Access specifiers (or) visibility modifiers are used to control the access to properties, methods of an object.
Php support 3 access modifiers.
a. public: Any property/method defined with this access modifier can be accessed from anywhere.
b. protected: Any property/method defined with this access modifier can be accessed from this class and its subclasses.
c. Private: Any property/method defined with this access modifier can be accessed within the class only.
How to define a method with access specifiers?
‘public’, ‘protected’ and ‘private’ keywords are used to define methods with controlled access. Just prepend the method with access specifiers.
Example
public function m1(){
}
Let’s define a class with
a. One private method.
b. One public method
c. One protected method
class ParentClass{
public function i_am_public(){
echo "\nIn public method";
}
protected function i_am_protected(){
echo "\nIn protected method";
}
private function i_am_private(){
echo "\nIn private method";
}
}
Since ‘i_am_public()’ method is defined with public access specifier, you can access it outside the class, but not others.
$p1 = new ParentClass();
$p1->i_am_public();
But when you try to access protected, private methods via object from outside of the class, you will get an error.
As I said earlier, you can access a protected method from subclass.
class ChildClass extends ParentClass{
function call_super_class_methods(){
$this->i_am_public();
$this->i_am_protected();
// $this->i_am_private(); Do not run
}
}
You can access both public and protected methods from sub class, but not the private methods.
Find the below working application.
access_specifiers_demo.php
#!/usr/bin/php
<?php
class ParentClass{
public function i_am_public(){
echo "In public method\n";
}
protected function i_am_protected(){
echo "In protected method\n";
}
private function i_am_private(){
echo "In private method\n";
}
}
class ChildClass extends ParentClass{
function call_super_class_methods(){
$this->i_am_public();
$this->i_am_protected();
// $this->i_am_private(); Do not run
}
}
$p1 = new ParentClass();
$p1->i_am_public();
// $p1->i_am_protected(); Do not run
// $p1->i_am_private(); Do not run
$c1 = new ChildClass();
$c1 -> call_super_class_methods();
?>
Output
$./access_specifiers_demo.php
In public method
In public method
In protected method
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