Design patterns in php

Design patterns in php

Here i’m describing few of the common design patters used in php based frameworks for web development.

1.Factory

A factory is an object used to create another objects , this is a commonly used pattern.In this a class simply creates the object of another class you want to use.

eg:


 <?php
class Automobile
{
    private $vehicleMake;
    private $vehicleModel;

    public function __construct($make, $model)
    {
        $this->vehicleMake = $make;
        $this->vehicleModel = $model;
    }

    public function getMakeAndModel()
    {
        return $this->vehicleMake . ' ' . $this->vehicleModel;
    }
}

class AutomobileFactory
{
    public static function create($make, $model)
    {
        return new Automobile($make, $model);
    }
}

// have the factory create the Automobile object
$veyron = AutomobileFactory::create('Bugatti', 'Veyron');

print_r($veyron->getMakeAndModel()); // outputs "Bugatti Veyron"

2.Singleton

The concept of Singleton pattern is that restricting a class to have only one single object for it.

3.Strategy
The basic form of Strategy design pattern is achieved by taking the benefits of interface. An interface is nothing but a collection of member functions with same name in different classes with different implementations in it. In strategy design pattern interface is used as a place holder to create instances of any classes which contain the different  implementations of the methods specified in that interface so basically what happens here is that in some client classes the interface is used as parameter of a member function and that function is used to create instances of any classes which have the interface function implementations.

eg:

<?php

interface OutputInterface
{
    public function load();
}

class SerializedArrayOutput implements OutputInterface
{
    public function load()
    {
        return serialize($arrayOfData);
    }
}

class JsonStringOutput implements OutputInterface
{
    public function load()
    {
        return json_encode($arrayOfData);
    }
}

class ArrayOutput implements OutputInterface
{
    public function load()
    {
        return $arrayOfData;
    }
}


class SomeClient
{
    private $output;

    public function setOutput(OutputInterface $outputType)
    {
        $this->output = $outputType;
    }

    public function loadOutput()
    {
        return $this->output->load();
    }
}


$client = new SomeClient();

// Want an array?
$client->setOutput(new ArrayOutput());
$data = $client->loadOutput();

// Want some JSON?
$client->setOutput(new JsonStringOutput());
$data = $client->loadOutput();

4.Front Controller

The front controller pattern is where you have a single entrance point for your web application (e.g. index.php) that handles all of the requests. This code is responsible for loading all of the dependencies, processing the request and sending the response to the browser. The front controller pattern can be beneficial because it encourages modular code and gives you a central place to hook in code that should be run for every request (such as input sanitization).

 

5.Mode-View Controller (MVC)

The model-view-controller (MVC) pattern and its relatives HMVC and MVVM lets you break up code into logical objects that serve very specific purposes. Models serve as a data access layer where data is fetched and returned in formats usable throughout your application. Controllers handle the request, process the data returned from models and load views to send in the response. And views are display templates (markup, xml, etc) that are sent in the response to the web browser.