function clear($key_token = null)
{
foreach ($this->_index as $authorized_key => $time_stored) {
if (isset($key_token) && strpos($authorized_key, $key_token) === FALSE) {
continue;
}
$this->delete($authorized_key);
}
$file_set = AMPfile_list($this->_path_cache);
$this->_load_file();
foreach ($file_set as $file_name => $file_display) {
if (!$file_name) {
continue;
}
if (isset($key_token) && strpos($file_name, $key_token) === FALSE) {
continue;
}
$entry_ref = new AMP_System_File($this->_path($file_name));
if ($entry_ref->getTime() + AMP_SYSTEM_CACHE_TIMEOUT < time()) {
$entry_ref->delete();
}
}
}
