Thursday, 18 February 2016

Access modifier in php

Access modifier in php

Restricting access to properties

  • PUBLIC
  • PRIVATE
  • PROTECTED

Those class properties and class methods which are set to be PUBLIC is accessed from any where in PHP script.I
Access:Every where

Those Class properties and class methods which are set to be PRIVATE can only be access with in the class.i.e Only the same class can access the property.

Access:This class only

Those class properties and class methods which are set to be PROTECTED can only be accessed in side a class and from its child class.i.e only the same class and classes derived from that class can access the property
Access:This Class and sub class.


public $height;
protected $social_insurance;
private $pin_number;
$abc = new User();

/* Since $pin_number was declared private,
this line of code will generate an error. Try it out! */

echo "Tell me private stuff: ".$abc->pin_number;

/* Since $pin_number was declared protected,
this line of code will generate an error. Try it out! */

echo "Tell me protected stuff: ".$abc->social_insurance;

private function get_pinn_number(){
return $this->pin_number;
}

Notes: Since the method get_pinn_number() is ‘private’, the only place you can use this method is in the same class – typically in another method. If you wanted to call/use this method directly in your PHP pages, you would need to declare it ‘public’.

example:
class MyClass
{
    public $publicProperty = 'PublicProperty';
    protected $protectedProperty = 'ProtectedProperty';
    private $privateProperty = 'PrivateProperty';

public function MyPublicMethod() { }

    // Declare a protected method
    protected function MyProtectedMethod() { }

    // Declare a private method
    private function MyPrivateMethod() { }

    // This is public
    function FooTest()
    {
        $this->MyPublicMethod();
        $this->MyProtectedMethod();
        $this->MyPrivateMethod();
    }

    function printHello()
    {
        echo $this->publicProperty;
        echo $this->protectedProperty;
        echo $this->privateProperty;
    }
}

$obj = new MyClass();
echo $obj->publicProperty; // Works fine
echo $obj->protectedProperty; // Fatal error: Cannot access protected property MyClass::$protectedProperty
echo $obj->privateProperty; // Fatal error: Cannot access private property MyClass::$privateProperty
$obj->printHello();

$myclass = new MyClass;
$myclass->MyPublicMethod(); // Works fine
$myclass->MyProtectedMethod(); // Fatal error: Call to protected method MyClass::MyProtectedMethod() from context
$myclass->MyPrivateMethod(); // Fatal error: Call to private method MyClass::MyPrivateMethod() from context

$myclass->FooTest(); // Public, Protected and Private work

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