public function __construct() {
$this->_observers = array();
}
public function add_observer($obs) {
$this->_observers[] = $obs;
}
public funtion delete_observer($bos) {
$index = array_search($bos, $this->_observers);
unset($this->_observers[$index]);
}
public function notify_observers() {
foreach($this->_observers as $v) {
$v->update();
}
}
}
//观察者
class Observer
{
public function __construct() {
do sth;
}
public function update() {
do sth;
}
}
//实例
$sub = new Subject();
$obs = new Observer();
$sub->add_observer($obs);
$sub->notify_observers();
js实现
js实现起来也不麻烦，就是得写些工具函数方便用，比如删除数组指定的元素。下面只用最简单的实现方法。
//被观察者
function Subject() {
var _this = this;
this.observers = [];
this.addObserver = function(obj) {
_this.observers.push(obj);
}
this.deleteObserver = function(obj) {
var length = _this.observers.length;
for(var i = 0; i < length; i++) {
if(_this.observers[i] === obj) {
_this.observers.splice(i, 1);
}
}
}
this.notifyObservers = function() {
var length = _this.observers.length;
console.log(length)
for(var i = 0; i < length; i++) {
_this.observers[i].update();
}
}
}
//观察者
function Observer() {
this.update = function() {
