Static methods in PHP OOP

In this tutorial we will learn more about the static methods in PHP OOP. We will discuss what static methods are meant for, when to use them, the syntax and the difference between static and non-static methods.

What are static methods in PHP?

• Static methods are created using static keyword.
• Static methods of a class are called directly. It means, we don’t need to create the instance of the class to call its static method.
• A class can contains both static and non-static methods.
• To call the static method of a class, we use scope resolution operator ::

Syntax of Static Method in PHP

<?php
class ClassName {
  public static function method() {
    echo "Hello from PHP!";
  }
}
?>

Syntax to call the static method

ClassName::staticMethod();

Example

<?php
class Example {
  public static function greetings() {
    echo "Hello from PHP!";
  }
}

// Calling static method
Example::greetings();
?>

• In the above example, we create a class that contains static method in it.
• We call the static method of this class outside using scope resolution method.

Calling static method inside the class – PHP

• In PHP, self keyword allows to call its own static method inside the class. Look at the following example in which we create a class with static method and call it inside the constructor of the class.
• self::methodName() is the general syntax to call static method inside the class.

<?php
class Example {
  public static function greetings() {
    echo "Hello from PHP!";
  }

  public function __construct() {
    self::greetings();
  }
}

new Example();
?>

Calling Static Method inside another class – PHP

It’s very interesting to use case of static methods, that we can call a public static method inside another class. Remember, it should be a public static method.

<?php
class Example{
  public static function greetings() {
    echo "Hello from PHP!";
  }
}

class Example2{
  public function msg() {
    Example::greetings();
  }
}
?>

Calling a static method in child class – PHP

In the case of inheritance, we can call the static method of the parent class inside the child class using the parent keyword. Look at the example below.

<?php
class Example {
  protected static function getMessage() {
    return "Message from static method";
  }
}

class Child1 extends domain {
  public $name;
  public function __construct() {
    $this->name= parent::getMessage();
  }
}

$child1= new child1();
echo $child1-> name;
?>

• In the above example, we create a parent class with some static method.
• Also, we create another class that extends the parent class.
• Call the static method of the parent class using parent keyword followed by the name of the static method.

Note: As we mentioned in the previous section that calling a static method inside another class required it to be public. However, in the case of calling the static method of the parent class (inheritance), the static method access modifier can be public or protected.

Difference between Static and Non Static Methods

Reference to the official PHP documentation of static method.