書中的例子都比較淺顯易懂，不過由於是外國佬寫的，所以例子的習慣不是很附合中國特色，可能偶爾看起來有些別扭，還有語言習慣也不是中國風。當然��看過這本書之後，你才能深刻理解設計模式到底能為你解決哪些問題，不能為你解決哪些問題（比如不能代替你的編碼）。
我將書中部分代碼改成PHP，看下代碼再配合概念應該是比較容易理解了。
策略模式
復制代碼 代碼如下:
<?php
/**
* 策略模式
* 定義了算法族，分別封裝起來，讓它們之間可以互相替換，
* 此模式讓算法的變化獨立於使用算法的客戶。
*/
//飛行行為接口
interface FlyBehavior {
public function fly();
}
//呱呱叫行為接口
interface QuackBehavior {
public function quack();
}
//翅膀飛行
class FlyWithWings implements FlyBehavior {
public function fly() {
echo "I'm flying!!\n";
}
}
//不會飛
class FlyNoWay implements FlyBehavior {
public function fly() {
echo "I can't fly!\n";
}
}
class FlyRocketPowered implements FlyBehavior {
public function fly() {
echo "I'm flying with a rocket!\n";
}
}
class Qquack implements QuackBehavior {
public function quack() {
echo "Quack\n";
}
}
class Squeak implements QuackBehavior {
public function quack() {
echo "Squeak\n";
}
}
class MuteQuack implements QuackBehavior {
public function quack() {
echo "<< Silence >>\n";
}
}
abstract class Duck {
protected $quack_obj;
protected $fly_obj;
public abstract function display();
public function performQuack() {
$this->quack_obj->quack();
}
public function performFly() {
$this->fly_obj->fly();
}
public function swim() {
echo "All ducks float, even decoys!\n";
}
public function setFlyBehavior(FlyBehavior $fb) {
$this->fly_obj = $fb;
}
public function setQuackBehavior(QuackBehavior $qb) {
$this->quack_obj = $qb;
}
}
class ModelDuck extends Duck {
public function __construct() {
$this->fly_obj = new FlyNoWay();
$this->quack_obj = new MuteQuack();
}
public function display() {
echo "I'm a model duck!\n";
}
}
$model = new ModelDuck();
$model->performFly();
$model->performQuack();
//提供新的能力
$model->setFlyBehavior(new FlyRocketPowered());
$model->setQuackBehavior(new Squeak());
$model->performFly();
$model->performQuack();
?>
單件模式
復制代碼 代碼如下:
<?php
/**
* 單件模式
* 確保一個類只有一個實例，並提供一個全局訪問點。
*/
class MyClass {
private static $uniqueInstance;
private function __construct() {
}
public static function getInstance() {
if (self::$uniqueInstance == null) {
self::$uniqueInstance = new MyClass();
}
return self::$uniqueInstance;
}
}
$myClass = MyClass::getInstance();
var_dump($myClass);
$myClass = MyClass::getInstance();
var_dump($myClass);
?>
工廠方法模式
復制代碼 代碼如下:
<?php
abstract class PizzaStore {
public function orderPizza($type) {
$pizza = $this->createPizza($type);
$pizza->prepare();
$pizza->bake();
$pizza->cut();
$pizza->box();
return $pizza;
}
public abstract function createPizza($type);
}
class NYPizzaStore extends PizzaStore {
public function createPizza($type) {
if ($type == "cheese") {
return new NYStyleCheesePizza();
} elseif ($type == "veggie") {
return new NYStyleVeggiePizza();
} elseif ($type == "clam") {
return new NYStyleClamPizza();
} elseif ($type == "papperoni") {
return new NYStylePapperoniPizza();
} else {
return null;
}
}
}
class ChicagoPizzaStore extends PizzaStore {
public function createPizza($type) {
if ($type == "cheese") {
return new ChicagoStyleCheesePizza();
} elseif ($type == "veggie") {
return new ChicagoStyleVeggiePizza();
} elseif ($type == "clam") {
return new ChicagoStyleClamPizza();
} elseif ($type == "papperoni") {
return new ChicagoStylePapperoniPizza();
} else {
return null;
}
}
}
abstract class Pizza {
public $name;
public $dough;
public $sauce;
public $toppings = array();
public function prepare() {
echo "Preparing " . $this->name . "\n";
echo "Yossing dough...\n";
echo "Adding sauce...\n";
echo "Adding toppings: \n";
for ($i = 0; $i < count($this->toppings); $i++) {
echo " " . $this->toppings[$i] . "\n";
}
}
public function bake() {
echo "Bake for 25 minutes at 350\n";
}
public function cut() {
echo "Cutting the pizza into diagonal slices\n";
}
public function box() {
echo "Place pizza in official PizzaStore box\n";
}
public function getName() {
return $this->name;
}
}
class NYStyleCheesePizza extends Pizza {
public function __construct() {
$this->name = "NY Style Sauce and cheese Pizza";
$this->dough = "Thin Crust Dough";
$this->sauce = "Marinara Sauce";
$this->toppings[] = "Grated Reggiano Cheese";
}
}
class NYStyleVeggiePizza extends Pizza {
public function __construct() {
$this->name = "NY Style Sauce and veggie Pizza";
$this->dough = "Thin Crust Dough";
$this->sauce = "Marinara Sauce";
$this->toppings[] = "Grated Reggiano veggie";
}
}
class NYStyleClamPizza extends Pizza {
public function __construct() {
$this->name = "NY Style Sauce and clam Pizza";
$this->dough = "Thin Crust Dough";
$this->sauce = "Marinara Sauce";
$this->toppings[] = "Grated Reggiano clam";
}
}
class NYStylePapperoniPizza extends Pizza {
public function __construct() {
$this->name = "NY Style Sauce and papperoni Pizza";
$this->dough = "Thin Crust Dough";
$this->sauce = "Marinara Sauce";
$this->toppings[] = "Grated Reggiano papperoni";
}
}
class ChicagoStyleCheesePizza extends Pizza {
public function __construct() {
$this->name = "Chicago Style Deep Dish Cheese Pizza";
$this->dough = "Extra Thick Crust Dough";
$this->sauce = "Plum Tomato Sauce";
$this->toppings[] = "Shredded Mozzarella Cheese";
}
public function cut() {
echo "Cutting the pizza into square slices\n";
}
}
$myStore = new NYPizzaStore();
$chicagoStore = new ChicagoPizzaStore();
$pizza = $myStore->orderPizza("cheese");
echo "Ethan ordered a " . $pizza->getName() . "\n";
$pizza = $chicagoStore->orderPizza("cheese");
echo "Ethan ordered a " . $pizza->getName() . "\n";
?>
工廠模式
復制代碼 代碼如下:
<?php
abstract class PizzaStore {
public function orderPizza($type) {
$pizza = $this->createPizza($type);
$pizza->prepare();
$pizza->bake();
$pizza->cut();
$pizza->box();
return $pizza;
}
public abstract function createPizza($type);
}
class NYPizzaStore extends PizzaStore {
public function createPizza($type) {
$pizza = null;
$ingredientFactory = new NYPizzaIngredientFactory();
if ($type == "cheese") {
$pizza = new CheesePizza($ingredientFactory);
$pizza->setName('New York Style Cheese Pizza');
} elseif ($type == "veggie") {
$pizza = new VeggiePizza($ingredientFactory);
$pizza->setName('New York Style Veggie Pizza');
} elseif ($type == "clam") {
$pizza = new ClamPizza($ingredientFactory);
$pizza->setName('New York Style Clam Pizza');
} elseif ($type == "papperoni") {
$pizza = new PapperoniPizza($ingredientFactory);
$pizza->setName('New York Style Papperoni Pizza');
}
return $pizza;
}
}
class ChicagoPizzaStore extends PizzaStore {
public function createPizza($type) {
if ($type == "cheese") {
return new ChicagoStyleCheesePizza();
} elseif ($type == "veggie") {
return new ChicagoStyleVeggiePizza();
} elseif ($type == "clam") {
return new ChicagoStyleClamPizza();
} elseif ($type == "papperoni") {
return new ChicagoStylePapperoniPizza();
} else {
return null;
}
}
}
interface PizzaIngredientFactory {
public function createDough();
public function createSauce();
public function createCheese();
public function createVeggies();
public function createPepperoni();
public function createClam();
}
class NYPizzaIngredientFactory implements PizzaIngredientFactory {
public function createDough() {
return new ThinCrustDough();
}
public function createSauce() {
return new MarinaraSauce();
}
public function createCheese() {
return new ReggianoCheese();
}
public function createVeggies() {
$veggies = array(
new Garlic(),
new Onion(),
new Mushroom(),
new RedPepper(),
);
return $veggies;
}
public function createPepperoni() {
return new SlicedPepperoni();
}
public function createClam() {
return new FreshClams();
}
}
class ChicagoPizzaIngredientFactory implements PizzaIngredientFactory {
public function createDough() {
return new ThickCrustDough();
}
public function createSauce() {
return new PlumTomatoSauce();
}
public function createCheese() {
return new Mozzarella();
}
public function createVeggies() {
$veggies = array(
new BlackOlives(),
new Spinach(),
new EggPlant(),
);
return $veggies;
}
public function createPepperoni() {
return new SlicedPepperoni();
}
public function createClam() {
return new FrozenClams();
}
}
abstract class Pizza {
public $name;
public $dough;
public $sauce;
public $veggies = array();
public $cheese;
public $pepperoni;
public $clam;
public abstract function prepare();
public function bake() {
echo "Bake for 25 minutes at 350\n";
}
public function cut() {
echo "Cutting the pizza into diagonal slices\n";
}
public function box() {
echo "Place pizza in official PizzaStore box\n";
}
public function getName() {
return $this->name;
}
public function setName($name) {
$this->name = $name;
}
public function __toString() {
}
}
class CheesePizza extends Pizza {
public $ingredientFactory;
public function __construct(PizzaIngredientFactory $ingredientFactory) {
$this->ingredientFactory = $ingredientFactory;
}
public function prepare() {
echo "Preparing " . $this->name . "\n";
$this->dough = $this->ingredientFactory->createDough();
$this->sauce = $this->ingredientFactory->createSauce();
$this->cheese = $this->ingredientFactory->createCheese();
}
}
class ClamPizza extends Pizza {
public $ingredientFactory;
public function __construct(PizzaIngredientFactory $ingredientFactory) {
$this->ingredientFactory = $ingredientFactory;
}
public function prepare() {
echo "Preparing " . $this->name . "\n";
$this->dough = $this->ingredientFactory->createDough();
$this->sauce = $this->ingredientFactory->createSauce();
$this->cheese = $this->ingredientFactory->createCheese();
$clam = $this->ingredientFactory->createClam();
}
}
$nyPizzaStore = new NYPizzaStore();
$nyPizzaStore->orderPizza('cheese');
?>
