PHP OOP Quick How-To

how2.php

<?php

class MyTestClass
{
    private $privateVar = array();
    protected $protectedVar;
    public $publicVar;
    
    public static $staticVar = 'boom.';
    
    /**
     * This "magic" method is run when a object of this type is instantiated.
     * @param   $privateVar   variable that can be injected on construct to bypass private accessor. Defau
     */
    __construct(array $privateVar = null)
    {
        // Only set $privateVar if it is set on construct.
        if (!is_null($privateVar)) {
            $this->privateVar = $privateVar;
        }
        
        $this->runsAfterInit(4);
    }
    
    /**
     * This method cannot be changed in extended classes because it is final.
     * It can only be accessed from this instance of MyTestClass because it is private.
     * It will be called when this class is constructed.
     */
    final private function runsAfterInit(int $number)
    {
        echo __METHOD__."\r\n";
    }
    
    protected function getClassVariables()
    {
        return array($this->privateVar, $this->protectedVar, $this->publicVar);
        
    }
    
    public function getPublicVar()
    {
        return $this->publicVar;
    }
    
    public function getPrivateVar()
    {
        return $this->privateVar;
    }
    
    public function getProtectedVar()
    {
        return $this->protectedVar();
    }
    
    public function setPrivateVar($privateVar)
    {
        $this->privateVar = $privateVar;
        return $this;
    }
    
    public static setStaticVar($staticVar)
    {
        self::$staticVar = $staticVar;
    }
}

class MyExtendedTestClass extends MyTestClass
{
    
    private $privateVar = 'extended';
    
    protected function getClassVariables()
    {
        return array($this->privateVar, $this->protectedVar, $this->publicVar);
        
    }
    
}

$testClass = new MyTestClass();

// Prints array()
print_r($testClass->getPrivateVar());

$extendedTestClass = new MyExtendedTestClass();

// Prints 'extended'
print_r($extendedTestClass->getPrivateVar());

$testClass->setPrivateVar('Test');

// Prints 'extended'
print_r($extendedTestClass->getPrivateVar());

// Prints 'boom.'
print_r(MyTestClass::getStaticVar());

MyTestClass::setStaticVar('statiiic');

// Prints 'statiiic'
print_r(MyExtendedTestClass::getStaticVar());


// Never use closing php tags. Causes crazy headaches with header output and such.