Building A Generic Error Reporting Class In PHP - Back To Class (
Page 2 of 9 )
Before we begin, let's just
go over the basics quickly:
In PHP, a "class" is simply a set of program statements which perform a specific
task. A typical class definition contains both variables and functions, and serves
as the template from which to spawn specific instances of that class.
Once a class has been defined, PHP allows you to spawn as many instances of the
class as you like. These instances of a class are referred to as "objects". Each
of these instances is a completely independent object, with its own properties
and methods, and can thus be manipulated independently of other objects.
This comes in handy in situations where you need to spawn more than one instance
of an object - for example, two simultaneous database links for two simultaneous
queries, or two shopping carts. Classes also help you to separate your code into
independent modules, and thereby simplify code maintenance and changes.
A class definition typically looks like this:
<?php
class ShoppingCart
{
// this is where the properties are defined
var
$items;
var $quantities;
var $prices;
...
// this is where the methods are
defined
function validate_credit_card()
{
// code goes here
}
...
}
?>
Once the class has been defined, an object can be spawned with the "new" keyword
and assigned to a PHP variable,
<?php
$myCart = new ShoppingCart;
?>
which can then be used to access all object methods and properties.
<?php
// accessing properties
$myCart->items = array("eye of newt", "tongue
of frog", "wing of bat",
"hair of dog"); $myCart->quantities = array(4, 2, 11,
1);
// accessing methods
$myCart->validate_credit_card();
?>
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