Calling an Overridden Method in OOP in PHP

When overriding, the child loses access to the overridden method of the parent. However, it is still possible to access it. This is done using the keyword parent, which refers to the parent class.

Let's look at an example when we might need access to the parent method. Suppose we have the following parent class:

<?php
	class User {
		private $name;
		
		public function setName($name) {
			$this->name = $name;
		}
		public function getName() {
			return $this->name;
		}
	}
?>

Suppose we in the child class overrode the parent method:

<?php
	class Student extends User {
		public function setName($name) {
			if (strlen($name) > 0) {
				$this->name = $name;
			} else {
				echo 'student name error';
			}
		}
	}
?>

It can be noticed that in the overridden method, when the condition is met, essentially the code of the parent method is executed. This results in unnecessary code duplication.

We can get rid of it by calling the parent method. Let's do this:

<?php
	class Student extends User {
		public function setName($name) {
			if (strlen($name) > 0) {
				parent::setName($name); // parent method
			} else {
				echo 'student name error';
			}
		}
	}
?>

Given the following code:

<?php
	class User {
		private $age;
		
		public function setAge($age) {
			if ($age >= 0) {
				$this->age = $age;
			} else {
				echo 'need age more 0';
			}
		}
	}
	
	class Employee extends User {
		public function setAge($age) {
			if ($age <= 120) {
				if ($age >= 0) {
					$this->age = $age;
				} else {
					echo 'need age more 0';
				}
			} else {
				echo 'need age less 120';
			}
		}
	}
?>

In the Employee class, fix and simplify the age setter by using the original parent method.