PHP Interfaces
PHP - What are Interfaces?
A interface is used to make collection of methods into a groups and to support multiple inheritence.
You can specify which methods a class should implement by using interfaces definitions.
Interfaces make it simple to use multiple classes at the same time. "Polymorphism" is a term that refers to when two or more classes share the same interfaces.
The interface keyword is used to declare interfaces in a program :
Syntax :-
<?php
interface InterfaceName {
public function someMethod1();
public function someMethod2($name, $color);
public function someMethod3() : string;
}
?> PHP - Interfaces vs. Abstract Classes
Abstract classes and interfaces are comparable. The distinction between interfaces and abstract classes is as follows :
- In contrast, abstract classes can have characteristics.
- Abstract class methods are either
publicorprotected, while interface methods are required to be public accessible. - It is not essential to use the keyword
abstractbecause all methods in an interface are abstract. - Inheritance from one class and implementation of an interface are both possible.
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PHP - Using Interfaces
A class must employ the implements keyword in order to implement an interface.
All of the methods of an interface must be implemented by a class that implements it.
Example 1 :-
<!DOCTYPE html>
<html>
<body>
<?php
interface Animal {
public function makeSound();
}
class Cat implements Animal {
public function makeSound() {
echo "Meow";
}
}
$animal = new Cat();
$animal->makeSound();
?>
</body>
</html> Output :-
Assume we want to create software that handles a group of animals based on the preceding example. There are some actions that all of the animals can perform, but each species executes it in its own unique way.
Example 2 :- We can develop code that works for all of the animals, even if they behave differently, by using interfaces :
<!DOCTYPE html>
<html>
<body>
<?php
// Interface definition
interface Animal {
public function makeSound();
}
// Class definitions
class Cat implements Animal {
public function makeSound() {
echo " Meow ";
}
}
class Dog implements Animal {
public function makeSound() {
echo " Bark ";
}
}
class Mouse implements Animal {
public function makeSound() {
echo " Squeak ";
}
}
// Create a list of animals
$cat = new Cat();
$dog = new Dog();
$mouse = new Mouse();
$animals = array($cat, $dog, $mouse);
// Tell the animals to make a sound
foreach($animals as $animal) {
$animal->makeSound();
}
?>
</body>
</html> Output :-
Example Explained :-
The Animal interface is implemented by Cat, Dog, and Mouse, therefore they can all generate sounds with the makeSound() method. As a result, even if we don't know what kind of animal each one is, we can loop through all of them and order them to create a sound.
A method's implementation is not specified in the interface, which means that each animal's sound is unique.
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