Php Oops Static Methods

php Object-Oriented Programming (OOP) static methods with example

Accessing Static Methods:

access static methods using self::methodName()
access static methods using ClassName::methodName()
Static methods are declared static keywords.
Inside a static method that cannot use $this, there is no instance of the class.
Static methods cannot access instance methods.
Scope Resolution Operator (::):

The :: operator is used to call static methods and access static properties.

Defining Static Methods

class MyClass {
  public static function myStaticMethod() {
    return "Hello, World!";
  }
}

Calling Static Methods

echo MyClass::myStaticMethod();

Static Properties

class Math {
  public static $pi = 3.14159;

  public static function circleArea($radius) {
    return self::$pi * $radius * $radius;
  }
}
echo Math::circleArea(5);

Output:

78.53975

Inheritance and Static Methods

class ParentClass {
  public static function staticMethod() {
    return "Static method from Parent Class";
  }
}

class ChildClass extends ParentClass {}

echo ChildClass::staticMethod();

Output:

Static method from Parent Class

Static Bindings

class BaseClass {
  public static function who() {
    return __CLASS__;
  }

  public static function test() {
    return static::who();
  }
}

class DerivedClass extends BaseClass {
  public static function who() {
    return __CLASS__;
  }
}

echo BaseClass::test(); 
echo DerivedClass::test();

PHP 5.3 introduced late static bindings.

Singleton Pattern

class Singleton {
  private static $instance = null;

  private function __construct() {
    // Private constructor to prevent multiple instances
  }

  public static function getInstance() {
    if (self::$instance === null) {
      self::$instance = new self();
    }
    return self::$instance;
  }
}

$instance1 = Singleton::getInstance();
$instance2 = Singleton::getInstance();

var_dump($instance1 === $instance2);

Output:

bool(true)

Example

<?php
class MathOperations {
  // Static method to add two numbers
  public static function add($a, $b) {
    return $a + $b;
  }

  // Static method to subtract two numbers
  public static function subtract($a, $b) {
    return $a - $b;
  }

  // Static method to multiply two numbers
  public static function multiply($a, $b) {
    return $a * $b;
  }

  // Static method to divide two numbers
  public static function divide($a, $b) {
    if ($b == 0) {
      return "Cannot divide by zero";
    }
    return $a / $b;
  }
}

// Calling static methods without creating an instance of the class
echo MathOperations::add(10, 5); 
echo MathOperations::subtract(10, 5); 
echo MathOperations::multiply(10, 5);
echo MathOperations::divide(10, 5);
echo MathOperations::divide(10, 0);
?>

349