状态模式,属于行为型的设计模式。当一个对象的内在状态发生改变时,允许改变其行为,这个对象看起来像是改变了其类。
消除复杂的分支语句。
增加类的数量,增加复杂度。
abstract class State {
abstract function doSth(Order $order);
}
class ZeroStatus extends State {
public function doSth(Order $order) {
if($order->status == 0) {
echo "已下单\n";
} else {
$order->setObj(new OneStatus());
$order->doSth();
}
}
}
class OneStatus extends State {
public function doSth(Order $order) {
if($order->status == 1) {
echo "已支付\n";
} else {
$order->setObj(new TwoStatus());
$order->doSth();
}
}
}
class TwoStatus extends State {
public function doSth(Order $order) {
if($order->status == 2) {
echo "待收货\n";
} else {
echo "...";
}
}
}
class Order {
private $obj;
public $status;
public function __construct() {
$this->obj = new ZeroStatus();
}
public function setObj(State $state) {
$this->obj = new $state;
}
public function setStatus($status) {
$this->status = $status;
}
public function doSth() {
$this->obj->doSth($this);
}
}
$order = new Order();
$order->setStatus(0);
$order->doSth();
$order->setStatus(1);
$order->doSth();
$order->setStatus(2);
$order->doSth();
$order->setStatus(3);
$order->doSth();
转载自: https://www.cnblogs.com/phpphp/p/17033753.html