php设计模式之备忘录模式

<?php
/**
* 备忘录模式
*
* 在不破坏封装性的前提下,捕获一个对象的内部状态,并在该对象之外保存这个状态,这样以后就可以将该对象恢复到保存的状态
*/
class Memento {
private $_state = null;
public function __construct($state) {
$this->_state = $state;
}
public function getState() {
return $this->_state;
}
}
class Caretaker {
private $_memento = null;
public function getMemento() {
return$ this->
_memento;
}
public function setMemento($memento) {
$this->_memento = $memento;
}
}
class Originator {
private $_state = null;
public function getState() {
return $this->_state;
}
public function setState($state) {
$this->_state = $state;
}
public function createMemento() {
return new Memento ( $this->_state );
}
public function setMemento($memento) {
$this->_state = $memento->getState ();
}
public function display() {
echo "state = " . $this->_state . "<br/>";
}
}

$objOriginator = new Originator ();
$objOriginator->setState ( 0 );
$objOriginator->display ();

$objCareTaker = new CareTaker ();
$objCareTaker->setMemento ( $objOriginator->createMemento () );

$objOriginator->setState ( 1 );
$objOriginator->display ();

$objOriginator->setMemento ( $objCareTaker->getMemento () );
$objOriginator->display ();