Facade is a structural design pattern that provides a simple and unified interface to a large subsystem of objects. It defines a high-level interface that makes the subsystem more accessible and convenient to use.
The example below demonstrates how to implement a Facade in PHP. Let's imagine that we have a system for sending messages through various channels (email, SMS, etc.).
<?php
// Subsystem for working with email
class EmailSubsystem
{
public function sendEmail($to, $message)
{
echo "Sent an email to address $to: $message\n";
}
}
// Subsystem for working with SMS
class SMSSubsystem
{
public function sendSMS($number, $message)
{
echo "Sent SMS to number $number: $message\n";
}
}
// Facade to simplify subsystem usage
class NotificationFacade
{
private $emailSubsystem;
private $smsSubsystem;
public function __construct()
{
$this->emailSubsystem = new EmailSubsystem();
$this->smsSubsystem = new SMSSubsystem();
}
// Method for sending notifications via email
public function sendEmailNotification($to, $message)
{
$this->emailSubsystem->sendEmail($to, $message);
}
// Method for sending notifications via SMS
public function sendSMSNotification($number, $message)
{
$this->smsSubsystem->sendSMS($number, $message);
}
}
// Using the facade
$notificationFacade = new NotificationFacade();
$notificationFacade->sendEmailNotification('user@example.com', 'Hello, this is your email notification!');
$notificationFacade->sendSMSNotification('123456789', 'Hello, this is your SMS notification!');
?>
In this example, the `NotificationFacade` serves as a higher-level interface for sending notifications, abstracting the details of working with email and SMS subsystems.
