<?php
//容器类装实例或提供实例的回调函数
class Container {
protected $bindings = [];
//绑定接口和生成相应实例的回调函数
public function bind($abstract, $concrete=null, $shared=false) {
//如果提供的参数不是回调函数，则产生默认的回调函数
if(!$concrete instanceof Closure) {
$concrete = $this->getClosure($abstract, $concrete);
}
$this->bindings[$abstract] = compact('concrete', 'shared');
}
//默认生成实例的回调函数
protected function getClosure($abstract, $concrete) {
return function($c) use ($abstract, $concrete) {
$method = ($abstract == $concrete) ? 'build' : 'make';
return $c->$method($concrete);
};
}
public function make($abstract) {
$concrete = $this->getConcrete($abstract);
if($this->isBuildable($concrete, $abstract)) {
$object = $this->build($concrete);
} else {
$object = $this->make($concrete);
}
return $object;
}
protected function isBuildable($concrete, $abstract) {
return $concrete === $abstract || $concrete instanceof Closure;
}
//获取绑定的回调函数
protected function getConcrete($abstract) {
if(!isset($this->bindings[$abstract])) {
return $abstract;
}
return $this->bindings[$abstract]['concrete'];
}
//实例化对象
public function build($concrete) {
if($concrete instanceof Closure) {
return $concrete($this);
}
$reflector = new ReflectionClass($concrete);
if(!$reflector->isInstantiable()) {
echo $message = "Target [$concrete] is not instantiable";
}
$constructor = $reflector->getConstructor();
if(is_null($constructor)) {
return new $concrete;
}
$dependencies = $constructor->getParameters();
$instances = $this->getDependencies($dependencies);
return $reflector->newInstanceArgs($instances);
}
//解决通过反射机制实例化对象时的依赖
protected function getDependencies($parameters) {
$dependencies = [];
foreach($parameters as $parameter) {
$dependency = $parameter->getClass();
if(is_null($dependency)) {
$dependencies[] = NULL;
} else {
$dependencies[] = $this->resolveClass($parameter);
}
}
return (array)$dependencies;
}
protected function resolveClass(ReflectionParameter $parameter) {
return $this->make($parameter->getClass()->name);
}
}
class Traveller {
protected $trafficTool;
public function __construct(Visit $trafficTool) {
$this->trafficTool = $trafficTool;
}
public function visitTibet() {
$this->trafficTool->go();
}
}
interface Visit {
public function go();
}
class Train implements Visit {
public function go() {
echo "go to Tibet by train !!!";
}
}
$app = new Container();
$app->bind("Visit", "Train");
$app->bind("traveller", "Traveller");
$tra = $app->make("traveller");
$tra->visitTibet();
laravel框架中容器类简化代码-摘自某书的相关教程结束。
