《HeadFirst设计模式》代码之PHP版(面向对象学习)_php技巧

书中的例子都比较浅显易懂，不过由于是外国佬写的，所以例子的习惯不是很附合中国特色，可能偶尔看起来有些别扭，还有语言习惯也不是中国风。当然��看过这本书之后，你才能深刻理解设计模式到底能为你解决哪些问题，不能为你解决哪些问题（比如不能代替你的编码）。
　　我将书中部分代码改成PHP，看下代码再配合概念应该是比较容易理解了。

策略模式

代码如下:

<?php 
/** 
* 策略模式 
* 定义了算法族，分别封装起来，让它们之间可以互相替换， 
* 此模式让算法的变化独立于使用算法的客户。 
*/ 
//飞行行为接口 
interface FlyBehavior { 
public function fly(); 
} 
//呱呱叫行为接口 
interface QuackBehavior { 
public function quack(); 
} 
//翅膀飞行 
class FlyWithWings implements FlyBehavior { 
public function fly() { 
echo "I'm flying!!\n"; 
} 
} 
//不会飞 
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(); 
?>

单件模式

代码如下:

<?php 
/** 
* 单件模式 
* 确保一个类只有一个实例，并提供一个全局访问点。 
*/ 
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); 
?>

工厂方法模式

代码如下:

<?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"; 
?>

工厂模式

代码如下:

<?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'); 
?>

观察者模式

代码如下:

<?php 
/** 
* 观察者模式 
* 定义了对象之间的一对多依赖，当一个对象改变状态时， 
* 它的所有依赖者都会收到通知并自动更新。 
*/ 
interface Subject { 
public function registerObserver(Observer $o); 
public function removeObserver(Observer $o); 
public function notifyObservers(); 
} 
interface Observer { 
public function update($temperature, $humidity, $pressure); 
} 
interface DisplayElement { 
public function display(); 
} 
class WeatherData implements Subject { 
private $observers = array(); 
private $temperature; 
private $humidity; 
private $pressure; 
public function __construct() { 
$this->observers = array(); 
} 
public function registerObserver(Observer $o) { 
$this->observers[] = $o; 
} 
public function removeObserver(Observer $o) { 
if (($key = array_search($o, $this->observers)) !== false) { 
unset($this->observers[$key]); 
} 
} 
public function notifyObservers() { 
foreach ($this->observers as $observer) { 
$observer->update($this->temperature, $this->humidity, $this->pressure); 
} 
} 
public function measurementsChanged() { 
$this->notifyObservers(); 
} 
public function setMeasurements($temperature, $humidity, $pressure) { 
$this->temperature = $temperature; 
$this->humidity = $humidity; 
$this->pressure = $pressure; 
$this->measurementsChanged(); 
} 
} 
class CurrentConditionsDisplay implements Observer, DisplayElement { 
private $temperature; 
private $humidity; 
private $weatherData; 
public function __construct(Subject $weatherData) { 
$this->weatherData = $weatherData; 
$weatherData->registerObserver($this); 
} 
public function update($temperature, $humidity, $pressure) { 
$this->temperature = $temperature; 
$this->humidity = $humidity; 
$this->display(); 
} 
public function display() { 
echo "温度：" . $this->temperature . "; 湿度：" . $this->humidity . "%\n"; 
} 
} 
class StatistionsDisplay implements Observer, DisplayElement { 
private $temperature; 
private $humidity; 
private $pressure; 
private $weatherData; 
public function __construct(Subject $weatherData) { 
$this->weatherData = $weatherData; 
$weatherData->registerObserver($this); 
} 
public function update($temperature, $humidity, $pressure) { 
$this->temperature = $temperature; 
$this->humidity = $humidity; 
$this->pressure = $pressure; 
$this->display(); 
} 
public function display() { 
echo "温度：" . $this->temperature . "; 湿度：" . $this->humidity . "%; 气压：" . $this->pressure . "\n"; 
} 
} 
$weatherData = new WeatherData(); 
$currentDisplay = new CurrentConditionsDisplay($weatherData); 
$statistionDisplay = new StatistionsDisplay($weatherData); 
$weatherData->setMeasurements(10, 20, 30); 
$weatherData->removeObserver($currentDisplay); 
$weatherData->setMeasurements(30, 40, 50); 
?>

命令模式

代码如下:

<?php 
class Light { 
public function __construct() { 
} 
public function on() { 
echo "Light On\n"; 
} 
public function off() { 
echo "Light Off\n"; 
} 
} 
interface Command { 
public function execute(); 
} 
class LightOnCommand implements Command { 
public $light; 
public function __construct(Light $light) { 
$this->light = $light; 
} 
public function execute() { 
$this->light->on(); 
} 
} 
class SimpleRemoteControl { 
public $slot; 
public function __construct() { 
} 
public function setCommand(Command $command) { 
$this->slot = $command; 
} 
public function buttonWasPressed() { 
$this->slot->execute(); 
} 
} 
class RemoteControlTest { 
public static function main() { 
$remote = new SimpleRemoteControl(); 
$light = new Light(); 
$lightOn = new LightOnCommand($light); 
$remote->setCommand($lightOn); 
$remote->buttonWasPressed(); 
} 
} 
RemoteControlTest::main(); 
?>

装饰者模式

代码如下:

<?php 
/** 
* 装饰着模式 
* 动态地将责任附加到对象上，若要扩展功能，装饰者提供了比继承更有弹性的替代方案。 
*/ 
abstract class Beverage { 
public $description = "Unknown Beverage"; 
public function getDescription() { 
return $this->description; 
} 
public abstract function cost(); 
} 
abstract class CondimentDecorator extends Beverage { 
//JAVA代码里这里是个抽象类，PHP不允许这么做 
public function getDescription() { 
return $this->description; 
} 
} 
class Espresso extends Beverage { 
public function __construct() { 
$this->description = "Espresso"; 
} 
public function cost() { 
return 1.99; 
} 
} 
class HouseBlend extends Beverage { 
public function __construct() { 
$this->description = "HouseBlend"; 
} 
public function cost() { 
return .89; 
} 
} 
class DarkRoast extends Beverage { 
public function __construct() { 
$this->description = "DarkRoast"; 
} 
public function cost() { 
return .99; 
} 
} 
class Mocha extends CondimentDecorator { 
public $beverage; 
public function __construct(Beverage $beverage) { 
$this->beverage = $beverage; 
} 
public function getDescription() { 
return $this->beverage->getDescription() . ", Mocha"; 
} 
public function cost() { 
return .20 + $this->beverage->cost(); 
} 
} 
class Whip extends CondimentDecorator { 
public $beverage; 
public function __construct(Beverage $beverage) { 
$this->beverage = $beverage; 
} 
public function getDescription() { 
return $this->beverage->getDescription() . ", Whip"; 
} 
public function cost() { 
return .10 + $this->beverage->cost(); 
} 
} 
class Soy extends CondimentDecorator { 
public $beverage; 
public function __construct(Beverage $beverage) { 
$this->beverage = $beverage; 
} 
public function getDescription() { 
return $this->beverage->getDescription() . ", Soy"; 
} 
public function cost() { 
return .15 + $this->beverage->cost(); 
} 
} 
$beverage = new Espresso(); 
echo $beverage->getDescription() . "\n"; 
$beverage2 = new DarkRoast(); 
$beverage2 = new Mocha($beverage2); 
$beverage2 = new Mocha($beverage2); 
$beverage2 = new Whip($beverage2); 
echo $beverage2->getDescription() . " $" . $beverage2->cost() . "\n"; 
$beverage3 = new HouseBlend(); 
$beverage3 = new Soy($beverage3); 
$beverage3 = new Mocha($beverage3); 
$beverage3 = new Whip($beverage3); 
echo $beverage3->getDescription() . " $" . $beverage3->cost() . "\n"; 
?>

状态模式

代码如下:

<?php 
class GumballMachine { 
const SOLD_OUT = 0; 
const NO_QUARTER = 1; 
const HAS_QUARTER = 2; 
const SOLD = 3; 
public $state = self::SOLD_OUT; 
public $count = 0; 
public function __construct($count) { 
$this->count = $count; 
if ($count > 0) { 
$this->state = self::NO_QUARTER; 
} 
} 
public function insertQuarter() { 
if ($this->state == self::HAS_QUARTER) { 
echo "You can't insert another quarter!\n"; 
} else if ($this->state == self::NO_QUARTER) { 
$this->state = self::HAS_QUARTER; 
echo "You inserted a quarter!\n"; 
} else if ($this->state == self::SOLD_OUT) { 
echo "You can't insert a quarter, the machine is sold out!\n"; 
} else if ($this->state == self::SOLD) { 
echo "Please wait, we're already giving you a gumball!\n"; 
} 
} 
} 
$obj = new GumballMachine(0); 
print_r($obj) 
?>

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