實(shí)現(xiàn)類(lèi)：

代碼如下:

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class Container
{
??? protected $setings = array();
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??? public function set($abstract, $concrete = null)
??? {
??????? if ($concrete === null) {
??????????? $concrete = $abstract;
??????? }
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??????? $this->setings[$abstract] = $concrete;
??? }
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??? public function get($abstract, $parameters = array())
??? {
??????? if (!isset($this->setings[$abstract])) {
??????????? return null;
??????? }
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??????? return $this->build($this->setings[$abstract], $parameters);
??? }
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??? public function build($concrete, $parameters)
??? {
??????? if ($concrete instanceof Closure) {
??????????? return $concrete($this, $parameters);
??????? }
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??????? $reflector = new ReflectionClass($concrete);
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??????? if (!$reflector->isInstantiable()) {
??????????? throw new Exception("Class {$concrete} is not instantiable");
??????? }
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??????? $constructor = $reflector->getConstructor();
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??????? if (is_null($constructor)) {
??????????? return $reflector->newInstance();
??????? }
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??????? $parameters = $constructor->getParameters();
??????? $dependencies = $this->getDependencies($parameters);
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??????? return $reflector->newInstanceArgs($dependencies);
??? }
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??? public function getDependencies($parameters)
??? {
??????? $dependencies = array();
??????? foreach ($parameters as $parameter) {
??????????? $dependency = $parameter->getClass();
??????????? if ($dependency === null) {
??????????????? if ($parameter->isDefaultValueAvailable()) {
??????????????????? $dependencies[] = $parameter->getDefaultValue();
??????????????? } else {
??????????????????? throw new Exception("Can not be resolve class dependency {$parameter->name}");
??????????????? }
??????????? } else {
??????????????? $dependencies[] = $this->get($dependency->name);
??????????? }
??????? }
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??????? return $dependencies;
??? }
}

實(shí)現(xiàn)實(shí)例：

代碼如下:

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require 'container.php';
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interface MyInterface{}
class Foo implements MyInterface{}
class Bar implements MyInterface{}
class Baz
{
??? public function __construct(MyInterface $foo)
??? {
??????? $this->foo = $foo;
??? }
}
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$container = new Container();
$container->set('Baz', 'Baz');
$container->set('MyInterface', 'Foo');
$baz = $container->get('Baz');
print_r($baz);
$container->set('MyInterface', 'Bar');
$baz = $container->get('Baz');
print_r($baz);