PHP Class Access Control Modifiers
In this chapter you will learn:
Description
Access control modifiers can place before a class, a method definition, or a property to alter the way PHP treats them.
List of Access Control Modifiers
| Access Modifiers | Meaning |
|---|---|
| Public | Set property or method to be accessible from anywhere |
| Private | Set property or method to be accessible only by its own class or object |
| Protected | Set property or method to be accessible by its class or by its descendants |
| Final | Set property, method, or class cannot be overridden in subclasses |
| Abstract | Set method or class cannot be used directly. We have to subclass it. |
Most of the variables in a class should be marked as either protected or private.
Public
Public properties and methods are accessible from anywhere.
<?PHP// j a v a2s.co m
class Book {
public $Name;
public function say() {
print "PHP!\n";
}
}
class PythonBook extends Book {
public function say() {
print "Python!\n";
}
}
$aBook = new PythonBook;
$aBook->Name = "Python";
print $aBook->Name;
?>
By default, all class methods are public.
The code above generates the following result.
Private
Private properties are accessible only inside its own the class.
<?PHP/*from jav a 2 s .c o m*/
class Book {
private $Name;
private $NameTag;
public function setName($NewName) {
// etc
}
}
?>
Child classes cannot access private parent methods and properties. If you want to do this, you need the protected keyword instead.
Protected
Protected properties and methods are accessible within its owns class and a child class. Consider the following code:
<?PHP/*from j av a 2s.c o m*/
class Book {
public $Name;
protected function getName() {
return $this->Name;
}
}
class Poodle extends Book {
public function say() {
print "'Book', says " . $this->getName();
}
}
$aBook = new Poodle;
$aBook->Name = "PHP";
$aBook->say();
?>
The code above generates the following result.
Next chapter...
What you will learn in the next chapter:
- What is a constructor
- Syntax to create a constructor
- Example - Class with a constructor
- Example - Constructor with arguments
- Example - Parent Constructors