特点
定义一系列算法封装起来, 让他们可以相互替代，策略模式提供了管理相关算法族的办法, 提供了可以体会继承关系的棒法, 避免使用多重条件转移语句
实现
<?php
abstract class Strategy
{
abstract function goSchool();
}
class Run extends Strategy
{
public function goSchool() {
echo "走路去学校";
}
}
class Subway extends Strategy
{
public function goSchool() {
echo "地铁去学校";
}
}
class Bike extends Strategy
{
public function goSchool() {
echo "公交去学校";
}
}
class GoSchoolContext
{
protected $_stratege;
public function __construct($stratege) {
$this->_stratege = $stratege;
}
public function goSchool()
{
$this->_stratege->goSchool();
}
}
$traget = new Run();
$obj = new GoSchoolContext($traget);
$obj->goSchool();
适配器模式
特点
需要的东西在面前，但却不能用，而短时间又无法改造它，于是就想办法适配
实现
// 适配器
interface Charget
{
public function putCharget();
}
class China implements Charget
{
private $v = 220;
public function putCharget()
{
return $this->v;
}
}
class Adper extends China
{
public function putCharget() {
return parent::putCharget() / 2 + 10;
}
}
class Phone
{
public function charge(Charget $charge)
{
if ($charge->putCharget() != "120") {
echo "不能充电";
} else {
echo "能充电";
}
}
}
$china = new China();
$adper = new Adper();
$phone = new Phone();
$phone->charge($adper);
观察者模式
特点
当一个对象状态发生变化时, 依赖他的对象全部收到通知, 并主动更新。观察者模式实现了低耦合, 非侵入式的通知与更新机制。
实现
<?php
// 主题接口
interface Subject
{
public function register(Observer $observer);
}
// 观察者接口
interface Observer
{
public function watch();
}
// 主题
class WatchAction implements Subject
{
public $_observers = [];
public function register(\Observer $observer) {
$this->_observers[] = $observer;
}
public function notify()
{
foreach($this->_observers as $object) {
$object->watch();
}
}
}
// 观察者
class Cat1 implements Observer{
public function watch(){
echo "Cat1 watches TV<hr/>";
}
}
class Dog1 implements Observer{
public function watch(){
echo "Dog1 watches TV<hr/>";
}
}
class People implements Observer{
public function watch(){
echo "People watches TV<hr/>";
}
}
$action = new WatchAction();
$action->register(new Cat1());
$action->register(new People());
$action->register(new Dog1());
$action->notify();
总结
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