学习php设计模式 php实现享元模式(flyweight)

<?php
/**
 * 抽象享元角色
 */
abstract class Flyweight {
 
 /**
  * 示意性方法
  * @param string $state 外部状态
  */
 abstract public function operation($state);
}
 
/**
 * 具体享元角色
 */
class ConcreteFlyweight extends Flyweight {
 
 private $_intrinsicState = null;
 
 /**
  * 构造方法
  * @param string $state 内部状态
  */
 public function __construct($state) {
  $this->_intrinsicState = $state;
 }
 
 public function operation($state) {
  echo 'ConcreteFlyweight operation, Intrinsic State = ' . $this->_intrinsicState
  . ' Extrinsic State = ' . $state . '<br />';
 }
 
}
 
/**
 * 不共享的具体享元，客户端直接调用
 */
class UnsharedConcreteFlyweight extends Flyweight {
 
 private $_intrinsicState = null;
 
 /**
  * 构造方法
  * @param string $state 内部状态
  */
 public function __construct($state) {
  $this->_intrinsicState = $state;
 }
 
 public function operation($state) {
  echo 'UnsharedConcreteFlyweight operation, Intrinsic State = ' . $this->_intrinsicState
  . ' Extrinsic State = ' . $state . '<br />';
 }
 
}
 
/**
 * 享元工厂角色
 */
class FlyweightFactory {
 
 private $_flyweights;
 
 public function __construct() {
  $this->_flyweights = array();
 }
 
 public function getFlyweigth($state) {
  if (isset($this->_flyweights[$state])) {
   return $this->_flyweights[$state];
  } else {
   return $this->_flyweights[$state] = new ConcreteFlyweight($state);
  }
 }
 
}
 
/**
 * 客户端
 */
class Client {
 
 /**
  * Main program.
  */
 public static function main() {
  $flyweightFactory = new FlyweightFactory();
  $flyweight = $flyweightFactory->getFlyweigth('state A');
  $flyweight->operation('other state A');
 
  $flyweight = $flyweightFactory->getFlyweigth('state B');
  $flyweight->operation('other state B');
 
  /* 不共享的对象，单独调用 */
  $uflyweight = new UnsharedConcreteFlyweight('state A');
  $uflyweight->operation('other state A');
 }
 
}
 
Client::main();
?>

<?php
/**
 * 抽象享元角色
 */
abstract class Flyweight {
 
 /**
  * 示意性方法
  * @param string $state 外部状态
  */
 abstract public function operation($state);
}
 
/**
 * 具体享元角色
 */
class ConcreteFlyweight extends Flyweight {
 
 private $_intrinsicState = null;
 
 /**
  * 构造方法
  * @param string $state 内部状态
  */
 public function __construct($state) {
  $this->_intrinsicState = $state;
 }
 
 public function operation($state) {
  echo 'ConcreteFlyweight operation, Intrinsic State = ' . $this->_intrinsicState
  . ' Extrinsic State = ' . $state . '<br />';
 }
 
}
 
/**
 * 不共享的具体享元，客户端直接调用
 */
class UnsharedConcreteFlyweight extends Flyweight {
 
 private $_flyweights;
 
 /**
  * 构造方法
  * @param string $state 内部状态
  */
 public function __construct() {
  $this->_flyweights = array();
 }
 
 public function operation($state) {
  foreach ($this->_flyweights as $flyweight) {
   $flyweight->operation($state);
  }
 }
 
 public function add($state, Flyweight $flyweight) {
  $this->_flyweights[$state] = $flyweight;
 }
 
}
 
/**
 * 享元工厂角色
 */
class FlyweightFactory {
 
 private $_flyweights;
 
 public function __construct() {
  $this->_flyweights = array();
 }
 
 public function getFlyweigth($state) {
  if (is_array($state)) { // 复合模式
   $uFlyweight = new UnsharedConcreteFlyweight();
 
   foreach ($state as $row) {
    $uFlyweight->add($row, $this->getFlyweigth($row));
   }
   return $uFlyweight;
  } else if (is_string($state)) {
   if (isset($this->_flyweights[$state])) {
    return $this->_flyweights[$state];
   } else {
    return $this->_flyweights[$state] = new ConcreteFlyweight($state);
   }
  } else {
   return null;
  }
 }
 
}
 
/**
 * 客户端
 */
class Client {
 
 /**
  * Main program.
  */
 public static function main() {
  $flyweightFactory = new FlyweightFactory();
  $flyweight = $flyweightFactory->getFlyweigth('state A');
  $flyweight->operation('other state A');
 
  $flyweight = $flyweightFactory->getFlyweigth('state B');
  $flyweight->operation('other state B');
 
  /* 复合对象*/
  $uflyweight = $flyweightFactory->getFlyweigth(array('state A', 'state B'));
  $uflyweight->operation('other state A');
 }
 
}
 
Client::main();
?>