Wes Shell has posted a new tutorial to his blog today looking at encapsulation in PHP development - containing parts of the script to make them easier to work with as a whole.

In order to understand the purpose of encapsulation you first need to understand the purpose of classes. [...] In order for them to be used properly as they were designed, you will need to limit how users of the class can interact with those characteristics and functionality.

He looks at the visibility modifiers (public/private/protected), interface functions and some sample code showing how to use them in a simple class to work with a Person's set of data.

On the Blue Parabola blog, Matthew Turland takes a look at object-oriented programming and what core concepts lie at its heart.

What is object-oriented programming? The acronym OOP has become a bit of a buzzword in the current age of programming, to the point where the waters of its definition have become rather murky. [...] PHP may not be object-oriented, but from a purist perspective, neither is Java. What do I mean by "purist perspective?" Plain and simple: everything is either an object or a message being passed between objects (where message parameters are also objects).

He mentions one of the first languages to support objects (Simula) and the four fundamental concepts that would make a language truly OOP - abstraction, inheritance, encapsulation, polymorphism. Its his opinion, though, that while its good for languages to adhere to these four principles as much as they can, discussions about how well they adhere to them is usually just "spinning your wheels" and don't have much use.

Alex Netkachov has posted his own response to this opinion on the Typical Programmer on getters and setters in object-oriented applications.

"Do not use getters and setters" looks like a hastily advise, but its meaning is very important and it is "do not break encapsulation", which moves us to the question what the encapsulation is.

He notes that encapsulation is, in essence, hiding parts of the code away so that the user/other coders only see a little bit of the magic that happens. He argues that getters and setters are a valid part of the encapsulation process and that designing a good, easy to use system almost requires them.

According to this new post on the Typical Programmer blog, using getters and setters in your scripts only adds in a bit of unnecessary coupling and complexity to your scripts that you just don't need.

Today most of the popular programming languages support objects, limiting scope, modularity, passing by value, and sophisticated built-in types. There should be no reason to deliberately expose an object's data to the rest of the code because the language can enforce encapsulation and data hiding.

While not specific to PHP, the post does recommend against them because of one simple reason common to all languages that make them possible - they "break the encapsulation OOP offers". For them, they're like a cheat to get around bad coding practices and are not needed to make a successful application work.