Shikiryu_Backup/app/code/backup/Folder.php

<?php

namespace Shikiryu\Backup\Backup;

class Folder extends BackupAbstract
{
    public function __construct(array $config = array())
    {
        parent::__construct($config);
    }

    /**
    * @return bool
    */
    public function isValid()
    {
        // TODO: Implement isValid() method.
    }

    /**
    * Function that can be used to initialize the backup
    */
    protected function preBuild()
    {
        // TODO: Implement preBuild() method.
    }

    /**
    * Function that can be used after the backup
    */
    protected function postBuild()
    {
        // TODO: Implement postBuild() method.
    }

    /**
    * Mandatory function doing the backup
    */
    protected function build()
    {
        // TODO: Implement build() method.
    }
}