PHP Object-Oriented Programming (OOP)

Polymorphism is an object-oriented programming concept that can be difficult to understand. This article, the first of a three-part series, walks you through the basics of Polymorphism so that you can make use of it in your own applications. The specific example in this article will show you how to use it with different database systems.

If you re starting to delve deeper into object-oriented programming with PHP, and also want to know how to include polymorphic objects into your own scripts, this might be the right opportunity to learn more about this interesting topic. Welcome to the second part of the series that began with Using polymorphism with objects in PHP 5. In three articles, this series provides you with a comprehensive guide on how to take advantage of polymorphism...

Welcome to part two of the series Building Object-Oriented Database Interfaces in PHP. In the previous article, I offered complete coverage of the role that database interfaces play in Web applications, highlighting the immediate benefits of having a centralized mechanism for accessing, processing and verifying data, within an object-oriented environment. The DBIGenerator class I showed for demonstration purposes in the first article doesn t ...

With websites now featuring full-blown dynamic applications that link to databases, data accessing has become a critical process. Often, an object-oriented solution is wanted to manage the data access operations. This works well, except when certain statements are hard-coded in that can cause headaches when a update is required. Alejandro Gervasio explains how a new category of tools, known as database interfaces, help to solve this problem.

In this fourth and final article in the tutorial series, Alejandro Gervasio updates the DBIGenerator class developed in the previous articles. The new version incorporates features in PHP 5, such as member visibility, exceptions, and other useful items.

In previous articles in this series, we examined the concept of database interfaces, and saw source code for a DBIGenerator class. Working with multiple DB interfaces permits the accomplishment of several operations on many tables at the same time. Alejandro Gervasio demonstrates the power of this concept, with examples.

In this article, we work directly with a standalone caching class, showing how it interacts with other objects. We will work with aggregation and composition to achieve our goals, which include implementing a time expiry based caching mechanism.

Mastering some of the most popular design patterns with PHP 5 can be sometimes an overwhelming process that requires hard work and experience. However, if you want to tackle the challenge and expand your existing background on them, this article might eventually find a place on your quick reference list.

The abstract factory pattern can be useful if you re developing a PHP application that needs to create diverse objects in multiple contexts. If you re interested in learning the basics of this design pattern, this set of articles might be what you re looking for. Welcome to the second installment of the series Using abstract factory classes in PHP 5. In a step-by-step guide, this series teaches you how to create abstract factory classes in PHP ...

When you are writing an object-based web application in PHP, you want to prevent your classes from being convoluted with input objects of the incorrect type. These input objects can cause the application to throw a fatal error. In this article, you will learn how to enforce object types in PHP 4.

This is the second installment of the series Enforcing object types in PHP. Welcome back. As you ll surely know, this three-part series goes through the basic concepts of object type enforcement in PHP 4/PHP 5. It explores different approaches for checking types of objects to help you avoid possible code contamination when objects of incorrect type are inputted within PHP classes.

Here we are again. Welcome to the last tutorial of the series Enforcing object types in PHP. As this article s title suggests, this series introduces the basics of object type enforcement in PHP, covering some of the most common methods for checking types of objects in both PHP 4 and PHP 5 respectively.

Has your career as PHP developer led you to learn more about the most popular design patterns? If it has, then this series may help you get a better grounding in them. Welcome to the second installment of the series Introducing Visitor Objects in PHP 5. Made up of three articles, this series introduces the key points of how to apply the visitor pattern in PHP, and emphasizes the practical side of the topic by walking you though copious hands-on...

The object-oriented paradigm includes the ability to overload classes; not surprisingly, this is possible in PHP. In this first part of a series, you will learn how to implement class overloading in PHP 4, specifically using the overload() function, which comes in handy for triggering __set() and __get() methods when a property access is overloaded.

Object Oriented Programming (OOP) is a powerful technology for designing Web applications. This article is the first in a three part series that will explain two of the bases of OOP, Inheritance and Polymorphism, and apply these principles to building an extensible form generator.

In part two of this three-part series, we refresh our memory of Inheritance and subclasses from part one, and take our first stab at implementing a form generator.

In the last part of this three-part series of articles, we will find out how to improve the form generator we created in part II by learning about Polymorphism and adding it to the mix.

Before I start anything, I d like to acknowledge the work of Alain M. Samoun. His articles on phpBuilder.com and phpclasses.org were fundamental in figuring out how to interface to COM componentry, so thank you VERY much Alain! The steps being followed in this tutorial are: Check pre-requisites Check and modify php.ini settings. Modify COM permissions to allow PHP to use the COM interface Modify the applications COM permissions to allow the use ...

In this article, the first of a three-part series, you will be introduced to the basics of creating directors and builder objects with PHP 5. As usual, there will be copious examples to help you quickly start using the builder pattern in your own PHP projects.

This article, the first of three parts, introduces you to the chain of responsibility pattern in PHP 5. This pattern is useful when a specific class cannot deal with a particular task, and must therefore transfer a program s execution to another class with the appropriate capability.

Although the article s title may seem a bit intimidating, the truth is that things are much simpler than you think. Like many other programming languages, PHP also allows you to construct and use visitor objects with minor hassles. But, before I go deeper into the subject, first let s ask ourselves the following question: what are visitor objects, after all?

In this article, the first part of a series, you ll learn the basics of applying the command pattern with PHP 5. As always, plenty of hands-on examples are included.

Welcome back! Last time we met, I discussed with you the concept of using multiple files to store your PHP scripts. // ); //]] In today s column, I ll be introducing one of the more interesting and useful methods of writing PHP scripts -- the object-oriented method. Those of you who might have experience with an object-oriented programming language such as Java or even C++ will find themselves right at home with most of the concepts I ll begin o...

Welcome back! In my last column I introduced to you the concept of classes in PHP and provided you with some basic examples for writing your scripts in an object-oriented way. This week, I ll discuss the concept of objects in more detail, including some of the more powerful features (and the main reason to use objects) such as inheritance and using objects as data-storage containers. Let s get started. Object Hierarchies One of the most powerful ...

One of the most common tasks that I came across developing interactive websites was processing users input. In this article I would like to share the experience I had developing an object-oriented solution for it. The best effect that I can imagine this paper to have is to not just show “another solution for checking a submitted form”, but rather to let you taste the power of object-oriented technology. Together with you, I will look b...

Are you one of those PHP developers who wants to expand your background in design patterns by learning an additional one? If your answer is affirmative, then this series might be appealing to you. It will teach you, in three educational tutorials, how to create and implement command objects with PHP 5.

Are you looking for an approachable guide on how to use the mediator design pattern in PHP 5? If you answered yes, then you should take a look at this group of articles. Welcome to the final part of the series that began with Introducing Mediator Classes in PHP 5. This series takes you through building mediator classes with PHP, and shows you how to use this useful pattern with copious code samples.

Aggregation in PHP allows one object to use another object. It s a very powerful concept. This article, the first in the series, serves as an introduction to some of the things you can do with aggregation.

In this second part of his series, Alejandro Gervasio gets a little more technical with the basics of Aggregation. He begins working with a MySQL abstraction class and a useful paging class, and is starting to get into writing portable code and introducing the technique of aggregation.

In the third part of his series, Alejandro Gervasio digs a bit further into object-oriented PHP. He explains the barebones of a paging class and techniques used to aggregate a new MySQLConnector class.

In the fourth and final article in our series covering aggregation in PHP, Alejandro Gervasio reviews the MySQLConnector and Pager classes. He then uses these classes first to build a simple database, then to display some paged results from the database.

Composition is an important concept in PHP. It occurs when an object creates another object; that is, the first object completely possesses the second object. In this article (the first of two parts), Alejandro Gervasio explains composition, and shows some examples to illustrate his points.

In the first article of this series, the concept of composition in object-oriented programming was explained, and illustrated with an example that implemented composition using two simple classes. In this article, we will create a MySQL database wrapping class that uses the concept of composition.

This chapter is excerpted from Object-Oriented PHP: Concepts, Techniques, and Code from NoStarch Press. PHP 3 was released in mid-1998. Some basic object-oriented (OO) capabilities were included, more or less as an afterthought, to provide new ways of accessing arrays.1 No significant changes were made to the object model when version 4 was released in mid-2000. The basics of object-oriented programming (OOP) were there--you could create a clas...

OK, so you ve heard all about it, you think you ve got your head around it. Everyone you speak to says it s the way real developers develop. How do you do it? What s in it for you? And how the hell do you do it with PHP? Broadly speaking, all of the above statements are true, but I guess if you re not familiar with OO you want to see a concrete example - and ideally something, which you can fit into your own page(s). Well, here goes. Let s start...

This arcticle introduces Object Oriented Programming (OOP) in PHP. I will show you how to code less and better by using some OOP concepts and PHP tricks. Good luck! Concepts of object oriented programming: There re differences between authors, I can mention that a OOP language must have: Abstract data types and information hidding Inheritance Polymorphism The encapsulation is done in php using classes: ?phpclass Something { ...

If you re looking for an overview of the new object-oriented features of PHP 5, you ve found a good place to start. This article, the first of several parts, is excerpted from chapter two of the book

A fine implementation of the object-overloading paradigm has found its way into PHP version 5. This article explores the possibilities of the overload methods __call(), __set(), and __get(). After explaining the basic theory of overloading, it dives straight into the topic by using two practical examples: first, implementing persistable classes, and second, figuring out a way to realize dynamic getter and setter methods. If you do not yet know wh...

PHP has evolved into a feature-rich, widely deployed web development solution. With each new version released, new features appear, while existing features are improved. PHP s object support is one such feature that has been improved. Object oriented support first appeared in PHP3. PHP4 made additional improvements, such as the way constructors are handled. In fact, the up and coming Zend Engine 2.0 introduces a new object model, more similar to...

Last week, we discussed design patterns and polymorphism. This week, we examine overloading and more. This article, the last of four parts, is excerpted from chapter two of the book

Welcome to the last installment of the series Overloading classes in PHP. Comprised of three tutorials, this series shows you how to overload your classes whether you re using PHP 4 or PHP 5, and explains in detail the implementation of the __set() , __get() and __call() methods, in order to overload property accesses and method calls respectively.

This article explains what polymorphism is and how it applies to object oriented design in particular. It also explains the pros and cons of polymorphism when working with certain versions of PHP.

This article continues a series on PHP5 OOP. In the first article, PHP 5 OOP: Interfaces Abstract Classes and the Adapter Pattern, I presented an interface for abstracting database access from the actual database. In the second article, PHP 5 OOP: Protecting Data With Visibility , I showed how to expand upon the functionality built in the first article in order to show how to protect your data using visibility modifiers. In this article you will ...

PHP 5 made significant improvements on the Object Orientated programming model of PHP 4 bringing it more in line with languages such as Visual Basic .NET and Java. The improved object model in PHP 5 makes developing applications using OOP much easier and gives you the programmer, greater flexibility. In this series of articles I will demonstrate the new features of the PHP 5 object and show you how to create a database abstraction layer similar t...

This article continues the discussion of using PHP to create a database abstraction layer by using the OOP features of PHP. In the prior article, PHP 5 OOP: Interfaces Abstract Classes and the Adapter Pattern, I presented an interface for abstracting database access from the actual database. The article also presented code for accessing a database. In this article you will learn to expand upon the functionality you built from the first article in...

This article concludes a series on PHP5 OOP. In the first article, PHP 5 OOP: Interfaces Abstract Classes and the Adapter Pattern, I presented an interface for abstracting database access from the actual database. In the second article, PHP 5 OOP: Protecting Data With Visibility, I showed how to expand upon the functionality built in the first article in order to show how to protect your data using visibility modifiers. In the third article, ...

All web developers will at some point need to program their own form. Whether it is for database submission, emailing, or for some other purpose, forms represent the primary means of enabling a user to send data to an application. As a result, it is important to have control over the data collected by your forms, which will aid in the creation of streamlined, error-free applications. Assumptions This article assumes the reader has some prior kno...

Last week, we continued our discussion of the object-oriented features of PHP 5 by taking a first look at design patterns. This week, we will continue looking at design patterns, and examine polymorphism. This article, the third of four parts, is excerpted from chapter two of the book

You may have already encountered situations in coding PHP applications in which you would like to use inheritance, but could not for one reason or another. Fortunately, there is an alternative for these situations that can help you achieve the same result. In this first article in a two-part series, you ll learn about the adapter pattern.

Object serialization in PHP is very easy, and can be used for a variety of different purposes. It can be used to perform some fairly complex operations, in fact. This article, the first of a three-part series, introduces you to object serialization and a number of the tasks for which you can put this approach to use.

We all know how to fetch a row from MySQL, read the data, and save some data back. It s fairly simple and straightforward, with nothing tricky is going on behind the scenes. However, there is much to be gained by using an OOP approach to managing data in your database. This article is a sketch of how one might design an Object-Oriented approach to managing records in a database. All the logic inherent in your data can be encapsulated into discre...

While PHP 4 was the first version to offer Object-Oriented Programming (OOP) capabilities, many considered the feature to be poorly designed and more an afterthought than anything else. PHP 5 resolves many of the version 4 OOP inconsistencies, not to mention greatly enhances the language s object-oriented capabilities. While you re still free to program using a procedural methodology, those of you with object oriented backgrounds will certainly f...

There seems to be a common pitfall among some PHP developers--especially those just beginning PHP programming--and that is their lack of object-oriented (OO) PHP use. This article s purpose is to inform developers about the practicality of OO PHP; fully understanding the benefits of using OO PHP should be a requirement in the PHP learning process. Pitfall Among Developers I myself experienced the pitfall in the beginning of my PHP enlightenment, ...

Experienced PHP programmers know that web development problems are often tackled by using widely known design patterns within the context of an application. This article is the first in a series that will demonstrate how the Singleton and Factory patterns can be implemented in a real-world application.

If you re a PHP programmer who s searching for a comprehensive tutorial on how to create adapter classes with PHP 5, them look no further. Welcome to the final installment of the series Implementing adapter objects with PHP. Made up of two parts, this series teaches you how to implement the adapter design pattern in PHP 5, and it accompanies the corresponding theory with educational examples.

If you are working with classes in PHP, you will sooner or later encounter inheritance, polymorphism, and serialization. The ability to use these three will help speed up your code writing. This article covers how to use them, and more.

This is part two of the series Overloading classes in PHP. In three tutorials, this series teaches how to overload your classes in PHP 4 by using the overload() PHP built-in function, in conjunction with the implementation of the __set() , __get() and __call() methods, and explores the native support of object overloading in PHP 5.

If you were looking for an approachable guide on how to create and use command objects with PHP 5, then look no further, because your search is over. Welcome to the final part of the series Creating command objects with PHP 5. Comprised of three comprehensive tutorials, this series walks you through the basics of how to apply the command pattern in PHP, and it accompanies its corresponding theory with numerous code samples.

Here you have it. The tutorial that you were waiting for! Welcome to the concluding part of the series Maintaining the state of applications with PHP sessions. In several tutorials, this series goes through the key points of managing sessions in PHP, and explores some of their most advanced features, such as developing user-defined session storage modules and using session handling objects.

Curious about how to serialize your objects inside your beautifully-crafted application? Look no further. Welcome to the second part of the series Serializing objects in PHP. This set of three tutorials introduces the fundamentals of objects serialization, and teaches you some advanced concepts regarding this approach, such as using objects in sessions and storing them in database tables.

If you re looking for brand new material to help you expand your background in using design patterns with PHP 5, then hopefully this article will suit your needs. Welcome to the final installment of the series Introducing Visitor Objects in PHP 5. Composed of three chapters, this series walks you through the key points of creating and using visitor objects with PHP 5, and teaches you how to use them in the context of real-world applications.

If you re a PHP developer who wants to learn how to take advantage of polymorphism to build more efficient and robust object-oriented applications, then this group of articles might be what you need. Welcome to the final part of the series that started with Using Polymorphism with Objects in PHP 5. Comprised of three tutorials, this series shows you how to create polymorphic classes with PHP; it also teaches you how to use them in rea...

My real job involves working with J2EE applications at this time. It pays the bills. I ve worked with ASP in the past and have recently (2003) gotten more into working with PHP. Most of my sidework these days is data driven PHP/MySQL web sites. It s unfortunate that sidework doesn t pay the bills, because I have found PHP to be a very powerful programming platform. My attempt here is to apply some principles and concepts that I have learned in m...

If you re interested in learning how to combine objects, sessions and MySQL, this is the article that you ve been waiting for. It s the final part of the series Serializing objects in PHP. In three parts, this series goes through the fundamentals of serializing objects in PHP applications, and explores some advanced topics with regard to this subject, including the use of the magic __sleep() and __wakeup() functions, and the manipulation of...