function Begin($action, $method='post', $name='', $id='', $style='', $class='')
The parameters all have preset default values except for the first one ($action). Some of these parameters are empty and therefore generally unused. Actually, you don’t even have to list these optional parameters in the method call if you don’t want to; they are optional in the sense that they have preset values. In this case, you must provide the
$action parameter, because it does not have a preset value. It is always good practice to have the required elements at the beginning of the parameter list. In fact, PHP won’t work very well (if at all) if the required elements are not at the front of the list. If you find your parameter lists getting too long, consider using an array or two to send them over. When looking at the generated HTML tag in the web page’s HTML, it looks like this: , so, at the very least, we will always have the required action parameter and a POST method on our tags.
Public, Protected, and Private
Just as you can set scope in procedural PHP, you can also set it in the OOP aspect of
PHP. You can identify your properties and your methods as either public, protected, or private. An entity with public scope is open to use and access outside the class definition itself. An entity with protected scope is only accessible within the class in which it is defined and its parent or inherited classes. Finally, an entity with private scope is only accessible within the class that defines it.
Encapsulation, the concept of protecting entities within a class from any outside influences, can best be achieved using the private scope attribute. A little later in this chapter, we will look at a person class to see this in action. Basically, it is always best to limit the scope access of a class from outside influences, especially if you are writing a class library that will be used in many different projects or if you are making a commercially available library. This protects your code from being tripped up in any way, either by improper use or by directly accessing its properties from outside the class itself. The protected scope is rarely used unless you have a heredity tree (inherited classes) that can benefit in some way. The public scope is the default scope if none is
68 | Chapter 6: Objects www.it-ebooks.info declared, and it is used best on methods that allow the class to interface with the outside world. The best way to share information to an outside entity that is making use of your class is with the public get and set methods (a.k.a. accessor methods) that act on