regarding OOP in php - php

Question

I am in the process of re educating myself in the programming of OOP
in PHP.
I have been under the erroneous assumption that all variables not static inside a class def
had to be proceeded with $this->. I finally stumbled over myself with a variable naming collision
and am now relearning, somewhat, the way of php OOP.
My present question is:
Can you mark a method property set with $this-> as public, private, or protected?
I have done;
class _DEMO
{
private $this->someVar = 'whatever';
}
and I get a syntax error.
then:
class _DEMO
{
public function __construct($_ip)
{
$this->ip = $_ip; // <<< how can I set access on this property?
}
}
As of now I don't know how to use properties with access levels set
other than to declare static properties.
OK, so I tried
class _DEMO
{
public $_someVar = 'so and so';
}
$_a = new _DEMO()
print $_a->someVar // NADA
So, I take it that the variable can be declared this way but not initialized?
on second thought, OOPs! I saw the problem with variable reference $_testy and $this->testy, should be $this->_testy
class _DEMO
{
private static $_doTell = 'Well??...';
private $_testy = "So What? ";
public function __construct($_ip)
{
$this->_testy .= " right Now?";
$this->ip = $_ip;
$this->soWhat = 'Boo!...';
}
public function getVar($_var, $_addon)
{
$this->setVar($_var, $_addon);
switch($_var)
{
case 'soWhat':
return $this->soWhat;
break;
case 'ip':
return $this->ip;
break;
case 'doTell':
return self::$_doTell;
break;
default:
break;
}
}
private function setVar($_var, $_input)
{
switch($_var)
{
case 'soWhat':
$this->soWhat .= $_input;
break;
case 'ip':
$this->ip .= $_input;
break;
case 'doTell':
self::$_doTell .= $_input;
break;
default:
break;
}
}
}
$_test = new _DEMO('Hello??...');
print "Test result 1: ".$_test->ip;
print "<br>Test result 2: ".$_test->getVar('doTell', ' So, how old are you??');
print "<br>Test result 3: \$_test::\$_doTell; Fatal error: Cannot access private property _DEMO::$_doTell";
print "<br>Test result 4: ".$_test->testy; // <<<< prints " right Now?" without errors about trying to
//access private members

Answer 1

Properties are declared at the start of the class like:
public $property1;
private $property2;
protected $property3;
Then,
1. all properties can be accessed from any method of the same class like $this->property.
2. $property1 can be accessed from all methods in ANY class.
3. $property2 can be accessed from all methods in the SAME class.
4. $property3 can be accessed from all methods in the SAME class and classes which EXTEND THE SAME class.
E.g. You can access a private property from a public method:
class A {
private $property;
public function getProperty() {
return $this->property
}
Then, in a controller, you could do:
$obj = new A;
$property = $obj->getProperty();
but not:
$obj = new A;
$property = $obj->property;

Answer 2

Sure, you can:
class MySampleClass {
/**
* #var string
*/
private $aStringVariable;
/**
* #param string $anIP
*/
protected function __construct( $anIP ) {
$this->aStringVariable = $anIP;
}
}
// How to use the class
$myClassObject = new MySampleClass( '192.168.0.1' );
You might wish to download the eval-version of PHPStorm, a PHP IDE. The IDE might help, since it points out errors while you type and PHPStorm provides auto-completion.
Additionally, have a look in the PHP Wiki of StackOverflow. The Wiki provides valuable information.

Answer 3

Here is a simple example of using property.
class HelloProperty{
private $mySimpleProperty;
public function setSimpleProperty($mySimpleProperty){
$this->mySimpleProperty = $mySimpleProperty;
}
public function getSimpleProperty(){
return $this->mySimpleProperty;
}
}
$obj = new HelloProperty();
$obj->setSimpleProperty('Hello Property');
echo $obj->getSimpleProperty();
:)