Question

I am trying to build a simple abstract Cache class that can enforce methods in subclasses and I am trying to set up default settings for the subclasses to inherit. Here is my basic run down:

    define('APP_ROOT', getcwd());        
    abstract class BaseCache {

            protected $baseCacheDir = APP_ROOT . '/cache';

            abstract function exists($resource);
            abstract function store($resource);
            abstract function delete($resource);
            abstract function check($resource);
        }

    class TemplateCache extends BaseCache {

            protected $CacheDir = $this->baseCacheDir . '/tpl/';
            public function exists($resource) {}...
         }

class LinkCache extends BaseCache {

            protected $CacheDir = $this->baseCacheDir . '/link/';
        }

Is this the proper/best practices way to do this? Is this how you access properties in abstract classes while in a subclass? The $baseCacheDir property shouldn’t be changed and I want to hard-code it in as a default, then have subclasses build off of the base directory. (e.g ‘cache/link’, ‘cache/tpl’, ‘cache/apc’, ‘cache/memcache’)

Thanks.

Answer 1

abstract class BaseCache {

    private $baseCacheDir = APP_ROOT . '/cache';

    protected final  function getBaseCacheDir() 
    {
        return $this->baseCacheDir;
    }

    //And Anoter Thing
    protected final  function getBaseCacheDirConcat($tplDir)
    { 
        return $this->getBaseCacheDir().$tplDir
    } 

    abstract function exists($resource);
    abstract function store($resource);
    abstract function delete($resource);
    abstract function check($resource);
}

class LinkCache extends BaseCache {

    protected $CacheDir;

    public function __construct() 
    {
        $this->CacheDir = $this->getBaseCacheDirConcat('/link/');
    }

}