<?phpnamespace Illuminate\Container;use Illuminate\Contracts\Container\ContextualBindingBuilder as ContextualBindingBuilderContract;class ContextualBindingBuilder implements ContextualBindingBuilderContract{ /** * The underlying container instance. * * @var \Illuminate\Container\Container */ protected $container;// The underlying container instance /** * The concrete instance. * * @var string */ protected $concrete;// a instance about concrete /** * The abstract target. * * @var string */ protected $needs;// a target about the abstract /** * Create a new contextual binding builder. * * @param \Illuminate\Container\Container $container * @param string $concrete * @return void */ public function __construct(Container $container, $concrete) { $this->concrete = $concrete; $this->container = $container;// set the } /** * Define the abstract target that depends on the context. * * @param string $abstract * @return $this */ public function needs($abstract) { $this->needs = $abstract; return $this; }// function is needs /** * Define the implementation for the contextual binding. * * @param \Closure|string $implementation * @return void */ public function give($implementation) { $this->container->addContextualBinding($this->concrete, $this->needs, $implementation); }// Define the implementation for the contextual binding}