For the past few weeks I have been working with PHP for a web application. With tons of annoyances, PHP can throw someone off balance if they are familiar with other languages.
One issue I came across, with tons of erroneous information regarding a solution, was a very simple issue of calling a parent classes constructor. For the below, I was using PHP 5.1.2 since I have been developing with PHPEclipse.
In this example, I have a base class, similar to this:
class BaseClass
{
private $_myValue;
function __construct()
{
$this->_myValue = new SomeClass();
}
}
Very simple, so I need this called in my extended class in order to initialize that myValue variable.
Now I saw some annoying solutions, which did not work, such as the below:
class DerivedClass extends BaseClass
{
private $_someOtherValuesNotInBase;
function __construct($initalizing)
{
$_ someOtherValuesNotInBase = $initalizing;
$this->BaseClass();
}
}
This didn’t work. PHP cried about not being able to find the method BaseClass(). Then I came across this little gem, which also did not work.
class DerivedClass extends BaseClass
{
private $_someOtherValuesNotInBase;
function __construct($initalizing)
{
$_ someOtherValuesNotInBase = $initalizing;
parent::BaseClass();
}
}
So, with all these erroneous solution, what is the correct answer? The following worked for me after some trial and error:
Class DerivedClass extends BaseClass
{
Private $_someOtherValuesNotInBase;
Function __construct($initalizing)
{
$_ someOtherValuesNotInBase = $initalizing;
$this->__construct();
}
}
The more I use php, the more I think it's like interpretted java at times. The syntax has definitely been heading towards such a more java-like syntax. Look at the way they do class constructors, exception handling, etc.
ReplyDeleteOn the other hand, for quick development of a website, it is amazing! A servlet can be a major pain to develop a quick form processing page, while php is easy. Further, php at times has supposedly out performed java in a number of enterprise areas, and so from a perspect of going for raw performance, it's possible php might be a better bet.
A note - I haven't used PHPEclipse - I'm still a gvim, subversion programmer. I'm surprised it didn't generate the constructor methods for you.
Did you try calling the following line from within your derived class constructor?
ReplyDelete--
parent::__construct();
--
Sure did... didn't work :|
ReplyDeleteMaybe this was fixed in a newer version, due to some external project constraints I was forced to use 5.1.2.
I'm using parent::__construct, calling it as the first thing in the derived class
ReplyDeleteclass DerivedClass extends BaseClass
{
private $_someOtherValuesNotInBase;
function __construct($initalizing)
{
parent::__construct();
$this->_someOtherValuesNotInBase = $initalizing;
}
}
also, don't forget $this-> before $_someOtherValuesNotInBase
parent::construct() ???
ReplyDelete