class MyClass { private $logger; public function attachLogger(Logger $logger) { $this->logger = $logger; } public function doSomething() { // Do something... $this->logger->log('Something was done...'); } } $myObj = new MyClass(); $loggerObj = new Logger(); $myObj->attachLogger($loggerObj); $myObj->doSomething();
class Database { private $cache; public function attachCache(Cache $cache) { $this->cache = $cache; } public function getData($key) { if ($this->cache->has($key)) { return $this->cache->get($key); } // Fetch data from database... $data = fetchDataFromDatabase(); // Cache the data and return it... $this->cache->set($key, $data); return $data; } } $dbObj = new Database(); $cacheObj = new Cache(); $dbObj->attachCache($cacheObj); $data = $dbObj->getData('my_key');In this example, a caching object is attached to the Database object using the `attachCache()` method. When the `getData()` method is called, it first checks if the data is already cached. If so, it returns the cached data, otherwise it fetches the data from the database, caches it, and returns it. The package library for the PHP Object Attachment pattern could be any library that provides object-oriented programming functionality in PHP, such as Symfony, Laravel, or Zend.