/**
- 方法示例
*/
public function handle(Context $context);
}
/**
- 具体状态角色A
- 单例类
/
class ConcreteStateA implements State {
/ 唯一的实例 */
private static $_instance = null;
private function __construct() {
}
/**
- 静态工厂方法，返还此类的唯一实例
*/
public static function getInstance() {
if (is_null(self::$_instance)) {
self::$_instance = new ConcreteStateA();
}
return self::$_instance;
}
public function handle(Context $context) {
echo 'Concrete Sate A handle method
';
$context->setState(ConcreteStateB::getInstance());
}
}
/**
- 具体状态角色B
- 单例类
/
class ConcreteStateB implements State {
/ 唯一的实例 */
private static $_instance = null;
private function __construct() {
}
/**
- 静态工厂方法，返还此类的唯一实例
*/
public static function getInstance() {
if (is_null(self::$_instance)) {
self::$_instance = new ConcreteStateB();
}
return self::$_instance;
}
public function handle(Context $context) {
echo 'Concrete Sate B handle method
';
$context->setState(ConcreteStateA::getInstance());
}
}
/**
private $_state;
/**
- 默认为StateA
*/
public function __construct() {
$this->_state = ConcreteStateA::getInstance();
}
public function setState(State $state) {
$this->_state = $state;
}
public function request() {
$this->_state->handle($this);
}
}
/**
/**
- Main program.
*/
public static function main() {
$context = new Context();
$context->request();
$context->request();
$context->request();
$context->request();
}
}
Client::main();
?>
