Decorator パターン | デザインパターン
2022年9年23日
デザインパターン
Decorator
PHP
オライリージャパンによる Head First シリーズ デザインパターン（第2版）第3章 Observer パターンを、PHPで書き直してみようという試みです。
Beverage.php
namespace Decorator;
abstract class Beverage {
public string $description = '不明な飲み物';
public function getDescription() : string {
return $this->description;
}
public abstract function cost() : float;
}
Espresso.php
namespace Decorator;
class Espresso extends Beverage {
public function __construct() {
$this->description = 'エスプレッソ';
}
public function cost() : float {
return 1.99;
}
}
DarkRoast.php
namespace Decorator;
class DarkRoast extends Beverage {
public function __construct() {
$this->description = 'ダークローストコーヒー';
}
public function cost() : float {
return 0.99;
}
}
HouseCoffee.php
namespace Decorator;
class HouseCoffee extends Beverage {
public function __construct(){
$this->description = 'ハウスブレンドコーヒー';
}
public function cost() : float {
return 0.89;
}
}
CondimentDecorator.php
namespace Decorator;
abstract class CondimentDecorator extends Beverage {
public Beverage $beverage;
}
Soy.php
namespace Decorator;
class Soy extends CondimentDecorator {
public function __construct(Beverage $beverage){
$this->beverage = $beverage;
}
public function getDescription() : string {
return $this->beverage->getDescription() . '、豆乳';
}
public function cost() : float {
return $this->beverage->cost() + 0.15;
}
}
Mocha.php
namespace Decorator;
class Mocha extends CondimentDecorator {
public function __construct(Beverage $beverage){
$this->beverage = $beverage;
}
public function getDescription() : string {
return $this->beverage->getDescription() . '、モカ';
}
public function cost() : float {
return $this->beverage->cost() + 0.20;
}
}
Whip.php
namespace Decorator;
class Whip extends CondimentDecorator {
public function __construct(Beverage $beverage){
$this->beverage = $beverage;
}
public function getDescription() : string {
return $this->beverage->getDescription() . '、ホイップ';
}
public function cost() : float {
return $this->beverage->cost() + 0.10;
}
}
index.php
use Decorator\Espresso;
use Decorator\DarkRoast;
use Decorator\HouseCoffee;
use Decorator\Soy;
use Decorator\Mocha;
use Decorator\Whip;
$beverage = new Espresso();
echo $beverage->getDescription() . ' $' . $beverage->cost();
echo "\n";
$beverage2 = new DarkRoast();
$beverage2 = new Mocha($beverage2);
$beverage2 = new Mocha($beverage2);
$beverage2 = new Whip($beverage2);
echo $beverage2->getDescription() . ' $' . $beverage2->cost();
echo "\n";
$beverage3 = new HouseCoffee();
$beverage3 = new Soy($beverage3);
$beverage3 = new Mocha($beverage3);
$beverage3 = new Whip($beverage3);
echo $beverage3->getDescription() . ' $' . $beverage3->cost();
echo "\n";
出力結果
エスプレッソ $1.99
ダークローストコーヒー、モカ、モカ、ホイップ $1.49
ハウスブレンドコーヒー、豆乳、モカ、ホイップ $1.34
