autoload()

  • Rate this Article: Poor Best 
      ADD THIS ARTICLE TO:
      Del.ici.ous Digg
      Blink Simpy
      Google Spurl
      Y! MyWeb Furl
    Email Me Similar Content When Posted
    Add Developer Shed Article Feed To Your Site
    Email Article To Friend
    Print Version Of Article
    PDF Version Of Article
     
     
    ADVERTISEMENT


    Overloading and Object-Oriented Programming with PHP 5 - _ _autoload()


    (Page 4 of 4 )

    The final magic overloading operator we will talk about in this chapter is _ _autoload(). _ _autoload() provides a global callback to be executed when you try to instantiate a nonexistent class. If you have a packaging system where class names correspond to the files they are defined in, you can use _ _autoload() to do just-in-time inclusion of class libraries.

    If a class you are trying to instantiate is undefined, your _ _autoload() function will be called, and the instantiation will be tried again. If the instantiation fails the second time, you will get the standard fatal error that results from a failed instantiation attempt.

    If you use a packaging system such as PEAR, where the class Net_Telnet is defined in the file Net/Telnet.php, the following _ _autoload() function would include it on-the-fly:

    function _ _autoload($classname) {
    $filename = str_replace("_","/", $classname).
    '.php'; include_once $filename; }

    All you need to do is replace each _ with / to translate the class name into a filename, append .php, and include that file. Then if you execute the following without having required any files, you will be successful, as long as there is a Net/Telnet.php in your include path:

    <?php
    $telnet = new Net_Telnet;
    ? >

    Further Reading

    There are a great number of excellent books on OO programming techniques and design patterns. These are by far my two favorite design pattern books:

    • Design Patterns (by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides). This is called the "Gang of Four" book, after its four authors. This is the ultimate classic on patterns.

    • Patterns of Enterprise Application Architecture (by Martin Fowler). Fowler is an incredibly experienced fellow, and this book is an insightful and extremely practical approach to design patterns, particularly on the Web.

    Neither of these books focuses on PHP, but if you're willing to wade through C++, C#, and Python, they are well worth the effort.


    DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware.

       · This article is an excerpt from the book "Advanced PHP Programming," published by...
     

    Buy this book now. This article is excerpted from chapter two of the book Advanced PHP Programming, written by George Schlossnagle (Sams; ISBN: 0672325616). Check it out today at your favorite bookstore. Buy this book now.

       

    PHP ARTICLES

    - Working With Different Namespaces in PHP 5
    - User Management Explained: Overview
    - Using Namespaces in PHP 5
    - Database Security: Guarding Against SQL Inje...
    - Building a Modular Exception Class in PHP 5
    - Database and Password Security for Web Appli...
    - Handling MySQL Data Set Failures in PHP 5
    - Building Site Registration for Web Applicati...
    - Intercepting Customized Exceptions in PHP 5
    - Securing Your Web Application Against Attacks
    - Sub Classing Exceptions in PHP 5
    - Authentication for Web Application Security
    - Building a Content Management System with Co...
    - Filters and Login Systems for Web Applicatio...
    - Working with the Email Class in Code Igniter





    © 2003-2008 by Developer Shed. All rights reserved. DS Cluster 6 hosted by Hostway
    Stay green...Green IT