PHP Design Patterns: Factory Pattern

php_design_patterns_factory_pattern.php

<?php

interface Dog
{
  public function speak ();
}

class Poodle implements Dog
{
  public function speak()
  {
    echo "The poodle says \"arf\"\n";
  }
}
 
class Rottweiler implements Dog
{
  public function speak()
  {
    echo "The Rottweiler says (in a very deep voice) \"WOOF!\"\n";
  }
}
 
class SiberianHusky implements Dog
{
  public function speak()
  {
    echo "The husky says \"Dude, what's up?\"\n";
  }
}

class DogFactory
{
  public function getDog($criteria)
  {
    if ( $criteria == "small" )
      return new Poodle();
    else if ( $criteria == "big" )
      return new Rottweiler();
    else if ( $criteria == "working" )
      return new SiberianHusky();
 
    return null;
  }
}

$dogFactory = new DogFactory();

$dog = $dogFactory->getDog("small");
$dog->speak();


$dog = $dogFactory->getDog("big");
$dog->speak();

$dog = $dogFactory->getDog("working");
$dog->speak();