问题二,这个其实也不算问题,就是写法上的优化,我们是不是每次都要传递第二个参数并且每次都要写一个闭包进去?
# class Container# 复制上面的代码
class Person{
public $name;
}
$container = new Container();
$container->bind('person' , function(){
return new Person();
},true);
我们来分析一下,实际上我已经知道了Person类,那么我们能不能想下面代码中的这么实现呢
...
$container = new Container();
$container->bind('Person' , 'Person' , true);
$container->bind('Person');
...
接下来继续改进
class Container {
private $bindings = [];
private $instances = [];
#这里是生成闭包的地方
public function getClosure($concrete) {
return function() use($concrete) {
return new $concrete;
};
}
public function bind($abstract , $concrete=null, $shared = false)
{
if (is_null($concrete)) {
$concrete = $abstract;
}
# 如果$concrete 不是一个闭包生成一个闭包
if (!$concrete instanceof Closure) {
$concrete = $this->getClosure($concrete);
}
$this->bindings[$abstract] = [
'concrete' => $concrete,
'shared' => $shared
];
}
public function make($abstract) {
if (!isset($this->bindings[$abstract])) {
return false;
}
if (isset($this->instances[$abstract])) {
return $this->instances[$abstract];
}
$object = $this->bindings[$abstract]['concrete']();
if($this->bindings[$abstract]['shared']) {
$this->instances[$abstract] = $object;
}
return $object;
}
}
class Person{
public $name;
}
# testing
$container = new Container();
$container->bind('Person' , 'Person' , false);
$p1 = $container->make('Person');
$p2 = $container->make('Person');
var_dump($p1 , $p2 , $p1 === $p2);
$c1 = new Container();
$c1->bind('Person');
$p3 = $c1->make('Person');
$p4 = $c1->make('Person');
var_dump($p3 , $p4 , $p3 === $p4);
$c2 = new Container();
$c2->bind('Person','Person', true);
$p5 = $c2->make('Person');
$p6 = $c2->make('Person');
var_dump($p5 , $p6 , $p5 === $p6);
入门我们自己写这个container大部门人会在make里去判断是否是一个闭包,写完就不再优化了...