When do we need Interfaces in PHP?

Posted By Bajarangi soft , Posted On 31-12-2020

Interface are definitions of the public APIs that classes (implementing an interface) must implement. It is also known as contracts as an interface allows to specify a list of methods that a class must implement. Interface definition is similar to the class definition, just by changing the keyword class to interface.

Example:

<?php
interface man {

   // List of public methods

}

Example:Interfaces can contain methods and/or constants, but no attributes. Interface constants have the same restrictions as class constants. Interface methods are implicitly abstract.

<?php

interface IMyInterface {
    const INTERFACE_CONST_1 = 1;
    const INTERFACE_CONST_2 = 'a string';

    public function method_1();
    public function method_2();
}
?>

Example: Any class that needs to implement an interface must do using the implements keyword. A single class can implement more than one interface at a time.

class MyClass implements IMyInterface {

    public function method_1() {

        // method_1 implementation
    }

    public function method_2() {

        // method_2 implementation
    }
}

Interesting Points :

A class cannot implement two interfaces that has the a same method name because it would end up with the method ambiguity.
Like classes, it is possible to establish an inheritance relationship between interfaces by using the same keyword “extends”.

Example: Any class that needs to implement an interface must do using the implements keyword. A single class can implement more than one interface at a time.

interface Foo {

}
interface Bar {

}
interface Bass extends Foo, Bar {

}

Below is a complete example that shows how interfaces work.
Example: Any class that needs to implement an interface must do using the implements keyword. A single class can implement more than one interface at a time.

<?php

// PHP program to Implement interface.

// Define a new Interface for all 'shapes'
// to inherit
interface Shape {

    // Define the methods required for
    // classes to implement
    public function getColor();
    public function setColor($color);

    // Interfaces can't define common
    // functions so we'll just define a
    // method for all implementations to
    // define
    public function describe();
}

// Define a new 'Triangle' class that
// inherits from the 'Shape' interface

class Triangle implements Shape {

    private $color = null;

    // Define the required methods defined
    // in the abstractclass 'Shape'
    public function getColor() {
        return $this->color;
    }

    public function setColor($color) {
        $this->color = $color;
    }

    public function describe() {
        return sprintf("GeeksforGeeks %s %s\n",
            $this->getColor(), get_class($this));
    }
}

$triangle = new Triangle();

// Set the color
$triangle->setColor('green');

// Print out the value of the describe common
// method provided by the abstract class will
// print out out "I am an Orange Triange"
print $triangle->describe();
?>

Related Post

How To Use Array Slice Function With Example In PHP
Why PHP Called As Loosely Typed Language In Definition
Difference Between Static Array And Dynamic Array In PHP
What Is Difference Between Traits And Interfaces In PHP
Learn How To Close A PHP Tag Inside A PHP Function
Learn How To Use OOP On Laravel PHP Framework In Laravel
Learn How To Convert SVG To PNG Files Using Jquery In PHP
When do we need Interfaces in PHP?