PHP设计模式-11. 备忘录模式 (Memento)

概念: 在不违反封装性的前提下，捕获一个对象的内部状态，并在需要时恢复对象的状态

class Memento {
    private $state;

    public function __construct($state) {
        $this->state = $state;
    }

    public function getState() {
        return $this->state;
    }
}

class Originator {
    private $state;

    public function setState($state) {
        $this->state = $state;
    }

    public function save() {
        return new Memento($this->state);
    }

    public function restore(Memento $memento) {
        $this->state = $memento->getState();
    }
}

// 使用
$originator = new Originator();
$originator->setState("State1");
$memento = $originator->save();

$originator->setState("State2");
$originator->restore($memento); // 恢复为 State1