Laravel 源码 Collection（集合）请教

Collection.php

/** * @property-read HigherOrderCollectionProxy $average * @property-read HigherOrderCollectionProxy $avg * @property-read HigherOrderCollectionProxy $contains * @property-read HigherOrderCollectionProxy $each * @property-read HigherOrderCollectionProxy $every * @property-read HigherOrderCollectionProxy $filter * @property-read HigherOrderCollectionProxy $first * @property-read HigherOrderCollectionProxy $flatMap * @property-read HigherOrderCollectionProxy $groupBy * @property-read HigherOrderCollectionProxy $keyBy * @property-read HigherOrderCollectionProxy $map * @property-read HigherOrderCollectionProxy $max * @property-read HigherOrderCollectionProxy $min * @property-read HigherOrderCollectionProxy $partition * @property-read HigherOrderCollectionProxy $reject * @property-read HigherOrderCollectionProxy $sortBy * @property-read HigherOrderCollectionProxy $sortByDesc * @property-read HigherOrderCollectionProxy $sum * @property-read HigherOrderCollectionProxy $unique * * Class Collection */ /** * The methods that can be proxied. * * @var array */ protected static $proxies = [ 'average', 'avg', 'contains', 'each', 'every', 'filter', 'first', 'flatMap', 'groupBy', 'keyBy', 'map', 'max', 'min', 'partition', 'reject', 'sortBy', 'sortByDesc', 'sum', 'unique', ]; /** * Dynamically access collection proxies. * * @param string $key * @return mixed * * @throws \Exception */ public function __get($key) { if (! in_array($key, static::$proxies)) { throw new Exception("Property [{$key}] does not exist on this collection instance."); } return new HigherOrderCollectionProxy($this, $key); } 

HigherOrderCollectionProxy.php

 /** * Create a new proxy instance. * * @param \Illuminate\Support\Collection $collection * @param string $method * @return void */ public function __construct(Collection $collection, $method) { $this->method = $method; $this->collection = $collection; } /** * Proxy accessing an attribute onto the collection items. * * @param string $key * @return mixed */ public function __get($key) { return $this->collection->{$this->method}(function ($value) use ($key) { return is_array($value) ? $value[$key] : $value->{$key}; }); } /** * Proxy a method call onto the collection items. * * @param string $method * @param array $parameters * @return mixed */ public function __call($method, $parameters) { return $this->collection->{$this->method}(function ($value) use ($method, $parameters) { return $value->{$method}(...$parameters); }); } 

我的问题是这里为什么要用 HigherOrderCollectionProxy 来代理，有什么好处？这些方法都是 public 形式的，直接调用方法不好吗？